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.ds vE rev 2.02, December 13, 2011
\." ==============================================
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.SA 1
.TL
A Consumer Library Interface to DWARF 
.AF ""
.AU "David Anderson"
.PF "'\*(vE'- \\\\nP -''"
.AS 1
This document describes an interface to a library of functions
.FS 
UNIX is a registered trademark of UNIX System Laboratories, Inc.
in the United States and other countries.
.FE
to access DWARF debugging information entries and DWARF line number
information (and other DWARF2/3 information). 
It does not make recommendations as to how the functions
described in this document should be implemented nor does it
suggest possible optimizations. 
.P
The document is oriented to reading DWARF version 2 
and version 3.
There are certain sections which are SGI-specific (those
are clearly identified in the document).
.P
\*(vE

.AE
.MT 4

.H 1 "INTRODUCTION"
This document describes an interface to \fIlibdwarf\fP, a
library of functions to provide access to DWARF debugging information
records, DWARF line number information, DWARF address range and global 
names information, weak names information, DWARF frame description 
information, DWARF static function names, DWARF static variables, and 
DWARF type information.
.P
The document has long mentioned the  
"Unix International Programming Languages Special Interest Group" 
(PLSIG), under whose auspices the
DWARF committee was formed around 1991.
"Unix International"  
was disbanded in the 1990s and no longer exists.
.P
The DWARF committee published DWARF2 July 27, 1993.
.P
In the mid 1990s this document and the library it describes
(which the committee never endorsed, having decided
not to endorse or approve any particular library interface)
was made available on the internet by Silicon Graphics, Inc.
.P
In 2005 the DWARF committee began an affiliation with FreeStandards.org.
In 2007 FreeStandards.org merged with The Linux Foundation.
The DWARF committee dropped its affiliation with FreeStandards.org
in 2007 and established the dwarfstd.org website.
See "http://www.dwarfstd.org" for current
information on standardization activities 
and a copy of the standard.
.H 2 "Copyright"
Copyright 1993-2006 Silicon Graphics, Inc.

Copyright 2007-2011 David Anderson. 

Permission is hereby granted to 
copy or republish or use any or all of this document without
restriction except that when publishing more than a small amount
of the document
please acknowledge Silicon Graphics, Inc and David Anderson.

This document is distributed in the hope that it would be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

.H 2 "Purpose and Scope"
The purpose of this document is to document a library of functions 
to access DWARF debugging information. There is no effort made in 
this document to address the creation of these records as those
issues are addressed separately 
(see "A Producer Library Interface to DWARF").

.P
Additionally, the focus of this document is the functional interface,
and as such, implementation as well as optimization issues are
intentionally ignored.


.H 2 "Document History"
.P
A document was written about 1991 which had similar
layout and interfaces. 
Written by people from Hal Corporation,
That document described a library for reading DWARF1.
The authors distributed paper copies to the committee
with the clearly expressed intent to propose the document as
a supported interface definition.
The committee decided not to pursue a library definition.
.P
SGI wrote the document you are now reading in 1993
with a similar layout and content and organization, but 
it was complete document rewrite with the intent to read DWARF2
(the DWARF version then in existence).
The intent was (and is) to also cover
future revisions of DWARF.
All the function interfaces were changed 
in 1994 to uniformly
return a simple integer success-code (see DW_DLV_OK etc), 
generally following
the recommendations in the chapter titled "Candy Machine Interfaces"
of "Writing Solid Code", a book by
Steve Maguire (published by Microsoft Press).
.H 2 "Definitions"
DWARF debugging information entries (DIEs) are the segments of information 
placed in the \f(CW.debug_*\fP sections by compilers, assemblers, and 
linkage editors that, in conjunction with line number entries, are 
necessary for symbolic source-level debugging.  
Refer to the latest
"\fIDWARF Debugging Information Format\fP" from www.dwarfstd.org for a more 
complete description of these entries.

.P
This document adopts all the terms and definitions in "\fIDWARF Debugging 
Information Format\fP" versions 2,3, and 4.  
It originally focused on the implementation at
Silicon Graphics, Inc., but now
attempts to be more generally useful.

.H 2 "Overview"
The remaining sections of this document describe the proposed interface
to \f(CWlibdwarf\fP, first by describing the purpose of additional types
defined by the interface, followed by descriptions of the available 
operations.  This document assumes you are thoroughly familiar with the 
information contained in the \fIDWARF Debugging Information Format\fP 
document. 
.P
We separate the functions into several categories to emphasize that not 
all consumers want to use all the functions.  We call the categories 
Debugger, Internal-level, High-level, and Miscellaneous not because one is more 
important than another but as a way of making the rather large set of 
function calls easier to understand.
.P
Unless otherwise specified, all functions and structures should be
taken as being designed for Debugger consumers.
.P
The Debugger Interface of this library is intended to be used by debuggers. 
The interface is low-level (close to dwarf) but suppresses irrelevant detail.
A debugger will want to absorb all of some sections at startup and will 
want to see little or nothing of some sections except at need.  And even 
then will probably want to absorb only the information in a single compilation 
unit at a time.  A debugger does not care about
implementation details of the library.
.P
The Internal-level Interface is for a DWARF prettyprinter and checker.  
A 
thorough prettyprinter will want to know all kinds of internal things 
(like actual FORM numbers and actual offsets) so it can check for 
appropriate structure in the DWARF data and print (on request) all 
that internal information for human users and libdwarf authors and 
compiler-writers.  
Calls in this interface provide data a debugger 
does not care about.
.P
The High-level Interface is for higher level access
(it is not really a high level interface!).  
Programs such as 
disassemblers will want to be able to display relevant information 
about functions and line numbers without having to invest too much 
effort in looking at DWARF.
.P
The miscellaneous interface is just what is left over: the error handler 
functions.
.P
The following is a brief mention of the changes in this libdwarf from 
the libdwarf draft for DWARF Version 1 and recent changes.
.H 2 "Items Changed"
.P
Added new functions (some for libdwarf client code) 
and internal logic support for the 
DWARF4 .debug_types section.
The new functions are
dwarf_next_cu_header_c(),
dwarf_siblingof_b(), dwarf_offdie_b(),
dwarf_get_cu_die_offset_given_cu_header_offset_b(),
dwarf_get_die_infotypes_flag(),
dwarf_get_section_max_offsets_b().
.P
New functions and logic support additional detailed error reporting
so that more compiler bugs can be reported sensibly 
by consumer code (as opposed
to having libdwarf just assume 
things are ok and blindly continuing on
with erroneous data).
November 20, 2010
.P
It seems impossible to default to both DW_FRAME_CFA_COL
and DW_FRAME_CFA_COL3 in a single build of libdwarf,
so the default is now unambiguously DW_FRAME_CFA_COL3
unless the configure option --enable-oldframecol 
is specified at configure time.
The function dwarf_set_frame_cfa_value()
may be used to override the default : using that function gives
consumer applications full control (its use is highly
recommended). 
(January 17,2010)
.P
Added dwarf_set_reloc_application() and the default
automatic application of Elf 'rela' relocations
to DWARF sections (such rela sections appear in .o files, not
in executables or shared objects, in general).
The  dwarf_set_reloc_application() routine lets a consumer
turn off the automatic application of 'rela' relocations
if desired (it is not clear why anyone would really want to do that,
but possibly a consumer could write its own relocation application).
An example application that traverses a set of DIEs
was added to the new dwarfexample directory (not
in this libdwarf directory, but in parallel to it).
(July 10, 2009)
.P
Added dwarf_get_TAG_name() (and the FORM AT and so on)
interface functions so applications can get the string
of the TAG, Attribute, etc as needed. (June 2009)
.P
Added dwarf_get_ranges_a() and dwarf_loclist_from_expr_a()
functions which add arguments allowing a correct address_size
when the address_size varies by compilation unit (a varying
address_size is quite rare as of May 2009).
(May 2009)
.P
Added dwarf_set_frame_same_value(), and
dwarf_set_frame_undefined_value() to complete
the set of frame-information functions needed to allow
an application get all frame information
returned correctly (meaning that it
can be correctly interpreted) for all ABIs.  
Documented dwarf_set_frame_cfa_value().
Corrected spelling to dwarf_set_frame_rule_initial_value().
(April 2009).
.P
Added support for various DWARF3 features, but primarily
a new frame-information interface tailorable at run-time
to more than a single ABI.
See dwarf_set_frame_rule_initial_value(), dwarf_set_frame_rule_table_size(),
dwarf_set_frame_cfa_value().
See also dwarf_get_fde_info_for_reg3() and
dwarf_get_fde_info_for_cfa_reg3().  (April 2006)
.P
Added support for DWARF3 .debug_pubtypes section.
Corrected various leaks (revising dealloc() calls, adding
new functions) and corrected dwarf_formstring() documentation.
.P 
Added dwarf_srclines_dealloc() as the previous deallocation
method documented for data returned by
dwarf_srclines() was incapable of freeing
all the allocated storage (14 July 2005).
.P
dwarf_nextglob(), dwarf_globname(), and dwarf_globdie() were all changed 
to operate on the items in the .debug_pubnames section.
.P
All functions were modified to return solely an error code.
Data is returned through pointer arguments.
This makes writing safe and correct library-using-code far easier.
For justification for this approach, see 
the chapter titled "Candy Machine Interfaces"
in the book "Writing Solid Code" by
Steve Maguire.

.H 2 "Items Removed"
.P
Dwarf_Type
was removed since types are no longer special.
.P
dwarf_typeof()
was removed since types are no longer special.
.P
Dwarf_Ellist
was removed since element lists no longer are a special format.
.P
Dwarf_Bounds
was removed since bounds have been generalized.
.P
dwarf_nextdie()
was replaced by dwarf_next_cu_header() to reflect the
real way DWARF is organized.
The dwarf_nextdie() was only useful for getting to compilation
unit beginnings, so it does not seem harmful to remove it in favor
of a more direct function.
.P
dwarf_childcnt() is removed on grounds
that no good use was apparent.
.P
dwarf_prevline() and dwarf_nextline() were removed on grounds this
is better left to a debugger to do.
Similarly, dwarf_dieline() was removed.
.P
dwarf_is1stline() was removed as it was not meaningful for the
revised DWARF line operations.
.P
Any libdwarf implementation might well decide to support all the
removed functionality and to retain the DWARF Version 1 meanings
of that functionality.  
This would be difficult because the
original libdwarf draft
specification used traditional C library interfaces which
confuse the values returned by successful calls with
exceptional conditions like failures and 'no more data' indications.

.H 2 "Revision History"
.VL 15
.LI "October 2011"
DWARF4 support for reading .debug_types added.
.LI "March 93"
Work on DWARF2 SGI draft begins
.LI "June 94"
The function returns are changed to return an error/success code
only.
.LI "April 2006:
Support for DWARF3 consumer operations is close to completion.
.LI "November 2010:
Added various new functions and improved error checking.
.LE

.H 1 "Types Definitions"

.H 2 "General Description"
The \fIlibdwarf.h\fP header file contains typedefs and preprocessor 
definitions of types and symbolic names used to reference objects 
of \fIlibdwarf\fP. The types defined by typedefs contained in 
\fIlibdwarf.h\fP all use the convention of adding \f(CWDwarf_\fP 
as a prefix and can be placed in three categories: 

.BL
.LI
Scalar types : The scalar types defined in \fIlibdwarf.h\fP are
defined primarily for notational convenience and identification.
Depending on the individual definition, they are interpreted as a 
value, a pointer, or as a flag.
.LI
Aggregate types : Some values can not be represented by a single 
scalar type; they must be represented by a collection of, or as a 
union of, scalar and/or aggregate types. 
.LI
Opaque types : The complete definition of these types is intentionally
omitted; their use is as handles for query operations, which will yield
either an instance of another opaque type to be used in another query, or 
an instance of a scalar or aggregate type, which is the actual result.
.P

.H 2 "Scalar Types"
The following are the defined by \fIlibdwarf.h\fP:

.DS
\f(CW
typedef int                Dwarf_Bool;
typedef unsigned long long Dwarf_Off;
typedef unsigned long long Dwarf_Unsigned;
typedef unsigned short     Dwarf_Half;
typedef unsigned char      Dwarf_Small;
typedef signed long long   Dwarf_Signed;
typedef unsigned long long Dwarf_Addr;
typedef void 		   *Dwarf_Ptr;
typedef void   (*Dwarf_Handler)(Dwarf_Error *error, Dwarf_Ptr errarg);
.DE

.nr aX \n(Fg+1
Dwarf_Ptr is an address for use by the host program calling the library,
not for representing pc-values/addresses within the target object file.
Dwarf_Addr is for pc-values within the target object file.  The sample 
scalar type assignments above are for a \fIlibdwarf.h\fP that can read 
and write
32-bit or 64-bit binaries on a 32-bit or 64-bit host machine.
The types must be  defined appropriately
for each implementation of libdwarf.
A description of these scalar types in the SGI/MIPS
environment is given in Figure \n(aX.

.DS
.TS
center box, tab(:);
lfB lfB lfB lfB
l c c l.
NAME:SIZE:ALIGNMENT:PURPOSE
_
Dwarf_Bool:4:4:Boolean states
Dwarf_Off:8:8:Unsigned file offset
Dwarf_Unsigned:8:8:Unsigned large integer
Dwarf_Half:2:2:Unsigned medium integer
Dwarf_Small:1:1:Unsigned small integer
Dwarf_Signed:8:8:Signed large integer
Dwarf_Addr:8:8:Program address
:::(target program)
Dwarf_Ptr:4|8:4|8:Dwarf section pointer 
:::(host program)
Dwarf_Handler:4|8:4|8:Pointer to
:::error handler function 
.TE
.FG "Scalar Types"
.DE

.H 2 "Aggregate Types"
The following aggregate types are defined by 
\fIlibdwarf.h\fP:
\f(CWDwarf_Loc\fP,
\f(CWDwarf_Locdesc\fP,
\f(CWDwarf_Block\fP, 
\f(CWDwarf_Frame_Op\fP. 
\f(CWDwarf_Regtable\fP. 
\f(CWDwarf_Regtable3\fP. 
While most of \f(CWlibdwarf\fP acts on or returns simple values or
opaque pointer types, this small set of structures seems useful.

.H 3 "Location Record"
The \f(CWDwarf_Loc\fP type identifies a single atom of a location description
or a location expression.

.DS
\f(CWtypedef struct {
        Dwarf_Small        lr_atom;
        Dwarf_Unsigned     lr_number;
        Dwarf_Unsigned     lr_number2;
        Dwarf_Unsigned     lr_offset;  
} Dwarf_Loc;\fP
.DE

The \f(CWlr_atom\fP identifies the atom corresponding to the \f(CWDW_OP_*\fP 
definition in \fIdwarf.h\fP and it represents the operation to be performed 
in order to locate the item in question.

.P
The \f(CWlr_number\fP field is the operand to be used in the calculation
specified by the \f(CWlr_atom\fP field; not all atoms use this field.
Some atom operations imply signed numbers so it is necessary to cast 
this to a \f(CWDwarf_Signed\fP type for those operations.

.P
The \f(CWlr_number2\fP field is the second operand specified by the 
\f(CWlr_atom\fP field; only \f(CWDW_OP_BREGX\fP has this field.  Some 
atom operations imply signed numbers so it may be necessary to cast 
this to a \f(CWDwarf_Signed\fP type for those operations.
.P
For a \f(CWDW_OP_implicit_value\fP operator the \f(CWlr_number2\fP
field is a pointer to the bytes of the value. The field pointed to
is \f(CWlr_number\fP bytes long.  There is no explicit terminator.
Do not attempt to \f(CWfree\fP the bytes which \f(CWlr_number2\fP
points at and do not alter those bytes. The pointer value
remains valid till the open Dwarf_Debug is closed.
This is a rather ugly use of a host integer to hold a pointer. 
You will normally have to do a 'cast' operation to use the value. 
.P
The \f(CWlr_offset\fP field is the byte offset (within the block the 
location record came from) of the atom specified by the \f(CWlr_atom\fP 
field.  This is set on all atoms.  This is useful for operations 
\f(CWDW_OP_SKIP\fP and \f(CWDW_OP_BRA\fP.

.H 3 "Location Description"
The \f(CWDwarf_Locdesc\fP type represents an ordered list of 
\f(CWDwarf_Loc\fP records used in the calculation to locate 
an item.  Note that in many cases, the location can only be 
calculated at runtime of the associated program.

.DS
\f(CWtypedef struct {
        Dwarf_Addr        ld_lopc;
        Dwarf_Addr        ld_hipc;
        Dwarf_Unsigned    ld_cents;
        Dwarf_Loc*        ld_s;
} Dwarf_Locdesc;\fP
.DE

The \f(CWld_lopc\fP and \f(CWld_hipc\fP fields provide an address range for
which this location descriptor is valid.  Both of these fields are set to
\fIzero\fP if the location descriptor is valid throughout the scope of the
item it is associated with.  These addresses are virtual memory addresses, 
not offsets-from-something.  The virtual memory addresses do not account 
for dso movement (none of the pc values from libdwarf do that, it is up to 
the consumer to do that).

.P
The \f(CWld_cents\fP field contains a count of the number of \f(CWDwarf_Loc\fP 
entries pointed to by the \f(CWld_s\fP field.

.P
The \f(CWld_s\fP field points to an array of \f(CWDwarf_Loc\fP records. 

.H 3 "Data Block"
.SP
The \f(CWDwarf_Block\fP type is used to contain the value of an attribute
whose form is either \f(CWDW_FORM_block1\fP, \f(CWDW_FORM_block2\fP, 
\f(CWDW_FORM_block4\fP, \f(CWDW_FORM_block8\fP, or \f(CWDW_FORM_block\fP.
Its intended use is to deliver the value for an attribute of any of these 
forms.

.DS
\f(CWtypedef struct {
        Dwarf_Unsigned     bl_len;
        Dwarf_Ptr          bl_data;
} Dwarf_Block;\fP
.DE

.P
The \f(CWbl_len\fP field contains the length in bytes of the data pointed
to by the \f(CWbl_data\fP field. 

.P
The \f(CWbl_data\fP field contains a pointer to the uninterpreted data.
Since we use  a \f(CWDwarf_Ptr\fP here one must copy the pointer to some 
other type (typically an \f(CWunsigned char *\fP) so one can add increments 
to index through the data.  The data pointed to by \f(CWbl_data\fP is not 
necessarily at any useful alignment.

.H 3 "Frame Operation Codes: DWARF 2"
This interface is adequate for DWARF2 but not for DWARF3.
A separate interface usable for DWARF3 and for DWARF2 is described below.
This interface is deprecated. Use the interface for DWARF3 and DWARF2.
See also the section "Low Level Frame Operations" below.
.P
The DWARF2 \f(CWDwarf_Frame_Op\fP type is used to contain the data of a single
instruction of an instruction-sequence of low-level information from the 
section containing frame information.  This is ordinarily used by 
Internal-level Consumers trying to print everything in detail.

.DS
\f(CWtypedef struct {
	Dwarf_Small  fp_base_op;
	Dwarf_Small  fp_extended_op;
	Dwarf_Half   fp_register;
	Dwarf_Signed fp_offset;
	Dwarf_Offset fp_instr_offset;
} Dwarf_Frame_Op;
.DE

\f(CWfp_base_op\fP is the 2-bit basic op code.  \f(CWfp_extended_op\fP is 
the 6-bit extended opcode (if \f(CWfp_base_op\fP indicated there was an 
extended op code) and is zero otherwise.
.P
\f(CWfp_register\fP 
is any (or the first) register value as defined
in the \f(CWCall Frame Instruction Encodings\fP figure
in the \f(CWdwarf\fP document.
If not used with the Op it is 0.
.P
\f(CWfp_offset\fP
is the address, delta, offset, or second register as defined
in the \f(CWCall Frame Instruction Encodings\fP figure
in the \f(CWdwarf\fP document.
If this is an \f(CWaddress\fP then the value should be cast to
\f(CW(Dwarf_Addr)\fP before being used.
In any implementation this field *must* be as large as the
larger of Dwarf_Signed and Dwarf_Addr for this to work properly.
If not used with the op it is 0.
.P
\f(CWfp_instr_offset\fP is the byte_offset (within the instruction
stream of the frame instructions) of this operation.  It starts at 0
for a given frame descriptor.

.H 3 "Frame Regtable: DWARF 2"
This interface is adequate for DWARF2 
and MIPS but not for DWARF3.
A separate and preferred interface usable for DWARF3 and for DWARF2
is described below.
See also the section "Low Level Frame Operations" below.
.P
The \f(CWDwarf_Regtable\fP type is used to contain the 
register-restore information for all registers at a given
PC value.
Normally used by debuggers.
If you wish to default to this interface and to the use
of DW_FRAME_CFA_COL, specify --enable_oldframecol
at libdwarf configure time.
Or add a call dwarf_set_frame_cfa_value(dbg,DW_FRAME_CFA_COL)
after your dwarf_init() call, this call replaces the 
default libdwarf-compile-time value with DW_FRAME_CFA_COL.
.DS
/* DW_REG_TABLE_SIZE must reflect the number of registers
 *(DW_FRAME_LAST_REG_NUM) as defined in dwarf.h
 */
#define DW_REG_TABLE_SIZE  <fill in size here, 66 for MIPS/IRIX>
\f(CWtypedef struct {
    struct {
        Dwarf_Small         dw_offset_relevant;
        Dwarf_Half          dw_regnum;
        Dwarf_Addr          dw_offset;
    }                       rules[DW_REG_TABLE_SIZE];
} Dwarf_Regtable;\fP
.DE
.P
The array is indexed by register number.
The field values for each index are described next.
For clarity we describe the field values for index rules[M]
(M being any legal array element index).
.P
\f(CWdw_offset_relevant\fP is non-zero to indicate the \f(CWdw_offset\fP
field is meaningful. If zero then the \f(CWdw_offset\fP is zero
and should be ignored.
.P
\f(CWdw_regnum \fPis the register number applicable.
If \f(CWdw_offset_relevant\fP is zero, then this is the register
number of the register containing the value for register M.
If \f(CWdw_offset_relevant\fP is non-zero, then this is
the register number of the register to use as a base (M may be
DW_FRAME_CFA_COL, for example) and the \f(CWdw_offset\fP
value applies.  The value of register M is therefore
the value of register \f(CWdw_regnum\fP.
.P
\f(CWdw_offset\fP should be ignored if \f(CWdw_offset_relevant\fP is zero.
If \f(CWdw_offset_relevant\fP is non-zero, then 
the consumer code should add the value to
the value of the register \f(CWdw_regnum\fP to produce the
value.  

.H 3 "Frame Operation Codes: DWARF 3 (and DWARF2)"
This interface is adequate for DWARF3 and for DWARF2 (and DWARF4).
It is new in libdwarf in April 2006.
See also the section "Low Level Frame Operations" below.
.P
The DWARF2 \f(CWDwarf_Frame_Op3\fP type is used to contain the data of a single
instruction of an instruction-sequence of low-level information from the 
section containing frame information.  This is ordinarily used by 
Internal-level Consumers trying to print everything in detail.

.DS
\f(CWtypedef struct {
        Dwarf_Small     fp_base_op;
        Dwarf_Small     fp_extended_op;
        Dwarf_Half      fp_register;

        /* Value may be signed, depends on op.
           Any applicable data_alignment_factor has
           not been applied, this is the  raw offset. */
        Dwarf_Unsigned  fp_offset_or_block_len;
        Dwarf_Small     *fp_expr_block;

        Dwarf_Off       fp_instr_offset;
} Dwarf_Frame_Op3;\fP
.DE

\f(CWfp_base_op\fP is the 2-bit basic op code.  \f(CWfp_extended_op\fP is 
the 6-bit extended opcode (if \f(CWfp_base_op\fP indicated there was an 
extended op code) and is zero otherwise.
.P
\f(CWfp_register\fP 
is any (or the first) register value as defined
in the \f(CWCall Frame Instruction Encodings\fP figure
in the \f(CWdwarf\fP document.
If not used with the Op it is 0.
.P
\f(CWfp_offset_or_block_len\fP
is the address, delta, offset, or second register as defined
in the \f(CWCall Frame Instruction Encodings\fP figure
in the \f(CWdwarf\fP document. Or (depending on the op, it
may be the length of the dwarf-expression block pointed to
by \f(CWfp_expr_block\fP.
If this is an \f(CWaddress\fP then the value should be cast to
\f(CW(Dwarf_Addr)\fP before being used.
In any implementation this field *must* be as large as the
larger of Dwarf_Signed and Dwarf_Addr for this to work properly.
If not used with the op it is 0.
.P
\f(CWfp_expr_block\fP (if applicable to the op)
points to a dwarf-expression block which is \f(CWfp_offset_or_block_len\fP
bytes long.
.P
\f(CWfp_instr_offset\fP is the byte_offset (within the instruction
stream of the frame instructions) of this operation.  It starts at 0
for a given frame descriptor.

.H 3 "Frame Regtable: DWARF 3"
This interface is adequate for DWARF3 and for DWARF2.
It is new in libdwarf as of April 2006.
The default configure of libdwarf 
inserts DW_FRAME_CFA_COL3 as the default CFA column.
Or add a call dwarf_set_frame_cfa_value(dbg,DW_FRAME_CFA_COL3)
after your dwarf_init() call, this call replaces the 
default libdwarf-compile-time value with DW_FRAME_CFA_COL3.
.P
The \f(CWDwarf_Regtable3\fP type is used to contain the 
register-restore information for all registers at a given
PC value.
Normally used by debuggers.
.DS
\f(CWtypedef struct Dwarf_Regtable_Entry3_s {
        Dwarf_Small         dw_offset_relevant;
        Dwarf_Small         dw_value_type;
        Dwarf_Half          dw_regnum;
        Dwarf_Unsigned      dw_offset_or_block_len;
        Dwarf_Ptr           dw_block_ptr;
}Dwarf_Regtable_Entry3;

typedef struct Dwarf_Regtable3_s {
    struct Dwarf_Regtable_Entry3_s   rt3_cfa_rule;

    Dwarf_Half                       rt3_reg_table_size;
    struct Dwarf_Regtable_Entry3_s * rt3_rules;
} Dwarf_Regtable3;\fP

.DE
.P
The array is indexed by register number.
The field values for each index are described next.
For clarity we describe the field values for index rules[M]
(M being any legal array element index).
(DW_FRAME_CFA_COL3  DW_FRAME_SAME_VAL, DW_FRAME_UNDEFINED_VAL
are not legal array indexes, nor is any index < 0 or >=
rt3_reg_table_size);
The caller  of routines using this
struct must create data space for rt3_reg_table_size entries
of struct Dwarf_Regtable_Entry3_s and arrange that
rt3_rules points to that space and that rt3_reg_table_size
is set correctly.  The caller need not (but may)
initialize the contents of the rt3_cfa_rule or the rt3_rules array.
The following applies to each rt3_rules rule M:
.P
.in +4
\f(CWdw_regnum\fP is the register number applicable.
If \f(CWdw_regnum\fP is DW_FRAME_UNDEFINED_VAL, then the
register I has undefined value.
If \f(CWdw_regnum\fP is DW_FRAME_SAME_VAL, then the
register I has the same value as in the previous frame.
.P
If \f(CWdw_regnum\fP is neither of these two, then the following apply:
.P
.P
\f(CWdw_value_type\fP determines the meaning of the other fields.
It is one of DW_EXPR_OFFSET (0),
DW_EXPR_VAL_OFFSET(1), DW_EXPR_EXPRESSION(2) or 
DW_EXPR_VAL_EXPRESSION(3).

.P
If \f(CWdw_value_type\fP is DW_EXPR_OFFSET (0) then
this is as in DWARF2 and the offset(N) rule  or the register(R)
rule
of the DWARF3 and DWARF2 document applies.
The value is either:
.in +4
If \f(CWdw_offset_relevant\fP is non-zero, then \f(CWdw_regnum\fP  
is effectively ignored but must be identical to
DW_FRAME_CFA_COL3 (and the \f(CWdw_offset\fP value applies. 
The value of register M is therefore
the value of CFA plus the value
of \f(CWdw_offset\fP.   The result of the calculation
is the address in memory where the value of register M resides.
This is the offset(N) rule of the DWARF2 and DWARF3 documents.
.P
\f(CWdw_offset_relevant\fP is zero it indicates the \f(CWdw_offset\fP
field is not meaningful. 
The value of register M is 
the value currently in register \f(CWdw_regnum\fP (the
value DW_FRAME_CFA_COL3 must not appear, only real registers).
This is the register(R) rule of the DWARF3 spec.
.in -4

.P
If \f(CWdw_value_type\fP is DW_EXPR_OFFSET (1) then
this is the the val_offset(N) rule of the DWARF3 spec applies.
The calculation is identical to that of DW_EXPR_OFFSET (0) 
but the value is interpreted as the value of register M
(rather than the address where register M's value is stored).
.P
If \f(CWdw_value_type\fP is DW_EXPR_EXPRESSION (2) then
this is the the expression(E) rule of the DWARF3 document.
.P
.in +4
\f(CWdw_offset_or_block_len\fP is the length in bytes of
the in-memory block  pointed at by \f(CWdw_block_ptr\fP.
\f(CWdw_block_ptr\fP is a DWARF expression.
Evaluate that expression and the result is the address
where the previous value of register M is found.
.in -4
.P
If \f(CWdw_value_type\fP is DW_EXPR_VAL_EXPRESSION (3) then
this is the the val_expression(E) rule of the DWARF3 spec.
.P
.in +4
\f(CWdw_offset_or_block_len\fP is the length in bytes of
the in-memory block  pointed at by \f(CWdw_block_ptr\fP.
\f(CWdw_block_ptr\fP is a DWARF expression.
Evaluate that expression and the result is the 
previous value of register M.
.in -4
.P
The rule \f(CWrt3_cfa_rule\fP is the current value of
the CFA. It is interpreted exactly like
any register M rule (as described just above) except that 
\f(CWdw_regnum\fP cannot be CW_FRAME_CFA_REG3 or
DW_FRAME_UNDEFINED_VAL or DW_FRAME_SAME_VAL but must
be a real register number.
.in -4



.H 3 "Macro Details Record"
The \f(CWDwarf_Macro_Details\fP type gives information about
a single entry in the .debug.macinfo section.
.DS
\f(CWstruct Dwarf_Macro_Details_s {
  Dwarf_Off    dmd_offset;
  Dwarf_Small  dmd_type;  
  Dwarf_Signed dmd_lineno;
  Dwarf_Signed dmd_fileindex;
  char *       dmd_macro;
};
typedef struct Dwarf_Macro_Details_s Dwarf_Macro_Details;
.DE
.P
\f(CWdmd_offset\fP is the byte offset, within the .debug_macinfo
section, of this macro information.
.P
\f(CWdmd_type\fP is the type code of this macro info entry
(or 0, the type code indicating that this is the end of
macro information entries for a compilation unit.
See \f(CWDW_MACINFO_define\fP, etc in the DWARF document.
.P
\f(CWdmd_lineno\fP is the line number where this entry was found,
or 0 if there is no applicable line number.
.P
\f(CWdmd_fileindex\fP is the file index of the file involved.
This is only guaranteed meaningful on a \f(CWDW_MACINFO_start_file\fP
\f(CWdmd_type\fP.  Set to -1 if unknown (see the functional
interface for more details).
.P
\f(CWdmd_macro\fP is the applicable string.
For a \f(CWDW_MACINFO_define\fP
this is the macro name and value.
For a
\f(CWDW_MACINFO_undef\fP, or
this is the macro name.
For a
\f(CWDW_MACINFO_vendor_ext\fP
this is the vendor-defined string value.
For other \f(CWdmd_type\fPs this is 0.

.H 2 "Opaque Types"
The opaque types declared in \fIlibdwarf.h\fP are used as descriptors
for queries against DWARF information stored in various debugging 
sections.  Each time an instance of an opaque type is returned as a 
result of a \fIlibdwarf\fP operation (\f(CWDwarf_Debug\fP excepted), 
it should be freed, using \f(CWdwarf_dealloc()\fP when it is no longer 
of use (read the following documentation for details, as in at least
one case there is a special routine provided for deallocation
and \f(CWdwarf_dealloc()\fP is not directly called: 
see \f(CWdwarf_srclines()\fP).
Some functions return a number of instances of an opaque type 
in a block, by means of a pointer to the block and a count of the number
of opaque descriptors in the block:
see the function description for deallocation rules for such functions.
The list of opaque types defined 
in \fIlibdwarf.h\fP that are pertinent to the Consumer Library, and their 
intended use is described below.

.DS
\f(CWtypedef struct Dwarf_Debug_s* Dwarf_Debug;\fP
.DE
An instance of the \f(CWDwarf_Debug\fP type is created as a result of a 
successful call to \f(CWdwarf_init()\fP, or \f(CWdwarf_elf_init()\fP, 
and is used as a descriptor for subsequent access to most \f(CWlibdwarf\fP
functions on that object.  The storage pointed to by this descriptor 
should be not be freed, using the \f(CWdwarf_dealloc()\fP function.
Instead free it with \f(CWdwarf_finish()\fP.
.P

.DS
\f(CWtypedef struct Dwarf_Die_s* Dwarf_Die;\fP
.DE
An instance of a \f(CWDwarf_Die\fP type is returned from a successful 
call to the \f(CWdwarf_siblingof()\fP, \f(CWdwarf_child\fP, or 
\f(CWdwarf_offdie_b()\fP function, and is used as a descriptor for queries 
about information related to that DIE.  The storage pointed to by this 
descriptor should be freed, using \f(CWdwarf_dealloc()\fP with the allocation 
type \f(CWDW_DLA_DIE\fP when no longer needed.

.DS
\f(CWtypedef struct Dwarf_Line_s* Dwarf_Line;\fP
.DE
Instances of \f(CWDwarf_Line\fP type are returned from a successful call 
to the \f(CWdwarf_srclines()\fP function, and are used as descriptors for 
queries about source lines.  The storage pointed to by these descriptors
should be individually freed, using \f(CWdwarf_dealloc()\fP with the 
allocation type \f(CWDW_DLA_LINE\fP when no longer needed.

.DS
\f(CWtypedef struct Dwarf_Global_s* Dwarf_Global;\fP
.DE
Instances of \f(CWDwarf_Global\fP type are returned from a successful 
call to the \f(CWdwarf_get_globals()\fP function, and are used as 
descriptors for queries about global names (pubnames).

.DS
\f(CWtypedef struct Dwarf_Weak_s* Dwarf_Weak;\fP
.DE
Instances of \f(CWDwarf_Weak\fP type are returned from a successful call 
to the 
SGI-specific \f(CWdwarf_get_weaks()\fP
function, and are used as descriptors for 
queries about weak names.  The storage pointed to by these descriptors 
should be individually freed, using \f(CWdwarf_dealloc()\fP with the 
allocation type 
\f(CWDW_DLA_WEAK_CONTEXT\fP 
(or
\f(CWDW_DLA_WEAK\fP, an older name, supported for compatibility)
when no longer needed.

.DS
\f(CWtypedef struct Dwarf_Func_s* Dwarf_Func;\fP
.DE
Instances of \f(CWDwarf_Func\fP type are returned from a successful
call to the 
SGI-specific \f(CWdwarf_get_funcs()\fP
function, and are used as 
descriptors for queries about static function names.  

.DS
\f(CWtypedef struct Dwarf_Type_s* Dwarf_Type;\fP
.DE
Instances of \f(CWDwarf_Type\fP type are returned from a successful call 
to the 
SGI-specific \f(CWdwarf_get_types()\fP
function, and are used as descriptors for 
queries about user defined types.  

.DS
\f(CWtypedef struct Dwarf_Var_s* Dwarf_Var;\fP
.DE
Instances of \f(CWDwarf_Var\fP type are returned from a successful call 
to the SGI-specific \f(CWdwarf_get_vars()\fP
function, and are used as descriptors for 
queries about static variables.  

.DS
\f(CWtypedef struct Dwarf_Error_s* Dwarf_Error;\fP
.DE
This descriptor points to a structure that provides detailed information
about errors detected by \f(CWlibdwarf\fP.  Users typically provide a
location for \f(CWlibdwarf\fP to store this descriptor for the user to
obtain more information about the error.  The storage pointed to by this
descriptor should be freed, using \f(CWdwarf_dealloc()\fP with the 
allocation type \f(CWDW_DLA_ERROR\fP when no longer needed.

.DS
\f(CWtypedef struct Dwarf_Attribute_s* Dwarf_Attribute;\fP
.DE
Instances of \f(CWDwarf_Attribute\fP type are returned from a successful 
call to the \f(CWdwarf_attrlist()\fP, or \f(CWdwarf_attr()\fP functions, 
and are used as descriptors for queries about attribute values.  The storage 
pointed to by this descriptor should be individually freed, using 
\f(CWdwarf_dealloc()\fP with the allocation type \f(CWDW_DLA_ATTR\fP when 
no longer needed.

.DS
\f(CWtypedef struct Dwarf_Abbrev_s* Dwarf_Abbrev;\fP
.DE
An instance of a \f(CWDwarf_Abbrev\fP type is returned from a successful 
call to \f(CWdwarf_get_abbrev()\fP, and is used as a descriptor for queries 
about abbreviations in the .debug_abbrev section.  The storage pointed to 
by this descriptor should be freed, using \f(CWdwarf_dealloc()\fP with the
allocation type \f(CWDW_DLA_ABBREV\fP when no longer needed.

.DS
\f(CWtypedef struct Dwarf_Fde_s* Dwarf_Fde;\fP
.DE
Instances of \f(CWDwarf_Fde\fP type are returned from a successful call 
to the \f(CWdwarf_get_fde_list()\fP, \f(CWdwarf_get_fde_for_die()\fP, or
\f(CWdwarf_get_fde_at_pc()\fP functions, and are used as descriptors for 
queries about frames descriptors.

.DS
\f(CWtypedef struct Dwarf_Cie_s* Dwarf_Cie;\fP
.DE
Instances of \f(CWDwarf_Cie\fP type are returned from a successful call 
to the \f(CWdwarf_get_fde_list()\fP function, and are used as descriptors 
for queries about information that is common to several frames.

.DS
\f(CWtypedef struct Dwarf_Arange_s* Dwarf_Arange;\fP
.DE
Instances of \f(CWDwarf_Arange\fP type are returned from successful calls 
to the \f(CWdwarf_get_aranges()\fP, or \f(CWdwarf_get_arange()\fP functions, 
and are used as descriptors for queries about address ranges.  The storage 
pointed to by this descriptor should be individually freed, using 
\f(CWdwarf_dealloc()\fP with the allocation type \f(CWDW_DLA_ARANGE\fP when 
no longer needed.

.H 1 "Error Handling"
The method for detection and disposition of error conditions that arise 
during access of debugging information via \fIlibdwarf\fP is consistent
across all \fIlibdwarf\fP functions that are capable of producing an
error.  This section describes the method used by \fIlibdwarf\fP in
notifying client programs of error conditions. 

.P
Most functions within \fIlibdwarf\fP accept as an argument a pointer to 
a \f(CWDwarf_Error\fP descriptor where a \f(CWDwarf_Error\fP descriptor 
is stored if an error is detected by the function.  Routines in the client 
program that provide this argument can query the \f(CWDwarf_Error\fP 
descriptor to determine the nature of the error and perform appropriate 
processing. 

.P
A client program can also specify a function to be invoked upon detection 
of an error at the time the library is initialized (see \f(CWdwarf_init()\fP). 
When a \fIlibdwarf\fP routine detects an error, this function is called
with two arguments: a code indicating the nature of the error and a pointer
provided by the client at initialization (again see \f(CWdwarf_init()\fP).
This pointer argument can be used to relay information between the error 
handler and other routines of the client program.  A client program can 
specify or change both the error handling function and the pointer argument 
after initialization using \f(CWdwarf_seterrhand()\fP and 
\f(CWdwarf_seterrarg()\fP.

.P
In the case where \fIlibdwarf\fP functions are not provided a pointer
to a \f(CWDwarf_Error\fP descriptor, and no error handling function was 
provided at initialization, \fIlibdwarf\fP functions terminate execution 
by calling \f(CWabort(3C)\fP.

.P
The following lists the processing steps taken upon detection of an
error:
.AL 1
.LI
Check the \f(CWerror\fP argument; if not a \fINULL\fP pointer, allocate
and initialize a \f(CWDwarf_Error\fP descriptor with information describing
the error, place this descriptor in the area pointed to by \f(CWerror\fP,
and return a value indicating an error condition.
.LI
If an \f(CWerrhand\fP argument was provided to \f(CWdwarf_init()\fP
at initialization, call \f(CWerrhand()\fP passing it the error descriptor
and the value of the \f(CWerrarg\fP argument provided to \f(CWdwarf_init()\fP. 
If the error handling function returns, return a value indicating an 
error condition.
.LI
Terminate program execution by calling \f(CWabort(3C)\fP.
.LE
.SP

In all cases, it is clear from the value returned from a function 
that an error occurred in executing the function, since
DW_DLV_ERROR is returned.
.P
As can be seen from the above steps, the client program can provide
an error handler at initialization, and still provide an \f(CWerror\fP
argument to \fIlibdwarf\fP functions when it is not desired to have
the error handler invoked.

.P
If a \f(CWlibdwarf\fP function is called with invalid arguments, the 
behavior is undefined.  In particular, supplying a \f(CWNULL\fP pointer 
to a \f(CWlibdwarf\fP function (except where explicitly permitted), 
or pointers to invalid addresses or uninitialized data causes undefined 
behavior; the return value in such cases is undefined, and the function 
may fail to invoke the caller supplied error handler or to return a 
meaningful error number.  Implementations also may abort execution for 
such cases.

.P
Some errors are so inconsequential that it does not warrant
rejecting an object or returning an error.
An example would be a frame length not being a multiple of
an address-size (right now this is the only such inconsequential
error).  To make it possible for a client  to report such errors
the function \f(CWdwarf_get_harmless_error_list\fP
returns strings with error text in them.  This function
may be ignored if client code does not want to bother with
such error reporting. See \f(CWDW_DLE_DEBUG_FRAME_LENGTH_NOT_MULTIPLE\fP
in the libdwarf source code.

.P
.H 2 "Returned values in the functional interface"
Values returned by \f(CWlibdwarf\fP functions to indicate 
success and errors
.nr aX \n(Fg+1
are enumerated in Figure \n(aX.
The \f(CWDW_DLV_NO_ENTRY\fP
case is useful for functions 
need to indicate that while there was no data to return
there was no error either.
For example, \f(CWdwarf_siblingof()\fP
may return \f(CWDW_DLV_NO_ENTRY\fP to indicate that that there was
no sibling to return.
.DS
.TS
center box, tab(:);
lfB cfB lfB 
l c l.
SYMBOLIC NAME:VALUE:MEANING
_
DW_DLV_ERROR:1:Error
DW_DLV_OK:0:Successful call
DW_DLV_NO_ENTRY:-1:No applicable value
.TE
.FG "Error Indications"
.DE
.P
Each function in the interface that returns a value returns one
of the integers in the above figure.
.P
If \f(CWDW_DLV_ERROR\fP is returned and a pointer to a \f(CWDwarf_Error\fP
pointer is passed to the function, then a Dwarf_Error handle is returned
through the pointer. No other pointer value in the interface returns a value.
After the \f(CWDwarf_Error\fP is no longer of interest,
a  \f(CWdwarf_dealloc(dbg,dw_err,DW_DLA_ERROR)\fP on the error
pointer is appropriate to free any space used by the error information.
.P
If \f(CWDW_DLV_NO_ENTRY\fP is returned no pointer value in the
interface returns a value.
.P
If \f(CWDW_DLV_OK\fP is returned, the \f(CWDwarf_Error\fP pointer, if
supplied, is not touched, but any other values to be returned
through pointers are returned.
In this case calls (depending on the exact function
returning the error) to \f(CWdwarf_dealloc()\fP may be appropriate
once the particular pointer returned is no longer of interest.
.P
Pointers passed to allow values to be returned through them are 
uniformly the last pointers
in each argument list.
.P
All the interface functions are defined from the point of view of
the writer-of-the-library (as is traditional for UN*X library
documentation), not from the point of view of the user of the library.
The caller might code:
.P
.DS
\f(CWDwarf_Line line;
Dwarf_Signed ret_loff;
Dwarf_Error  err;
int retval = dwarf_lineoff(line,&ret_loff,&err);\fP
.DE
for the function defined as
.P
.DS
\f(CWint dwarf_lineoff(Dwarf_Line line,Dwarf_Signed *return_lineoff,
  Dwarf_Error* err);\fP
.DE
and this document refers to the function as 
returning the value through *err or *return_lineoff or 
uses the phrase "returns in
the location pointed to by err".
Sometimes other similar phrases are used.

.H 1 "Memory Management"
Several of the functions that comprise \fIlibdwarf\fP return pointers 
(opaque descriptors) to structures that have been dynamically allocated 
by the library.  To aid in the management of dynamic memory, the function 
\f(CWdwarf_dealloc()\fP is provided to free storage allocated as a result 
of a call to a \fIlibdwarf\fP function.  This section describes the strategy 
that should be taken by a client program in managing dynamic storage.

.H 2 "Read-only Properties"
All pointers (opaque descriptors) returned by or as a result of a 
\fIlibdwarf Consumer Library\fP 
call should be assumed to point to read-only memory.  
The results are undefined for \fIlibdwarf\fP  clients that attempt 
to write to a region pointed to by a value returned by a 
\fIlibdwarf Consumer Library\fP 
call.

.H 2 "Storage Deallocation"
See the section "Returned values in the functional interface",
above, for the general rules where 
calls to \f(CWdwarf_dealloc()\fP
is appropriate.
.P
In some cases the pointers returned by a \fIlibdwarf\fP call are pointers
to data which is not freeable.  
The library knows from the allocation type
provided to it whether the space is freeable or not and will not free 
inappropriately when \f(CWdwarf_dealloc()\fP is called.  
So it is vital
that \f(CWdwarf_dealloc()\fP be called with the proper allocation type.
.P
For most storage allocated by \fIlibdwarf\fP, the client can free the
storage for reuse by calling \f(CWdwarf_dealloc()\fP, providing it with 
the \f(CWDwarf_Debug\fP descriptor specifying the object for which the
storage was allocated, a pointer to the area to be free-ed, and an 
identifier that specifies what the pointer points to (the allocation
type).  For example, to free a \f(CWDwarf_Die die\fP belonging the the
object represented by \f(CWDwarf_Debug dbg\fP, allocated by a call to 
\f(CWdwarf_siblingof()\fP, the call to \f(CWdwarf_dealloc()\fP would be:
.DS
    \f(CWdwarf_dealloc(dbg, die, DW_DLA_DIE);\fP
.DE

To free storage allocated in the form of a list of pointers (opaque 
descriptors), each member of the list should be deallocated, followed 
by deallocation of the actual list itself.  The following code fragment 
uses an invocation of \f(CWdwarf_attrlist()\fP as an example to illustrate 
a technique that can be used to free storage from any \fIlibdwarf\fP 
routine that returns a list:
.DS
\f(CWDwarf_Unsigned atcnt;
Dwarf_Attribute *atlist;
int errv;

errv = dwarf_attrlist(somedie, &atlist,&atcnt, &error);
if (errv == DW_DLV_OK) {

        for (i = 0; i < atcnt; ++i) {
                /* use atlist[i] */
                dwarf_dealloc(dbg, atlist[i], DW_DLA_ATTR);
        }
        dwarf_dealloc(dbg, atlist, DW_DLA_LIST);
}\fP
.DE

The \f(CWDwarf_Debug\fP returned from \f(CWdwarf_init()\fP 
or \f(CWdwarf_elf_init()\fP 
cannot be freed using \f(CWdwarf_dealloc()\fP.
The function \f(CWdwarf_finish()\fP will deallocate all dynamic storage
associated with an instance of a \f(CWDwarf_Debug\fP type.  In particular,
it will deallocate all dynamically allocated space associated with the
\f(CWDwarf_Debug\fP descriptor, and finally make the descriptor invalid.

An \f(CWDwarf_Error\fP returned from \f(CWdwarf_init()\fP
or \f(CWdwarf_elf_init()\fP
in case of a failure cannot be freed
using \f(CWdwarf_dealloc()\fP.
The only way to free the \f(CWDwarf_Error\fP from either of those
calls is to use \f2free(3)\fP directly.
Every \f(CWDwarf_Error\fP must be freed 
by \f(CWdwarf_dealloc()\fP except those
returned by \f(CWdwarf_init()\fP
or \f(CWdwarf_elf_init()\fP.

.P
The codes that identify the storage pointed to in calls to 
.nr aX \n(Fg+1
\f(CWdwarf_dealloc()\fP are described in figure \n(aX.
.DS
.TS
center box, tab(:);
lfB lfB 
l l.
IDENTIFIER:USED TO FREE 
_
DW_DLA_STRING           :     char* 
DW_DLA_LOC              :     Dwarf_Loc 
DW_DLA_LOCDESC          :     Dwarf_Locdesc 
DW_DLA_ELLIST           :     Dwarf_Ellist (not used)
DW_DLA_BOUNDS           :     Dwarf_Bounds (not used) 
DW_DLA_BLOCK            :     Dwarf_Block 
DW_DLA_DEBUG            :     Dwarf_Debug (do not use)
DW_DLA_DIE              :     Dwarf_Die
DW_DLA_LINE             :     Dwarf_Line 
DW_DLA_ATTR             :     Dwarf_Attribute 
DW_DLA_TYPE             :     Dwarf_Type  (not used) 
DW_DLA_SUBSCR           :     Dwarf_Subscr (not used) 
DW_DLA_GLOBAL_CONTEXT   :     Dwarf_Global 
DW_DLA_ERROR            :     Dwarf_Error 
DW_DLA_LIST             :     a list of opaque descriptors
DW_DLA_LINEBUF          :     Dwarf_Line* (not used) 
DW_DLA_ARANGE           :     Dwarf_Arange 
DW_DLA_ABBREV           :     Dwarf_Abbrev 
DW_DLA_FRAME_OP         :     Dwarf_Frame_Op 
DW_DLA_CIE              :     Dwarf_Cie 
DW_DLA_FDE              :     Dwarf_Fde
DW_DLA_LOC_BLOCK        :     Dwarf_Loc Block
DW_DLA_FRAME_BLOCK      :     Dwarf_Frame Block (not used) 
DW_DLA_FUNC_CONTEXT     :     Dwarf_Func 
DW_DLA_TYPENAME_CONTEXT :     Dwarf_Type
DW_DLA_VAR_CONTEXT      :     Dwarf_Var
DW_DLA_WEAK_CONTEXT	:     Dwarf_Weak
DW_DLA_PUBTYPES_CONTEXT	:     Dwarf_Pubtype
.TE
.FG "Allocation/Deallocation Identifiers"
.DE

.P
.H 1 "Functional Interface"
This section describes the functions available in the \fIlibdwarf\fP
library.  Each function description includes its definition, followed 
by one or more paragraph describing the function's operation.

.P
The following sections describe these functions.

.H 2 "Initialization Operations"
These functions are concerned with preparing an object file for subsequent
access by the functions in \fIlibdwarf\fP and with releasing allocated
resources when access is complete. 

.H 3 "dwarf_init()"

.DS
\f(CWint dwarf_init(
        int fd,
        Dwarf_Unsigned access,
        Dwarf_Handler errhand, 
        Dwarf_Ptr errarg,
	Dwarf_Debug * dbg,
        Dwarf_Error *error)\fP
.DE
When it returns \f(CWDW_DLV_OK\fP,
the function \f(CWdwarf_init()\fP returns through
\f(CWdbg\fP a \f(CWDwarf_Debug\fP descriptor 
that represents a handle for accessing debugging records associated with 
the open file descriptor \f(CWfd\fP.  
\f(CWDW_DLV_NO_ENTRY\fP is returned if the object
does not contain DWARF debugging information.
\f(CWDW_DLV_ERROR\fP is returned if
an error occurred.
The 
\f(CWaccess\fP argument indicates what access is allowed for the section. 
The \f(CWDW_DLC_READ\fP parameter is valid
for read access (only read access is defined or discussed in this
document).  
The \f(CWerrhand\fP 
argument is a pointer to a function that will be invoked whenever an error 
is detected as a result of a \fIlibdwarf\fP operation.  The \f(CWerrarg\fP 
argument is passed as an argument to the \f(CWerrhand\fP function.  
The file 
descriptor associated with the \f(CWfd\fP argument must refer to an ordinary 
file (i.e. not a pipe, socket, device, /proc entry, etc.), be opened with 
the at least as much permission as specified by the \f(CWaccess\fP argument, 
and cannot be closed or used as an argument to any system calls by the 
client until after \f(CWdwarf_finish()\fP is called.  
The seek position of 
the file associated with \f(CWfd\fP is undefined upon return of 
\f(CWdwarf_init()\fP.

With SGI IRIX, by default it is allowed that the app
\f(CWclose()\fP \f(CWfd\fP immediately after calling \f(CWdwarf_init()\fP,
but that is not  a portable approach (that it
works is an accidental
side effect of the fact that SGI IRIX uses \f(CWELF_C_READ_MMAP\fP 
in its hidden internal call to \f(CWelf_begin()\fP).
The portable approach is to consider that \f(CWfd\fP
must be left open till after the corresponding dwarf_finish() call
has returned.

Since \f(CWdwarf_init()\fP uses the same error handling processing as other 
\fIlibdwarf\fP functions (see \fIError Handling\fP above), client programs 
will generally supply an \f(CWerror\fP parameter to bypass the default actions 
during initialization unless the default actions are appropriate. 

.H 3 "dwarf_elf_init()"
.DS
\f(CWint dwarf_elf_init(
        Elf * elf_file_pointer,
        Dwarf_Unsigned access,
        Dwarf_Handler errhand, 
        Dwarf_Ptr errarg,
	Dwarf_Debug * dbg,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_elf_init()\fP is identical to \f(CWdwarf_init()\fP 
except that an open \f(CWElf *\fP pointer is passed instead of a file 
descriptor.  
In systems supporting \f(CWELF\fP object files this may be 
more space or time-efficient than using \f(CWdwarf_init()\fP.
The client is allowed to use the \f(CWElf *\fP pointer
for its own purposes without restriction during the time the 
\f(CWDwarf_Debug\fP
is open, except that the client should not  \f(CWelf_end()\fP the
pointer till after  \f(CWdwarf_finish\fP is called.

.H 3 "dwarf_get_elf()"
.DS
\f(CWint dwarf_get_elf(
        Dwarf_Debug dbg,
        Elf **      elf,
        Dwarf_Error *error)\fP
.DE
When it returns \f(CWDW_DLV_OK\fP,
the function \f(CWdwarf_get_elf()\fP returns through the
pointer \f(CWelf\fP the \f(CWElf *\fP handle
used to access the object represented by the \f(CWDwarf_Debug\fP
descriptor \f(CWdbg\fP.  It returns \f(CWDW_DLV_ERROR\fP on error.

Because \f(CWint dwarf_init()\fP opens an Elf descriptor
on its fd and \f(CWdwarf_finish()\fP does not close that
descriptor, an app should use \f(CWdwarf_get_elf\fP
and should call \f(CWelf_end\fP with the pointer returned
through the \f(CWElf**\fP handle created by \f(CWint dwarf_init()\fP.

This function is not meaningful for a system that does not use the
Elf format for objects.

.H 3 "dwarf_finish()"
.DS
\f(CWint dwarf_finish(
        Dwarf_Debug dbg,
	Dwarf_Error *error)\fP
.DE
The function
\f(CWdwarf_finish()\fP releases all \fILibdwarf\fP internal resources 
associated with the descriptor \f(CWdbg\fP, and invalidates \f(CWdbg\fP.  
It returns \f(CWDW_DLV_ERROR\fP if there is an error during the
finishing operation.  It returns \f(CWDW_DLV_OK\fP 
for a successful operation.

Because \f(CWint dwarf_init()\fP opens an Elf descriptor
on its fd and \f(CWdwarf_finish()\fP does not close that
descriptor, an app should use \f(CWdwarf_get_elf\fP
and should call \f(CWelf_end\fP with the pointer returned
through the \f(CWElf**\fP handle created by \f(CWint dwarf_init()\fP.

.H 3 "dwarf_set_stringcheck()"
.DS
\f(CWint dwarf_set_stringcheck(
        int stringcheck)\fP
.DE
The function
\f(CWint dwarf_set_stringcheck()\fP sets a global flag
and returns the previous value of the global flag.

If the stringcheck global flag is zero (the default)
libdwarf does not do string length validity checks.
If the stringcheck global flag is non-zero 
libdwarf does do string length validity checks (the checks
do slow libdwarf down).

The global flag is really just 8 bits long, upperbits are not noticed
or recorded.

.H 3 "dwarf_set_reloc_application()"
.DS
\f(CWint dwarf_set_reloc_application(
        int apply)\fP
.DE
The function
\f(CWint dwarf_set_reloc_application()\fP sets a global flag
and returns the previous value of the global flag.

If the reloc_application global flag is non-zero (the default)
then the applicable .rela section (if one exists) will be
processed and applied to any DWARF section when it is read in.
If the reloc_application global flag is zero no such
relocation-application is attempted.

Not all 
machine types (elf header e_machine) 
or all relocations are supported, but then very few
relocation types apply to DWARF debug sections.

The global flag is really just 8 bits long, upperbits are not noticed
or recorded. 

It seems unlikely anyone will need to call this function.

.H 3 "dwarf_record_cmdline_options()"
.DS
\f(CWint dwarf_record_cmdline_options(
        Dwarf_Cmdline_Options options)\fP
.DE
The function
\f(CWint dwarf_record_cmdline_options()\fP 
copies a Dwarf_Cmdline_Options structure from
consumer code to libdwarf.

The structure is defined in \f(CWlibdwarf.h\fP. 

The initial version of this structure has a single field
\f(CWcheck_verbose_mode\fP which, if non-zero, tells
libdwarf to print some detailed messages to stdout in case
certain errors are detected.

The default for this value is FALSE (0) so the extra messages
are off by default.

.H 2 "Section size operations"
.P
These operations are informative but not normally needed.
.H 3 "dwarf_get_section_max_offsets_b()"
.DS
\f(CWint dwarf_get_section_max_offsets_b(Dwarf_debug dbg,
    Dwarf_Unsigned * /*debug_info_size*/,
    Dwarf_Unsigned * /*debug_abbrev_size*/,
    Dwarf_Unsigned * /*debug_line_size*/,
    Dwarf_Unsigned * /*debug_loc_size*/,
    Dwarf_Unsigned * /*debug_aranges_size*/,
    Dwarf_Unsigned * /*debug_macinfo_size*/,
    Dwarf_Unsigned * /*debug_pubnames_size*/,
    Dwarf_Unsigned * /*debug_str_size*/,
    Dwarf_Unsigned * /*debug_frame_size*/,
    Dwarf_Unsigned * /*debug_ranges_size*/,
    Dwarf_Unsigned * /*debug_pubtypes_size*/,
    Dwarf_Unsigned * /*debug_types_size*/);
.DE
.P
The function
\f(CWdwarf_get_section_max_offsets_b()\fP an open
Dwarf_Dbg and reports on the section sizes by pushing
section size values  back through the pointers.

Created in October 2011.

.H 3 "dwarf_get_section_max_offsets()"
.DS
\f(CWint dwarf_get_section_max_offsets(Dwarf_debug dbg,
    Dwarf_Unsigned * /*debug_info_size*/,
    Dwarf_Unsigned * /*debug_abbrev_size*/,
    Dwarf_Unsigned * /*debug_line_size*/,
    Dwarf_Unsigned * /*debug_loc_size*/,
    Dwarf_Unsigned * /*debug_aranges_size*/,
    Dwarf_Unsigned * /*debug_macinfo_size*/,
    Dwarf_Unsigned * /*debug_pubnames_size*/,
    Dwarf_Unsigned * /*debug_str_size*/,
    Dwarf_Unsigned * /*debug_frame_size*/,
    Dwarf_Unsigned * /*debug_ranges_size*/,
    Dwarf_Unsigned * /*debug_pubtypes_size*/);
.DE
.P
The function is the same as \f(CWdwarf_get_section_max_offsets_b()\fP
except it is missing the \f(CWdebug_types_size()\fP argument.
Though obsolete it is still supported.



.H 2 "Debugging Information Entry Delivery Operations"
These functions are concerned with accessing debugging information 
entries. 

.H 3 "dwarf_next_cu_header_c()"
.DS
\f(CWint dwarf_next_cu_header_c(
        Dwarf_debug dbg,
        Dwarf_Bool is_info,
        Dwarf_Unsigned *cu_header_length,
        Dwarf_Half     *version_stamp,
        Dwarf_Unsigned *abbrev_offset,
        Dwarf_Half     *address_size,
        Dwarf_Half     *offset_size,
        Dwarf_Half     *extension_size,
        Dwarf_Sig8     *signature,
        Dwarf_Unsigned *typeoffset
        Dwarf_Unsigned *next_cu_header,
        Dwarf_Error    *error);
.DE
The function
\f(CWdwarf_next_cu_header_c()\fP operates on
the either the .debug_info   section
(if \f(CWis_info\fP is non-zero) or .debug_types
section   
(if \f(CWis_info\fP is zero).
It returns \f(CWDW_DLV_ERROR\fP 
if it fails, and
\f(CWDW_DLV_OK\fP if it succeeds.
.P
If it succeeds, \f(CW*next_cu_header\fP is set to
the offset in the .debug_info section of the next 
compilation-unit header if it succeeds.  On reading the last 
compilation-unit header in the .debug_info section it contains 
the size of the .debug_info or debug_types section.
The next call to 
\f(CWdwarf_next_cu_header_b()\fP returns \f(CWDW_DLV_NO_ENTRY\fP
without reading a 
compilation-unit or setting \f(CW*next_cu_header\fP.  
Subsequent calls to \f(CWdwarf_next_cu_header()\fP 
repeat the cycle by reading the first compilation-unit and so on.  
.P
The other 
values returned through pointers are the values in the compilation-unit 
header.  If any of \f(CWcu_header_length\fP, \f(CWversion_stamp\fP,
\f(CWabbrev_offset\fP, \f(CWaddress_size\fP, 
\f(CWoffset_size\fP, \f(CWextension_size\fP,
\f(CWsignature\fP, or \f(CWtypeoffset\fP,
is \f(CWNULL\fP, the 
argument is ignored (meaning it is not an error to provide a 
\f(CWNULL\fP pointer for any or all of these arguments).
.P
\f(CWcu_header_length\fP returns the length in bytes of the compilation
unit header.
.P
\f(CWversion_stamp\fP returns the section version, which
would be (for .debug_info) 2 for DWARF2, 3 for DWARF4, or
4 for DWARF4.
.P
\f(CWabbrev_offset\fP returns the .debug_abbrev
section offset of the abbreviations
for this compilation unit.
.P
\f(CWaddress_size\fP returns the size of an address in this
compilation unit.  Which is usually 4 or 8.
.P
\f(CWoffset_size\fP returns the size in bytes of
an offset for the compilation unit.  The offset size
is 4 for 32bit dwarf
and 8 for 64bit dwarf.
This is the offset size in dwarf data, not
the address size inside the executable code.
The offset size can be 4 even
if embedded in a 64bit elf file (which
is normal for 64bit elf), and can be 8 even in
a 32bit elf file (which probably will never be seen 
in practice).
.P
The 
\f(CWextension_size\fP pointer is only relevant if
the \f(CWoffset_size\fP pointer returns 8.
The value is not normally useful but is returned
through the pointer for completeness.
The pointer \f(CWextension_size\fP returns 0 
if the CU is MIPS/IRIX non-standard 64bit dwarf
(MIPS/IRIX 64bit dwarf was created years before DWARF3
defined 64bit dwarf)
and returns 4 if the dwarf uses the standard 64bit
extension (the 4 is the size in bytes of the 0xffffffff
in the initial length field
which indicates the following 8 bytes in the .debug_info section
are the real length).
See the DWARF3 or DWARF4 standard, section 7.4.
.P
The
\f(CWsignature\fP pointer is only relevant if
\f(CWis_info\fP is zero, and if relevant the 8 byte type
signature of the .debug_types CU header is assigned through
the pointer.
.P
The
\f(CWtypeoffset\fP pointer is only relevant if
\f(CWis_info\fP is zero, and if relevant the local offset
within the CU of the the type offset the .debug_types entry
represents is assigned through the pointer.
The
\f(CWtypeoffset\fP matters because a
DW_AT_type referencing the type unit may reference an inner type,
such as a  C++ class in a C++ namespace, but the type itself
has the enclosing namespace in the .debug_type type_unit.

.H 3 "dwarf_next_cu_header_b()"
.DS
\f(CWint dwarf_next_cu_header_b(
        Dwarf_debug dbg,
        Dwarf_Unsigned *cu_header_length,
        Dwarf_Half     *version_stamp,
        Dwarf_Unsigned *abbrev_offset,
        Dwarf_Half     *address_size,
        Dwarf_Half     *offset_size,
        Dwarf_Half     *extension_size,
        Dwarf_Unsigned *next_cu_header,
        Dwarf_Error    *error);
.DE
.P
This is obsolete as of October 2011 though supported.
.P
The function
\f(CWdwarf_next_cu_header_b()\fP  operates on 
the .debug_info section.  It operates exactly like
\f(CWdwarf_next_cu_header_c()\fP but
is missing the
\f(CWsignature\fP, and \f(CWtypeoffset\fP
fields.
This is kept for compatibility.
All code using this should be changed to use
\f(CWdwarf_next_cu_header_c()\fP

.H 3 "dwarf_next_cu_header()"
.P
The following is the original form, missing the
\f(CWoffset_size\fP, \f(CWextension_size\fP,
\f(CWsignature\fP, and \f(CWtypeoffset\fP
fields in
\f(CWdwarf_next_cu_header_c()\fP. 
This is kept for compatibility.
All code using this should be changed to use
\f(CWdwarf_next_cu_header_c()\fP
.DS
\f(CWint dwarf_next_cu_header(
        Dwarf_debug dbg,
        Dwarf_Unsigned *cu_header_length,
        Dwarf_Half     *version_stamp,
        Dwarf_Unsigned *abbrev_offset,
        Dwarf_Half     *address_size,
        Dwarf_Unsigned *next_cu_header,
        Dwarf_Error    *error);
.DE

.H 3 "dwarf_siblingof_b()"
.DS
\f(CWint dwarf_siblingof_b(
        Dwarf_Debug dbg, 
        Dwarf_Die die, 
        Dwarf_Bool is_info,
	Dwarf_Die *return_sib,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_siblingof_b()\fP 
returns \f(CWDW_DLV_ERROR\fP and sets the \f(CWerror\fP pointer on error.
If there is no sibling it returns \f(CWDW_DLV_NO_ENTRY\fP.
When it succeeds,
\f(CWdwarf_siblingof_b()\fP returns
\f(CWDW_DLV_OK\fP  and sets \f(CW*return_sib\fP to the \f(CWDwarf_Die\fP 
descriptor of the sibling of \f(CWdie\fP.

If \f(CWis_info\fP is non-zero then the  \f(CWdie\fP
is assumed to refer to a .debug_info DIE.  
If \f(CWis_info\fP is zero then the  \f(CWdie\fP
is assumed to refer to a .debug_types DIE.  
Note that the first call (the call that gets the compilation-unit
DIE in a compilation unit) passes in a NULL \f(CWdie\fP
so having the caller pass in \f(CWis_info\fP is essential.
And if \f(CWdie\fP is non-NULL it is still essential for the
call to pass in  \f(CWis_info\fP set properly to reflect the
section the DIE came from.
The function
\f(CWdwarf_get_die_infotypes_flag()\fP  is of interest as
it returns the proper is_info value from any non-NULL \f(CWdie\fP
pointer.


If \f(CWdie\fP is \fINULL\fP, the \f(CWDwarf_Die\fP descriptor of the
first die in the compilation-unit is returned.  
This die has the
\f(CWDW_TAG_compile_unit\fP,
\f(CWDW_TAG_partial_unit\fP,
or \f(CWDW_TAG_type_unit\fP
tag.

.in +2
.DS
\f(CWDwarf_Die return_sib = 0;
Dwarf_Error error = 0;
int res;
Dwarf_Bool is_info = 1;
/* in_die might be NULL or a valid Dwarf_Die */
res = dwarf_siblingof_b(dbg,in_die,is_info,&return_sib, &error);
if (res == DW_DLV_OK) {
   /* Use return_sib here. */
   dwarf_dealloc(dbg, return_sib, DW_DLA_DIE);
   /* return_sib is no longer usable for anything, we
      ensure we do not use it accidentally with: */
   return_sib = 0;
}\fP
.DE
.in -2

.H 3 "dwarf_siblingof()"
.DS
\f(CWint dwarf_siblingof(
        Dwarf_Debug dbg,
        Dwarf_Die die,
        Dwarf_Die *return_sib,
        Dwarf_Error *error)\fP
.DE
.P
\f(CWint dwarf_siblingof()\fP operates exactly the same as
\f(CWint dwarf_siblingof_b()\fP, but 
\f(CWint dwarf_siblingof()\fP refers only to .debug_info
DIEs.


.H 3 "dwarf_child()"
.DS
\f(CWint dwarf_child(
        Dwarf_Die die, 
	Dwarf_Die *return_kid,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_child()\fP 
returns \f(CWDW_DLV_ERROR\fP and sets the \f(CWerror\fP die on error.
If there is no child it returns \f(CWDW_DLV_NO_ENTRY\fP.
When it succeeds,
\f(CWdwarf_child()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_kid\fP
to the \f(CWDwarf_Die\fP descriptor 
of the first child of \f(CWdie\fP.
The function 
\f(CWdwarf_siblingof()\fP can be used with the return value of 
\f(CWdwarf_child()\fP to access the other children of \f(CWdie\fP. 

.in +2
.DS
\f(CWDwarf_Die return_kid = 0;
Dwarf_Error error = 0;
int res;

res = dwarf_child(dbg,in_die,&return_kid, &error);
if (res == DW_DLV_OK) {
   /* Use return_kid here. */
   dwarf_dealloc(dbg, return_kid, DW_DLA_DIE);
   /* return_die is no longer usable for anything, we
      ensure we do not use it accidentally with: */
   return_kid = 0;
}\fP
.DE
.in -2

.H 3 "dwarf_offdie_b()"
.DS
\f(CWint dwarf_offdie_b(
        Dwarf_Debug dbg,
        Dwarf_Off offset, 
        Dwarf_Bool is_info,
	Dwarf_Die *return_die,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_offdie_b()\fP 
returns \f(CWDW_DLV_ERROR\fP and sets the \f(CWerror\fP die on error.
When it succeeds,
\f(CWdwarf_offdie_b()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_die\fP
to the
the \f(CWDwarf_Die\fP 
descriptor of the debugging information entry at \f(CWoffset\fP in 
the section containing debugging information entries i.e the .debug_info
section.  
A return of \f(CWDW_DLV_NO_ENTRY\fP
means that the \f(CWoffset\fP in the section is of a byte containing
all 0 bits, indicating that there
is no abbreviation code. Meaning this 'die offset' is not
the offset of a real die, but is instead an offset of a null die,
a padding die, or of some random zero byte: this should
not be returned in normal use.
.P
It is the user's 
responsibility to make sure that \f(CWoffset\fP is the start of a valid 
debugging information entry.  The result of passing it an invalid 
offset could be chaos.
.P
If \f(CWis_info\fP is non-zero the \f(CWoffset\fP must refer
to a .debug_info section offset. 
If \f(CWis_info\fP zero the \f(CWoffset\fP must refer
to a .debug_types section offset. 
Error returns or misleading
values may result if the 
\f(CWis_info\fP flag 
or the \f(CWoffset\fP value
are incorrect.

.in +2
.DS
\f(CWDwarf_Error error = 0;
Dwarf_Die return_die = 0;
int res;

res = dwarf_offdie_b(dbg,die_offset,&return_die, &error);
if (res == DW_DLV_OK) {
   /* Use return_die here. */
   dwarf_dealloc(dbg, return_die, DW_DLA_DIE);
   /* return_die is no longer usable for anything, we
      ensure we do not use it accidentally with: */
   return_die = 0;
}\fP
.DE
.in -2

.H 3 "dwarf_offdie()"
.DS
\f(CWint dwarf_offdie(
        Dwarf_Debug dbg,
        Dwarf_Off offset, 
	Dwarf_Die *return_die,
        Dwarf_Error *error)\fP
.DE
.P
The function \f(CWdwarf_offdie()\fP is obsolete, use
\f(CWdwarf_offdie_b()\fP instead.
The function is still supported in the library, but only
references the .debug_info section.


.H 3 "dwarf_validate_die_sibling()"
.DS
\f(CWint validate_die_sibling(
        Dwarf_Die sibling,
        Dwarf_Off *offset)\fP
.DE
When used correctly in a depth-first walk of a DIE tree this
function validates that any DW_AT_sibling attribute gives
the same offset as the direct tree walk.
That is the only purpose of this function.

The function \f(CWdwarf_validate_die_sibling()\fP
returns \f(CWDW_DLV_OK\fP  if the last die processed
in a depth-first DIE tree walk was the same offset as
generated by a call to \f(CWdwarf_siblingof()\fP.
Meaning that the DW_AT_sibling attribute value, if any, was correct.

If the conditions are not met then DW_DLV_ERROR is returned
and  \f(CW*offset\fP is set to the offset
in the .debug_info section of the last DIE processed.
If the application prints the offset a knowledgeable
user may be able to figure out what the compiler did wrong.

.H 2 "Debugging Information Entry Query Operations"
These queries return specific information about debugging information 
entries or a descriptor that can be used on subsequent queries when 
given a \f(CWDwarf_Die\fP descriptor.  Note that some operations are 
specific to debugging information entries that are represented by a 
\f(CWDwarf_Die\fP descriptor of a specific type. 
For example, not all 
debugging information entries contain an attribute having a name, so 
consequently, a call to \f(CWdwarf_diename()\fP using a \f(CWDwarf_Die\fP 
descriptor that does not have a name attribute will return
\f(CWDW_DLV_NO_ENTRY\fP.
This is not an error, i.e. calling a function that needs a specific
attribute is not an error for a die that does not contain that specific
attribute.
.P
There are several methods that can be used to obtain the value of an
attribute in a given die:
.AL 1
.LI
Call \f(CWdwarf_hasattr()\fP to determine if the debugging information
entry has the attribute of interest prior to issuing the query for
information about the attribute.

.LI
Supply an \f(CWerror\fP argument, and check its value after the call to 
a query indicates an unsuccessful return, to determine the nature of the 
problem.  The \f(CWerror\fP argument will indicate whether an error occurred, 
or the specific attribute needed was missing in that die.

.LI
Arrange to have an error handling function invoked upon detection of an 
error (see \f(CWdwarf_init()\fP).

.LI
Call \f(CWdwarf_attrlist()\fP and iterate through the returned list of
attributes, dealing with each one as appropriate.
.LE
.P

.H 3 "dwarf_get_die_infotypes_flag()"
.DS
\f(CWDwarf_Bool dwarf_get_die_infotypes_flag(Dwarf_Die die)\fP
.DE
.P
The function \f(CWdwarf_tag()\fP returns the section flag
indicating which section the DIE originates from.
If the returned value is non-zero the DIE 
originates from the .debug_info section.
If the returned value is zero the DIE 
originates from the .debug_types section.

.H 3 "dwarf_tag()"
.DS
\f(CWint dwarf_tag(
        Dwarf_Die die, 
	Dwarf_Half *tagval,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_tag()\fP returns the \f(CWtag\fP of \f(CWdie\fP
through the pointer  \f(CWtagval\fP if it succeeds. 
It returns \f(CWDW_DLV_OK\fP if it succeeds.
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 3 "dwarf_dieoffset()"
.DS
\f(CWint dwarf_dieoffset(
        Dwarf_Die die, 
	Dwarf_Off * return_offset,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
the function \f(CWdwarf_dieoffset()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP
to the position of \f(CWdie\fP 
in the section containing debugging information entries
(the \f(CWreturn_offset\fP is a section-relative offset).  
In other words,
it sets \f(CWreturn_offset\fP 
to the offset of the start of the debugging information entry
described by \f(CWdie\fP in the section containing dies i.e .debug_info.  
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 3 "dwarf_die_CU_offset()"
.DS
\f(CWint dwarf_die_CU_offset(
        Dwarf_Die die,
  	Dwarf_Off *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_die_CU_offset()\fP is similar to 
\f(CWdwarf_dieoffset()\fP, except that it puts the offset of the DIE 
represented by the \f(CWDwarf_Die\fP \f(CWdie\fP, from the 
start of the compilation-unit that it belongs to rather than the start 
of .debug_info (the \f(CWreturn_offset\fP is a CU-relative offset).  

.H 3 "dwarf_die_offsets()"
.DS
\f(CWint dwarf_die_offsets(
        Dwarf_Die die,
        Dwarf_Off *global_off,
        Dwarf_Off *cu_off,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_die_offsets()\fP is a combination of
\f(CWdwarf_dieoffset()\fP and \f(CWdwarf_die_cu_offset()\fP
in that it returns both the global .debug_info offset and
the CU-relative offset of the \f(CWdie\fP in a single call.


.H 3 "dwarf_ptr_CU_offset()"
.DS
\f(CWint dwarf_ptr_CU_offset(
        Dwarf_CU_Context cu_context,
  	Dwarf_Byte_ptr di_ptr ,
        Dwarf_Off *cu_off)\fP
.DE
Given a valid CU context pointer and a pointer into that CU
context,
the function \f(CWdwarf_ptr_CU_offset()\fP returns DW_DLV_OK
and sets \f(CW*cu_off\fP to the CU-relative (local) offset
in that CU. 


.H 3 "dwarf_CU_dieoffset_given_die()"
.DS
\f(CWint dwarf_CU_dieoffset_given_die(
        Dwarf_Die given_die,
  	Dwarf_Off *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_CU_dieoffset_given_die()\fP is similar to 
\f(CWdwarf_die_CU_offset()\fP, except that it puts the 
global offset of the CU DIE owning \f(CWgiven_die\fP 
of .debug_info (the \f(CWreturn_offset\fP is a global section offset).  
.P
This is useful when processing a DIE tree and encountering
an error or other surprise in a DIE, as the \f(CWreturn_offset\fP
can be passed to \f(CWdwarf_offdie_b()\fP to return a pointer
to the CU die of the CU owning the \f(CWgiven_die\fP passed
to \f(CWdwarf_CU_dieoffset_given_die()\fP. The consumer can
extract information from the CU die and the \f(CWgiven_die\fP  
(in the normal way) and print it.

An example  (a snippet) of code using this function
follows. It assumes that \f(CWin_die\fP is a DIE
that, for some reason, you have decided needs CU context
printed (assuming \f(CWprint_die_data\fP 
does some reasonable printing).

.in +2
.DS
int res;
Dwarf_Off cudieoff = 0;
Dwarf_Die cudie = 0;

print_die_data(dbg,in_die);
res = dwarf_CU_dieoffset_given_die(in_die,&cudieoff,&error);
if(res != DW_DLV_OK) {
    printf("FAIL: dwarf_CU_dieoffset_given_die did not work\n");
    exit(1);
}
res = dwarf_offdie_b(dbg,cudieoff,&cudie,&error);
if(res != DW_DLV_OK) {
    printf("FAIL: dwarf_offdie did not work\n");
    exit(1);
}
print_die_data(dbg,cudie);
dwarf_dealloc(dbg,cudie, DW_DLA_DIE);
.DE
.in -2



.H 3 "dwarf_die_CU_offset_range()"
.DS
\f(CWint dwarf_die_CU_offset_range(
        Dwarf_Die die,
        Dwarf_Off *cu_global_offset,
        Dwarf_Off *cu_length,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_die_CU_offset_range()\fP 
returns the offset of the beginning of the CU and the length of the CU.
The offset and length are of the entire CU that this DIE is
a part of.  It is used by dwarfdump (for example) to check
the validity of offsets.
Most applications will have no reason to call this function.


.H 3 "dwarf_diename()"
.DS
\f(CWint dwarf_diename(
        Dwarf_Die die, 
	char  ** return_name,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
the function \f(CWdwarf_diename()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP
to
a pointer to a
null-terminated string of characters that represents the name
attribute of \f(CWdie\fP.
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not have a name attribute.
It returns \f(CWDW_DLV_ERROR\fP if
an error occurred.  
The storage pointed to by a successful return of 
\f(CWdwarf_diename()\fP should be freed using the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest (see 
\f(CWdwarf_dealloc()\fP).

.H 3 "dwarf_die_abbrev_code()"
.DS
\f(CWint dwarf_die_abbrev_code( Dwarf_Die die)\fP
.DE
The function returns
the abbreviation code of the DIE.
That is, it returns the abbreviation "index"
into the abbreviation table for the compilation unit
of which the DIE is a part.
It cannot fail. No errors are possible.
The pointer \f(CWdie()\fP must not be NULL.

.H 3 "dwarf_die_abbrev_children_flag()"
.DS
\f(CWint dwarf_die_abbrev_children_flag( Dwarf_Die die,
      Dwarf_Half *has_child)\fP
.DE
The function returns the has-children flag of the \f(CWdie\fP
passed in through the \f(CW*has_child\fP passed in and returns
\f(CWDW_DLV_OK\fP on success.
A non-zero value of \f(CW*has_child\fP means the \f(CWdie\fP
has children.

On failure it returns \f(CWDW_DLV_ERROR\fP.

The function was developed to let
consumer code do better error reporting
in some circumstances, it is not generally needed.


.H 3 "dwarf_get_version_of_die()"
.DS
\f(CWint dwarf_get_version_of_die(Dwarf_Die die,
    Dwarf_Half *version,
    Dwarf_Half *offset_size)\fP
.DE
The function returns the CU context version through \f(CW*version\fP
and the CU context offset-size through \f(CW*offset_size\fP and
returns \f(CWDW_DLV_OK\fP on success.

In case of error, the only errors possible involve
an inappropriate NULL \f(CWdie\fP pointer so no Dwarf_Debug
pointer is available.  Therefore setting a Dwarf_Error would not
be very meaningful (there is no Dwarf_Debug to
attach it to).  The function returns DW_DLV_ERROR on error.

The values returned through the pointers are the values
two arguments to  dwarf_get_form_class() requires.

.H 3 "dwarf_attrlist()"
.DS
\f(CWint dwarf_attrlist(
        Dwarf_Die die, 
        Dwarf_Attribute** attrbuf, 
	Dwarf_Signed *attrcount,
        Dwarf_Error *error)\fP
.DE
When it returns \f(CWDW_DLV_OK\fP,
the function \f(CWdwarf_attrlist()\fP sets \f(CWattrbuf\fP to point 
to an array of \f(CWDwarf_Attribute\fP descriptors corresponding to
each of the attributes in die, and returns the number of elements in 
the array through \f(CWattrcount\fP.  
\f(CWDW_DLV_NO_ENTRY\fP is returned if the count is zero (no 
\f(CWattrbuf\fP is allocated in this case).
\f(CWDW_DLV_ERROR\fP is returned on error.
On a successful return from \f(CWdwarf_attrlist()\fP, each of the
\f(CWDwarf_Attribute\fP descriptors should be individually freed using 
\f(CWdwarf_dealloc()\fP with the allocation type \f(CWDW_DLA_ATTR\fP, 
followed by free-ing the list pointed to by \f(CW*attrbuf\fP using
\f(CWdwarf_dealloc()\fP with the allocation type \f(CWDW_DLA_LIST\fP, 
when no longer of interest (see \f(CWdwarf_dealloc()\fP).

Freeing the attrlist:
.in +2
.DS
\f(CWDwarf_Unsigned atcnt;
Dwarf_Attribute *atlist;
int errv;

errv = dwarf_attrlist(somedie, &atlist,&atcnt, &error);
if (errv == DW_DLV_OK) {

        for (i = 0; i < atcnt; ++i) {
                /* use atlist[i] */
                dwarf_dealloc(dbg, atlist[i], DW_DLA_ATTR);
        }
        dwarf_dealloc(dbg, atlist, DW_DLA_LIST);
}\fP
.DE
.in -2
.P
.H 3 "dwarf_hasattr()"
.DS
\f(CWint dwarf_hasattr(
        Dwarf_Die die, 
        Dwarf_Half attr, 
	Dwarf_Bool *return_bool,
        Dwarf_Error *error)\fP
.DE
When it succeeds, the
function \f(CWdwarf_hasattr()\fP returns \f(CWDW_DLV_OK\fP
and sets \f(CW*return_bool\fP to \fInon-zero\fP if 
\f(CWdie\fP has the attribute \f(CWattr\fP and \fIzero\fP otherwise.
If it fails, it returns \f(CWDW_DLV_ERROR\fP.

.H 3 "dwarf_attr()"
.DS
\f(CWint dwarf_attr(
        Dwarf_Die die, 
        Dwarf_Half attr, 
	Dwarf_Attribute *return_attr,
        Dwarf_Error *error)\fP
.DE
.P
When it returns \f(CWDW_DLV_OK\fP,
the function \f(CWdwarf_attr()\fP
sets 
\f(CW*return_attr\fP to the  \f(CWDwarf_Attribute\fP 
descriptor of \f(CWdie\fP having the attribute \f(CWattr\fP.
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWattr\fP is not contained 
in \f(CWdie\fP. 
It returns \f(CWDW_DLV_ERROR\fP if an error occurred.


.H 3 "dwarf_lowpc()"
.DS
\f(CWint dwarf_lowpc(
        Dwarf_Die     die, 
	Dwarf_Addr  * return_lowpc,
        Dwarf_Error * error)\fP
.DE
The function \f(CWdwarf_lowpc()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_lowpc\fP
to the low program counter 
value associated with the \f(CWdie\fP descriptor if \f(CWdie\fP 
represents a debugging information entry with this attribute.  
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not have this 
attribute. 
It returns \f(CWDW_DLV_ERROR\fP if an error occurred. 

.H 3 "dwarf_highpc()"
.DS
\f(CWint dwarf_highpc(
        Dwarf_Die die, 
	Dwarf_Addr  * return_highpc,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_highpc()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_highpc\fP
the high program counter 
value associated with the \f(CWdie\fP descriptor if \f(CWdie\fP 
represents a debugging information entry with this attribute.  
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not have this 
attribute. 
It returns \f(CWDW_DLV_ERROR\fP if an error occurred. 

.H 3 "dwarf_bytesize()"
.DS
\f(CWDwarf_Signed dwarf_bytesize(
        Dwarf_Die        die, 
	Dwarf_Unsigned  *return_size,
        Dwarf_Error     *error)\fP
.DE
When it succeeds,
\f(CWdwarf_bytesize()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_size\fP
to the number of bytes 
needed to contain an instance of the aggregate debugging information 
entry represented by \f(CWdie\fP.  
It returns \f(CWDW_DLV_NO_ENTRY\fP if 
\f(CWdie\fP does not contain the byte size attribute \f(CWDW_AT_byte_size\fP.
It returns \f(CWDW_DLV_ERROR\fP if 
an error occurred.

.\"#if 0
.\".DS
.\"\f(CWDwarf_Bool dwarf_isbitfield(
.\"        Dwarf_Die die, 
.\"        Dwarf_Error *error)\fP
.\".DE
.\"The function \f(CWdwarf_isbitfield()\fP returns \fInon-zero\fP if 
.\"\f(CWdie\fP is a descriptor for a debugging information entry that 
.\"represents a bit field member.  It returns \fIzero\fP if \f(CWdie\fP 
.\"is not associated with a bit field member.  This function is currently
.\"unimplemented.
.\"#endif

.H 3 "dwarf_bitsize()"
.DS
\f(CWint dwarf_bitsize(
        Dwarf_Die die, 
	Dwarf_Unsigned  *return_size,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_bitsize()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_size\fP
to the number of 
bits 
occupied by the bit field value that is an attribute of the given
die.  
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not 
contain the bit size attribute \f(CWDW_AT_bit_size\fP.
It returns \f(CWDW_DLV_ERROR\fP if 
an error occurred.

.H 3 "dwarf_bitoffset()"
.DS
\f(CWint dwarf_bitoffset(
        Dwarf_Die die, 
	Dwarf_Unsigned  *return_size,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_bitoffset()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_size\fP
to the number of bits 
to the left of the most significant bit of the bit field value. 
This bit offset is not necessarily the net bit offset within the
structure or class , since \f(CWDW_AT_data_member_location\fP
may give a byte offset to this \f(CWDIE\fP and the bit offset
returned through the pointer
does not include the bits in the byte offset.
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not contain the 
bit offset attribute \f(CWDW_AT_bit_offset\fP.
It returns \f(CWDW_DLV_ERROR\fP if 
an error occurred.

.H 3 "dwarf_srclang()"
.DS
\f(CWint dwarf_srclang(
        Dwarf_Die die, 
	Dwarf_Unsigned  *return_lang,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_srclang()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_lang\fP
to
a code indicating the 
source language of the compilation unit represented by the descriptor 
\f(CWdie\fP.  
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not 
represent a source file debugging information entry (i.e. contain the 
attribute \f(CWDW_AT_language\fP).
It returns \f(CWDW_DLV_ERROR\fP if 
an error occurred.

.H 3 "dwarf_arrayorder()"
.DS
\f(CWint dwarf_arrayorder(
        Dwarf_Die die, 
	Dwarf_Unsigned  *return_order,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_arrayorder()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_order\fP
a code indicating 
the ordering of the array represented by the descriptor \f(CWdie\fP.
It returns \f(CWDW_DLV_NO_ENTRY\fP if \f(CWdie\fP does not contain the
array order attribute \f(CWDW_AT_ordering\fP.
It returns \f(CWDW_DLV_ERROR\fP if 
an error occurred.

.H 2 "Attribute Queries"
Based on the attributes form, these operations are concerned with 
returning uninterpreted attribute data.  Since it is not always 
obvious from the return value of these functions if an error occurred, 
one should always supply an \f(CWerror\fP parameter or have arranged 
to have an error handling function invoked (see \f(CWdwarf_init()\fP)
to determine the validity of the returned value and the nature of any 
errors that may have occurred.

A \f(CWDwarf_Attribute\fP descriptor describes an attribute of a
specific die.  Thus, each \f(CWDwarf_Attribute\fP descriptor is
implicitly associated with a specific die.

.H 3 "dwarf_hasform()"
.DS
\f(CWint dwarf_hasform(
        Dwarf_Attribute attr, 
        Dwarf_Half form, 
        Dwarf_Bool  *return_hasform,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_hasform()\fP returns 
\f(CWDW_DLV_OK\fP and  and puts a 
\fInon-zero\fP
 value in the 
\f(CW*return_hasform\fP boolean if the 
attribute represented by the \f(CWDwarf_Attribute\fP descriptor 
\f(CWattr\fP has the attribute form \f(CWform\fP.  
If the attribute does not have that form \fIzero\fP
is put into \f(CW*return_hasform\fP. 
\f(CWDW_DLV_ERROR\fP is returned on error.

.H 3 "dwarf_whatform()"
.DS
\f(CWint dwarf_whatform(
        Dwarf_Attribute attr,
        Dwarf_Half     *return_form,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_whatform()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_form\fP
to the attribute form code of 
the attribute represented by the \f(CWDwarf_Attribute\fP descriptor 
\f(CWattr\fP.  
It returns  \f(CWDW_DLV_ERROR\fP  on error.
An attribute using DW_FORM_indirect effectively has two forms.
This function returns the 'final' form for \f(CWDW_FORM_indirect\fP,
not the \f(CWDW_FORM_indirect\fP itself. This function is
what most applications will want to call.

.H 3 "dwarf_whatform_direct()"
.DS
\f(CWint dwarf_whatform_direct(
        Dwarf_Attribute attr,
        Dwarf_Half     *return_form,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_whatform_direct()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_form\fP
to the attribute form code of 
the attribute represented by the \f(CWDwarf_Attribute\fP descriptor 
\f(CWattr\fP.  
It returns  \f(CWDW_DLV_ERROR\fP  on error.
An attribute using \f(CWDW_FORM_indirect\fP effectively has two forms.
This returns the form 'directly' in the initial form field.
So when the form field is \f(CWDW_FORM_indirect\fP
this call returns the \f(CWDW_FORM_indirect\fP form, 
which is sometimes useful for dump utilities.

.H 3 "dwarf_whatattr()"
.DS
\f(CWint dwarf_whatattr(
        Dwarf_Attribute attr,
        Dwarf_Half     *return_attr,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_whatattr()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_attr\fP
to the attribute code 
represented by the \f(CWDwarf_Attribute\fP descriptor \f(CWattr\fP.  
It returns  \f(CWDW_DLV_ERROR\fP  on error.

.H 3 "dwarf_formref()"
.DS
\f(CWint dwarf_formref(
        Dwarf_Attribute attr, 
	Dwarf_Off     *return_offset,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_formref()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP
to the CU-relative offset
represented by the descriptor \f(CWattr\fP if the form of the attribute 
belongs to the \f(CWREFERENCE\fP class.
\f(CWattr\fP must be a CU-local reference, 
not form \f(CWDW_FORM_ref_addr\fP and not \f(CWDW_FORM_sec_offset\fP .  
It is an error for the form to
not belong to the \f(CWREFERENCE\fP class.
It returns \f(CWDW_DLV_ERROR\fP on error.

Beginning November 2010:
All \f(CWDW_DLV_ERROR\fP returns set \f(CW*return_offset\fP. Most
errors set \f(CW*return_offset\fP to zero, but
for error \f(CWDW_DLE_ATTR_FORM_OFFSET_BAD\fP 
the function sets \f(CW*return_offset\fP to the invalid
offset (which allows the caller to print a more
detailed error message).

See also \f(CWdwarf_global_formref\fP below.


.H 3 "dwarf_global_formref()"
.DS
\f(CWint dwarf_global_formref(
        Dwarf_Attribute attr, 
	Dwarf_Off     *return_offset,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_global_formref()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP
to the section-relative offset
represented by the descriptor \f(CWattr\fP if the form of the attribute 
belongs to the \f(CWREFERENCE\fP or other section-references classes. 
.P
\f(CWattr\fP can be any legal 
\f(CWREFERENCE\fP class form plus \f(CWDW_FORM_ref_addr\fP or
\f(CWDW_FORM_sec_offset\fP.
It is an error for the form to
not belong to one of the reference classes.
It returns \f(CWDW_DLV_ERROR\fP on error.
See also \f(CWdwarf_formref\fP above.
.P
The caller must determine which section the offset returned applies to.
The function \f(CWdwarf_get_form_class()\fP  is useful to determine
the applicable section.
.P
The function converts CU relative offsets from forms 
such as DW_FORM_ref4 into
global section offsets.

.H 3 "dwarf_convert_to_global_offset()"
.DS
\f(CWint dwarf_convert_to_global_offset(
        Dwarf_Attribute attr,
        Dwarf_Off     offset,
        Dwarf_Off     *return_offset,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_convert_to_global_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP
to the section-relative offset
represented by the cu-relative offset \f(CWoffset\fP 
if the form of the attribute
belongs to the \f(CWREFERENCE\fP class.
\f(CWattr\fP must be a CU-local reference (DWARF class REFERENCE) 
or form \f(CWDW_FORM_ref_addr\fP and the \f(CWattr\fP
must be directly relevant for the calculated \f(CW*return_offset\fP
to mean anything.

The function returns \f(CWDW_DLV_ERROR\fP on error.

The function is not strictly necessary but may be a 
convenience for attribute printing  in case of error.


.H 3 "dwarf_formaddr()"
.DS
\f(CWint dwarf_formaddr(
        Dwarf_Attribute attr, 
        Dwarf_Addr    * return_addr,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_formaddr()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_addr\fP
to
the address 
represented by the descriptor \f(CWattr\fP if the form of the attribute
belongs to the \f(CWADDRESS\fP class.  
It is an error for the form to
not belong to this class.  
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 3 "dwarf_formflag()"
.DS
\f(CWint dwarf_formflag(
	Dwarf_Attribute attr,
	Dwarf_Bool * return_bool,
	Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_formflag()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_bool\fP
\f(CW1\fP (i.e. true) (if the attribute has a non-zero value)
or \f(CW0\fP (i.e. false) (if the attribute has a zero value).
It returns \f(CWDW_DLV_ERROR\fP on error or if the \f(CWattr\fP
does not have form flag.

.H 3 "dwarf_formudata()"
.DS
\f(CWint dwarf_formudata(
        Dwarf_Attribute   attr, 
	Dwarf_Unsigned  * return_uvalue,
        Dwarf_Error     * error)\fP
.DE
The function
\f(CWdwarf_formudata()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_uvalue\fP
to
the \f(CWDwarf_Unsigned\fP 
value of the attribute represented by the descriptor \f(CWattr\fP if the
form of the attribute belongs to the \f(CWCONSTANT\fP class.  
It is an 
error for the form to not belong to this class.  
It returns \f(CWDW_DLV_ERROR\fP on error.

Never returns \f(CWDW_DLV_NO_ENTRY\fP.

For DWARF2 and DWARF3, \f(CWDW_FORM_data4\fP and \f(CWDW_FORM_data8\fP
are possibly class \f(CWCONSTANT\fP, 
and for DWARF4 and later they
are definitely class \f(CWCONSTANT\fP.

.H 3 "dwarf_formsdata()"
.DS
\f(CWint dwarf_formsdata(
        Dwarf_Attribute attr, 
	Dwarf_Signed  * return_svalue,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_formsdata()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_svalue\fP
to
the \f(CWDwarf_Signed\fP 
value of the attribute represented by the descriptor \f(CWattr\fP if the
form of the attribute belongs to the \f(CWCONSTANT\fP class.  
It is an 
error for the form to not belong to this class.  
If the size of the data 
attribute referenced is smaller than the size of the \f(CWDwarf_Signed\fP
type, its value is sign extended.  
It returns \f(CWDW_DLV_ERROR\fP on error.

Never returns \f(CWDW_DLV_NO_ENTRY\fP.

For DWARF2 and DWARF3, \f(CWDW_FORM_data4\fP and \f(CWDW_FORM_data8\fP
are possibly class \f(CWCONSTANT\fP, 
and for DWARF4 and later they
are definitely class \f(CWCONSTANT\fP.

.H 3 "dwarf_formblock()"
.DS
\f(CWint dwarf_formblock(
        Dwarf_Attribute attr, 
	Dwarf_Block  ** return_block,
        Dwarf_Error *   error)\fP
.DE
The function \f(CWdwarf_formblock()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_block\fP
to
a pointer to a 
\f(CWDwarf_Block\fP structure containing the value of the attribute 
represented by the descriptor \f(CWattr\fP if the form of the 
attribute belongs to the \f(CWBLOCK\fP class.  
It is an error
for the form to not belong to this class.  
The storage pointed 
to by a successful return of \f(CWdwarf_formblock()\fP should 
be freed using the allocation type \f(CWDW_DLA_BLOCK\fP,  when 
no longer of interest (see \f(CWdwarf_dealloc()\fP).  
It returns
\f(CWDW_DLV_ERROR\fP on error.


.H 3 "dwarf_formstring()"

.DS
\f(CWint dwarf_formstring(
        Dwarf_Attribute attr, 
	char        **  return_string,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_formstring()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_string\fP
to
a pointer to a 
null-terminated string containing  the value of the attribute 
represented by the descriptor \f(CWattr\fP if the form of the
attribute belongs to the \f(CWSTRING\fP class.  
It is an error
for the form to not belong to this class.  
The storage pointed 
to by a successful return of \f(CWdwarf_formstring()\fP 
should not be freed.  The pointer points into
existing DWARF memory and the pointer becomes stale/invalid
after a call to \f(CWdwarf_finish\fP.
\f(CWdwarf_formstring()\fP returns \f(CWDW_DLV_ERROR\fP on error.

.H 3 "dwarf_formsig8()"
.DS
\f(CWint dwarf_formsig8(
        Dwarf_Attribute attr,
        Dwarf_Sig8  * return_sig8,
        Dwarf_Error *   error)\fP
.DE
The function \f(CWdwarf_formsig8()\fP returns
\f(CWDW_DLV_OK\fP and copies the 8 byte signature
to a \f(CWDwarf_Sig8\fP structure provided by the caller
if the form of the
attribute is of form \f(CWDW_FORM_ref_sig8\fP
( a member of the \f(CWREFERENCE\fP class).  
It is an error
for the form to be anything but \f(CWDW_FORM_ref_sig8\fP. 
It returns \f(CWDW_DLV_ERROR\fP on error.
.P
This form is used to refer to a type unit.

.H 3 "dwarf_formsig8()"
.DS
\f(CWint dwarf_formexprloc(
        Dwarf_Attribute attr,
        Dwarf_Unsigned * return_exprlen,
        Dwarf_Ptr  * block_ptr,
        Dwarf_Error *   error)\fP
.DE
The function \f(CWdwarf_formexprloc()\fP returns
\f(CWDW_DLV_OK\fP and sets the two values thru the pointers
to the length and bytes of the DW_FORM_exprloc entry
if the form of the
attribute is of form \f(CWDW_FORM_experloc\fP.
It is an error
for the form to be anything but \f(CWDW_FORM_exprloc\fP. 
It returns \f(CWDW_DLV_ERROR\fP on error.
.P
On success the value set through the
\f(CWreturn_exprlen\fP pointer is the length
of the location expression.
On success the value set through the
\f(CWblock_ptr\fP pointer is a pointer to 
the bytes of the location expression itself.

.H 3 "dwarf_get_form_class()"
.DS
\f(CWenum Dwarf_Form_Class dwarf_get_form_class(
    Dwarf_Half dwversion,
    Dwarf_Half attrnum,
    Dwarf_Half offset_size,
    Dwarf_Half form)\fP
.DE
.P
The function is just for the convenience
of libdwarf clients that might wish to categorize
the FORM of a particular attribute.
The DWARF specification divides FORMs into classes
in Chapter 7 and this function figures out the correct
class for a form. 
.P
The \f(CWdwversion\fP passed in shall be the dwarf version
of the compilation unit involved (2 for DWARF2, 3 for
DWARF3, 4 for DWARF 4).
The \f(CWattrnum\fP passed in shall be the attribute
number of the attribute involved (for example, \f(CWDW_AT_name\fP ).
The \f(CWoffset_size\fP passed in shall be the 
length of an offset in the current compilation unit 
(4 for 32bit dwarf or 8 for 64bit dwarf).
The \f(CWform\fP passed in shall be the attribute form number.
If \f(CWform\fP \f(CWDW_FORM_indirect\fP
is passed in \f(CWDW_FORM_CLASS_UNKNOWN\fP will be returned
as this form has no defined 'class'.
.P
When it returns \f(CWDW_FORM_CLASS_UNKNOWN\fP the
function is simply saying it could not determine the
correct class given the arguments
presented.  Some user-defined
attributes might have this problem.

The function \f(CWdwarf_get_version_of_die()\fP may be helpful
in filling out arguments for a call to \f(CWdwarf_get_form_class()\fP.

.H 3 "dwarf_loclist_n()"
.DS
\f(CWint dwarf_loclist_n(
        Dwarf_Attribute attr, 
        Dwarf_Locdesc ***llbuf,
        Dwarf_Signed  *listlen,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_loclist_n()\fP sets \f(CW*llbuf\fP to point to 
an array of \f(CWDwarf_Locdesc\fP pointers corresponding to each of
the location expressions in a location list, and sets
\f(CW*listlen\fP to the number 
of elements in the array and 
returns \f(CWDW_DLV_OK\fP if the attribute is
appropriate.
.P
This is the preferred function for Dwarf_Locdesc as
it is the interface allowing access to an entire
loclist. (use of \f(CWdwarf_loclist_n()\fP is
suggested as the better interface, though 
\f(CWdwarf_loclist()\fP is still
supported.)
.P
If the attribute is a reference to a location list
(DW_FORM_data4 or DW_FORM_data8)
the location list entries are used to fill
in all the fields of the \f(CWDwarf_Locdesc\fP(s) returned.
.P
If the attribute is a location description
(DW_FORM_block2 or DW_FORM_block4)
then some of the \f(CWDwarf_Locdesc\fP values of the single
\f(CWDwarf_Locdesc\fP record are set to 'sensible'
but arbitrary values.  Specifically, ld_lopc is set to 0 and
ld_hipc is set to all-bits-on. And \f(CW*listlen\fP is set to 1.
.P
It returns \f(CWDW_DLV_ERROR\fP on error. 
.P
\f(CWdwarf_loclist_n()\fP works on \f(CWDW_AT_location\fP, 
\f(CWDW_AT_data_member_location\fP, \f(CWDW_AT_vtable_elem_location\fP,
\f(CWDW_AT_string_length\fP, \f(CWDW_AT_use_location\fP, and 
\f(CWDW_AT_return_addr\fP attributes.  
.P
If the attribute is \f(CWDW_AT_data_member_location\fP the value
may be of class CONSTANT.  \f(CWdwarf_loclist_n()\fP is unable
to read class CONSTANT, so you need to first determine the
class using \f(CWdwarf_get_form_class()\fP and if it is
class CONSTANT call
\f(CWdwarf_formsdata()\fP or \f(CWdwarf_formudata()\fP
to get the constant value (you may need to call both as
DWARF4 does not define the signedness of the constant value).
.P
Storage allocated by a successful call of \f(CWdwarf_loclist_n()\fP should 
be deallocated when no longer of interest (see \f(CWdwarf_dealloc()\fP).
The block of \f(CWDwarf_Loc\fP structs pointed to by the \f(CWld_s\fP 
field of each \f(CWDwarf_Locdesc\fP structure 
should be deallocated with the allocation type 
\f(CWDW_DLA_LOC_BLOCK\fP. 
and  the \f(CWllbuf[]\fP space pointed to should be deallocated with
allocation type \f(CWDW_DLA_LOCDESC\fP.
This should be followed by deallocation of the \f(CWllbuf\fP
using the allocation type \f(CWDW_DLA_LIST\fP.
.in +2
.DS
\f(CWDwarf_Signed lcnt;
Dwarf_Locdesc **llbuf;
int lres;

lres = dwarf_loclist_n(someattr, &llbuf,&lcnt &error);
if (lres == DW_DLV_OK) {
        for (i = 0; i < lcnt; ++i) {
            /* use llbuf[i] */

            dwarf_dealloc(dbg, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK);
	    dwarf_dealloc(dbg,llbuf[i], DW_DLA_LOCDESC);
        }
        dwarf_dealloc(dbg, llbuf, DW_DLA_LIST);
}\fP
.DE
.in -2
.P

.H 3 "dwarf_loclist()"
.DS
\f(CWint dwarf_loclist(
        Dwarf_Attribute attr, 
        Dwarf_Locdesc **llbuf,
        Dwarf_Signed  *listlen,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_loclist()\fP sets \f(CW*llbuf\fP to point to 
a \f(CWDwarf_Locdesc\fP pointer for the single location expression
it can return.
It sets
\f(CW*listlen\fP to 1.
and returns \f(CWDW_DLV_OK\fP 
if the attribute is
appropriate.
.P
It is less flexible than \f(CWdwarf_loclist_n()\fP in that
\f(CWdwarf_loclist()\fP can handle a maximum of one
location expression, not a full location list.
If a location-list is present it returns only
the first location-list entry location description.
Use \f(CWdwarf_loclist_n()\fP instead.
.P
It returns \f(CWDW_DLV_ERROR\fP on error. 
\f(CWdwarf_loclist()\fP works on \f(CWDW_AT_location\fP, 
\f(CWDW_AT_data_member_location\fP, \f(CWDW_AT_vtable_elem_location\fP,
\f(CWDW_AT_string_length\fP, \f(CWDW_AT_use_location\fP, and 
\f(CWDW_AT_return_addr\fP attributes.  
.P
Storage allocated by a successful call of \f(CWdwarf_loclist()\fP should 
be deallocated when no longer of interest (see \f(CWdwarf_dealloc()\fP).
The block of \f(CWDwarf_Loc\fP structs pointed to by the \f(CWld_s\fP 
field of each \f(CWDwarf_Locdesc\fP structure 
should be deallocated with the allocation type \f(CWDW_DLA_LOC_BLOCK\fP. 
This should be followed by deallocation of the \f(CWllbuf\fP
using the allocation type \f(CWDW_DLA_LOCDESC\fP.
.in +2
.DS
\f(CWDwarf_Signed lcnt;
Dwarf_Locdesc *llbuf;
int lres;

lres = dwarf_loclist(someattr, &llbuf,&lcnt,&error);
if (lres == DW_DLV_OK) {
	/* lcnt is always 1, (and has always been 1) */ */

	/* Use llbuf here. */


        dwarf_dealloc(dbg, llbuf->ld_s, DW_DLA_LOC_BLOCK);
        dwarf_dealloc(dbg, llbuf, DW_DLA_LOCDESC);
/*      Earlier version. 
*         for (i = 0; i < lcnt; ++i) {
*             /* use llbuf[i] */
* 
*             /* Deallocate Dwarf_Loc block of llbuf[i] */
*             dwarf_dealloc(dbg, llbuf[i].ld_s, DW_DLA_LOC_BLOCK);
*         }
*         dwarf_dealloc(dbg, llbuf, DW_DLA_LOCDESC);
*/

}\fP
.DE
.in -2
.P

.H 3 "dwarf_loclist_from_expr()"
.DS
\f(CWint dwarf_loclist_from_expr(
        Dwarf_Ptr bytes_in, 
        Dwarf_Unsigned bytes_len,
        Dwarf_Locdesc **llbuf,
        Dwarf_Signed  *listlen,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_loclist_from_expr()\fP sets \f(CW*llbuf\fP to point to 
a \f(CWDwarf_Locdesc\fP pointer for the single location expression
which is pointed to by \f(CW*bytes_in\fP (whose length is
\f(CW*bytes_len\fP).
It sets
\f(CW*listlen\fP to 1.
and returns \f(CWDW_DLV_OK\fP 
if decoding is successful.
Some sources of bytes of expressions are dwarf expressions
in frame operations like \f(CWDW_CFA_def_cfa_expression\fP,
\f(CWDW_CFA_expression\fP, and  \f(CWDW_CFA_val_expression\fP.
.P
Any address_size data in the location expression is assumed
to be the same size as the default address_size for the object
being read (normally 4 or 8).
.P
It returns \f(CWDW_DLV_ERROR\fP on error. 
.P
Storage allocated by a successful call of \f(CWdwarf_loclist_from_expr()\fP should 
be deallocated when no longer of interest (see \f(CWdwarf_dealloc()\fP).
The block of \f(CWDwarf_Loc\fP structs pointed to by the \f(CWld_s\fP 
field of each \f(CWDwarf_Locdesc\fP structure 
should be deallocated with the allocation type \f(CWDW_DLA_LOC_BLOCK\fP. 
This should be followed by deallocation of the \f(CWllbuf\fP
using the allocation type \f(CWDW_DLA_LOCDESC\fP.
.in +2
.DS
\f(CWDwarf_Signed lcnt;
Dwarf_Locdesc *llbuf;
int lres;
/* Example with an empty buffer here. */
Dwarf_Ptr data = "";
Dwarf_Unsigned len = 0;

lres = dwarf_loclist_from_expr(data,len, &llbuf,&lcnt, &error);
if (lres == DW_DLV_OK) {
	/* lcnt is always 1 */

	/* Use llbuf  here.*/

        dwarf_dealloc(dbg, llbuf->ld_s, DW_DLA_LOC_BLOCK);
        dwarf_dealloc(dbg, llbuf, DW_DLA_LOCDESC);

}\fP
.DE
.in -2
.P

.H 3 "dwarf_loclist_from_expr_a()"
.DS
\f(CWint dwarf_loclist_from_expr_a(
        Dwarf_Ptr bytes_in, 
        Dwarf_Unsigned bytes_len,
        Dwarf_Half addr_size,
        Dwarf_Locdesc **llbuf,
        Dwarf_Signed  *listlen,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_loclist_from_expr_a()\fP 
is identical to  \f(CWdwarf_loclist_from_expr()\fP
in every way except that the caller passes the additional argument 
\f(CWaddr_size\fP containing the address size (normally 4 or 8)
applying this location expression.
.P
The \f(CWaddr_size\fP argument (added 27April2009) is needed
to correctly interpret frame information as different compilation
units can have different address sizes.
DWARF4 adds address_size to the CIE header.

.P
.H 2 "Line Number Operations"
These functions are concerned with accessing line number entries,
mapping debugging information entry objects to their corresponding
source lines, and providing a mechanism for obtaining information
about line number entries.  Although, the interface talks of "lines"
what is really meant is "statements".  In case there is more than
one statement on the same line, there will be at least one descriptor
per statement, all with the same line number.  If column number is
also being represented they will have the column numbers of the start
of the statements also represented.
.P
There can also be more than one Dwarf_Line per statement.
For example, if a file is preprocessed by a language translator,
this could result in translator output showing 2 or more sets of line
numbers per translated line of output.

.H 3 "Get A Set of Lines"
The function returns information about every source line for a 
particular compilation-unit.  
The compilation-unit is specified
by the corresponding die.
.H 4 "dwarf_srclines()"
.DS
\f(CWint dwarf_srclines(
        Dwarf_Die die, 
        Dwarf_Line **linebuf, 
	Dwarf_Signed *linecount,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_srclines()\fP places all line number descriptors 
for a single compilation unit into a single block, sets \f(CW*linebuf\fP 
to point to that block, 
sets \f(CW*linecount\fP to the number of descriptors in this block
and returns \f(CWDW_DLV_OK\fP.
The compilation-unit is indicated by the given \f(CWdie\fP which must be
a compilation-unit die.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
On
successful return, line number information 
should be freed using \f(CWdwarf_srclines_dealloc()\fP
when no longer of interest. 
.P
.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Line *linebuf;
int sres;

sres = dwarf_srclines(somedie, &linebuf,&cnt, &error);
if (sres == DW_DLV_OK) {
        for (i = 0; i < cnt; ++i) {
                /* use linebuf[i] */
        }
        dwarf_srclines_dealloc(dbg, linebuf, cnt);
}\fP
.DE

.in -2
.P
The following dealloc code (the only documented method before July 2005)
still works, but does not completely free all data allocated.
The \f(CWdwarf_srclines_dealloc()\fP routine was created
to fix the problem of incomplete deallocation.
.P
.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Line *linebuf;
int sres;

sres = dwarf_srclines(somedie, &linebuf,&cnt, &error);
if (sres == DW_DLV_OK) {
        for (i = 0; i < cnt; ++i) {
                /* use linebuf[i] */
                dwarf_dealloc(dbg, linebuf[i], DW_DLA_LINE);
        }
        dwarf_dealloc(dbg, linebuf, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 3 "Get the set of Source File Names"

The function returns the names of the source files that have contributed
to the compilation-unit represented by the given DIE.  Only the source
files named in the statement program prologue are returned.


.DS
\f(CWint dwarf_srcfiles(
        Dwarf_Die die,
        char ***srcfiles,
        Dwarf_Signed *srccount,
        Dwarf_Error *error)\fP
.DE
When it succeeds
\f(CWdwarf_srcfiles()\fP returns 
\f(CWDW_DLV_OK\fP
and
puts
the number of source
files named in the statement program prologue indicated by the given
\f(CWdie\fP
into \f(CW*srccount\fP.  
Source files defined in the statement program are ignored.
The given \f(CWdie\fP should have the tag 
\f(CWDW_TAG_compile_unit\fP,
\f(CWDW_TAG_partial_unit\fP,
or \f(CWDW_TAG_type_unit\fP
.
The location pointed to by \f(CWsrcfiles\fP is set to point to a list
of pointers to null-terminated strings that name the source
files.  
On a successful return from this function, each of the
strings returned should be individually freed using \f(CWdwarf_dealloc()\fP
with the allocation type \f(CWDW_DLA_STRING\fP when no longer of
interest.  
This should be followed by free-ing the list using
\f(CWdwarf_dealloc()\fP with the allocation type \f(CWDW_DLA_LIST\fP.
It returns \f(CWDW_DLV_ERROR\fP on error. 
It returns \f(CWDW_DLV_NO_ENTRY\fP
if there is no
corresponding statement program (i.e., if there is no line information).
.in +2
.DS
\f(CWDwarf_Signed cnt;
char **srcfiles;
int res;

res = dwarf_srcfiles(somedie, &srcfiles,&cnt &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use srcfiles[i] */
                dwarf_dealloc(dbg, srcfiles[i], DW_DLA_STRING);
        }
        dwarf_dealloc(dbg, srcfiles, DW_DLA_LIST);
}\fP
.DE
.in -2
.H 3 "Get information about a Single Table Line"
The following functions can be used on the \f(CWDwarf_Line\fP descriptors
returned by \f(CWdwarf_srclines()\fP to obtain information about the
source lines.

.H 4 "dwarf_linebeginstatement()"
.DS
\f(CWint dwarf_linebeginstatement(
        Dwarf_Line line, 
	Dwarf_Bool *return_bool,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_linebeginstatement()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_bool\fP
to
\fInon-zero\fP 
(if \f(CWline\fP represents a line number entry that is marked as
beginning a statement).  
or
\fIzero\fP ((if \f(CWline\fP represents a line number entry
that is not marked as beginning a statement).
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.P
.H 4 "dwarf_lineendsequence()"
.DS
\f(CWint dwarf_lineendsequence(
	Dwarf_Line line,
	Dwarf_Bool *return_bool,
	Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_lineendsequence()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_bool\fP
\fInon-zero\fP
(in which case 
\f(CWline\fP represents a line number entry that is marked as
ending a text sequence)
or
\fIzero\fP (in which case 
\f(CWline\fP represents a line number entry
that is not marked as ending a text sequence).
A line number entry that is marked as
ending a text sequence is an entry with an address 
one beyond the highest address used by the current
sequence of line table entries (that is, the table entry is
a DW_LNE_end_sequence entry (see the DWARF specification)).
.P
The function \f(CWdwarf_lineendsequence()\fP 
returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.P
.H 4 "dwarf_lineno()"
.DS
\f(CWint dwarf_lineno(
        Dwarf_Line       line, 
	Dwarf_Unsigned * returned_lineno,
        Dwarf_Error    * error)\fP
.DE
The function \f(CWdwarf_lineno()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_lineno\fP to
the source statement line 
number corresponding to the descriptor \f(CWline\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.P
.H 4 "dwarf_line_srcfileno()"
.DS
\f(CWint dwarf_line_srcfileno(
        Dwarf_Line       line, 
	Dwarf_Unsigned * returned_fileno,
        Dwarf_Error    * error)\fP
.DE
The function \f(CWdwarf_line_srcfileno()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_fileno\fP to
the source statement line 
number corresponding to the descriptor \f(CWfile number\fP.  
When the number returned through \f(CW*returned_fileno\fP is zero it means
the file name is unknown (see the DWARF2/3 line table specification).
When the number returned through \f(CW*returned_fileno\fP is non-zero
it is a file number:
subtract 1 from this file number
to get an
index into the array of strings returned by \f(CWdwarf_srcfiles()\fP
(verify the resulting index is in range for the array of strings
before indexing into the array of strings).
The file number may exceed the size of 
the array of strings returned by \f(CWdwarf_srcfiles()\fP
because \f(CWdwarf_srcfiles()\fP does not return files names defined with
the  \f(CWDW_DLE_define_file\fP  operator.
The function \f(CWdwarf_line_srcfileno()\fP returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.P
.H 4 "dwarf_lineaddr()"
.DS
\f(CWint dwarf_lineaddr(
        Dwarf_Line   line, 
	Dwarf_Addr  *return_lineaddr,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_lineaddr()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_lineaddr\fP to
the address associated 
with the descriptor \f(CWline\fP.  
It returns \f(CWDW_DLV_ERROR\fP  on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.P
.H 4 "dwarf_lineoff()"
.DS
\f(CWint dwarf_lineoff(
        Dwarf_Line line, 
	Dwarf_Signed   * return_lineoff,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_lineoff()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_lineoff\fP to
the column number at which
the statement represented by \f(CWline\fP begins.  
.P
It sets \f(CWreturn_lineoff\fP to zero
if the column number of the statement is not represented
(meaning the producer library call was given zero
as the column number).  Zero is the correct value meaning "left edge" 
as defined in the DWARF2/3/4 specication (section 6.2.2).
.P
Before December 2011 zero was not returned through 
the  \f(CWreturn_lineoff\fP pointer, -1 was returned through the pointer.
The reason for this oddity is unclear, lost in history.
But there is no good reason for -1.
.P
The type of  \f(CWreturn_lineoff\fP is a pointer-to-signed, but there
is no good reason for the value to be signed, the DWARF specification
does not deal with negative column numbers.  However, changing the
declaration would cause compilation errors for little benefit, so
the pointer-to-signed is left unchanged.
.P
On error it returns \f(CWDW_DLV_ERROR\fP.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_linesrc()"
.DS
\f(CWint dwarf_linesrc(
        Dwarf_Line line, 
	char  **   return_linesrc,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_linesrc()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_linesrc\fP to
a pointer to a
null-terminated string of characters that represents the name of the 
source-file where \f(CWline\fP occurs.  
It returns \f(CWDW_DLV_ERROR\fP on 
error.  
.P
If the applicable file name in the line table Statement Program Prolog 
does not start with a '/' character
the string in \f(CWDW_AT_comp_dir\fP (if applicable and present)
or the applicable
directory name from the line Statement Program Prolog 
is prepended to the
file name in the line table Statement Program Prolog
to make a full path.
.P
The storage pointed to by a successful return of 
\f(CWdwarf_linesrc()\fP should be freed using \f(CWdwarf_dealloc()\fP with
the allocation type \f(CWDW_DLA_STRING\fP when no longer of interest.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_lineblock()"
.DS
\f(CWint dwarf_lineblock(
        Dwarf_Line line, 
	Dwarf_Bool *return_bool,
        Dwarf_Error *error)\fP
.DE
The function
\f(CWdwarf_lineblock()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_linesrc\fP to
non-zero (i.e. true)(if the line is marked as 
beginning a basic block)
or zero (i.e. false) (if the line is marked as not
beginning a basic block).  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_is_addr_set()"
.DS
\f(CWint dwarf_line_is_addr_set(
        Dwarf_Line line, 
	Dwarf_Bool *return_bool,
        Dwarf_Error *error)\fP
.DE
The function
\f(CWdwarf_line_is_addr_set()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_bool\fP to
non-zero (i.e. true)(if the line is marked as 
being a DW_LNE_set_address operation)
or zero (i.e. false) (if the line is marked as not
being a DW_LNE_set_address operation).  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

This is intended to allow consumers to do a more useful job
printing and analyzing DWARF data, it is not strictly
necessary.

.H 4 "dwarf_prologue_end_etc()" 
.DS
\f(CWint dwarf_prologue_end_etc(Dwarf_Line  line,
        Dwarf_Bool  *    prologue_end,
        Dwarf_Bool  *    epilogue_begin,
        Dwarf_Unsigned * isa,
        Dwarf_Unsigned * discriminator,
        Dwarf_Error *    error)\fP
.DE
The function 
\f(CWdwarf_prologue_end_etc()\fP returns
\f(CWDW_DLV_OK\fP and sets  the returned fields to
values currently set.
While it is pretty safe to assume that the
\f(CWisa\fP
and
\f(CWdiscriminator\fP
values returned are very small integers, there is
no restriction in the standard.
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

This function is new in December 2011.


.H 2 "Global Name Space Operations" 
These operations operate on the .debug_pubnames section of the debugging 
information.


.H 2 "Global Name Space Operations" 
These operations operate on the .debug_pubnames section of the debugging 
information.

.H 3 "Debugger Interface Operations"

.H 4 "dwarf_get_globals()"
.DS
\f(CWint dwarf_get_globals(
        Dwarf_Debug dbg,
        Dwarf_Global **globals,
        Dwarf_Signed * return_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_globals()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_count\fP to
the count of pubnames
represented in the section containing pubnames i.e. .debug_pubnames.
It also stores at \f(CW*globals\fP, a pointer 
to a list of \f(CWDwarf_Global\fP descriptors, one for each of the 
pubnames in the .debug_pubnames section.  
The returned results are for the entire section.
It returns \f(CWDW_DLV_ERROR\fP on error. 
It returns \f(CWDW_DLV_NO_ENTRY\fP if the .debug_pubnames 
section does not exist.

.P
On a successful return from
\f(CWdwarf_get_globals()\fP, the \f(CWDwarf_Global\fP 
descriptors should be
freed using \f(CWdwarf_globals_dealloc()\fP.
\f(CWdwarf_globals_dealloc()\fP is new as of July 15, 2005
and is the preferred approach to freeing this memory..

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Global *globs;
int res;

res = dwarf_get_globals(dbg, &globs,&cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use globs[i] */
        }
        dwarf_globals_dealloc(dbg, globs, cnt);
}\fP
.DE
.in -2


.P
The following code is deprecated as of July 15, 2005 as it does not
free all relevant memory.
This approach  still works as well as it ever did.
On a successful return from 
\f(CWdwarf_get_globals()\fP, the \f(CWDwarf_Global\fP 
descriptors should be individually 
freed using \f(CWdwarf_dealloc()\fP with the allocation type 
\f(CWDW_DLA_GLOBAL_CONTEXT\fP, 
(or
\f(CWDW_DLA_GLOBAL\fP, an older name, supported for compatibility)
followed by the deallocation of the list itself 
with the allocation type \f(CWDW_DLA_LIST\fP when the descriptors are 
no longer of interest.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Global *globs;
int res;

res = dwarf_get_globals(dbg, &globs,&cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use globs[i] */
                dwarf_dealloc(dbg, globs[i], DW_DLA_GLOBAL_CONTEXT);
        }
        dwarf_dealloc(dbg, globs, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 4 "dwarf_globname()"
.DS
\f(CWint dwarf_globname(
        Dwarf_Global global,
        char **      return_name,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_globname()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP to
a pointer to a 
null-terminated string that names the pubname represented by the 
\f(CWDwarf_Global\fP descriptor, \f(CWglobal\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
On a successful return from this function, the string should
be freed using \f(CWdwarf_dealloc()\fP, with the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_global_die_offset()"
.DS
\f(CWint dwarf_global_die_offset(
        Dwarf_Global global,
	Dwarf_Off   *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_global_die_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the DIE representing
the pubname that is described by the \f(CWDwarf_Global\fP descriptor, 
\f(CWglob\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_global_cu_offset()"
.DS
\f(CWint dwarf_global_cu_offset(
        Dwarf_Global global,
	Dwarf_Off   *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_global_cu_offset()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the compilation-unit
header of the compilation-unit that contains the pubname described 
by the \f(CWDwarf_Global\fP descriptor, \f(CWglobal\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_get_cu_die_offset_given_cu_header_offset()"
.DS
\f(CWint dwarf_get_cu_die_offset_given_cu_header_offset_b(
	Dwarf_Debug dbg,
	Dwarf_Off   in_cu_header_offset,
        Dwarf_Bool  is_info,
        Dwarf_Off * out_cu_die_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_cu_die_offset_given_cu_header_offset()\fP 
returns
\f(CWDW_DLV_OK\fP and sets \f(CW*out_cu_die_offset\fP to
the offset of the compilation-unit DIE given the
offset \f(CWin_cu_header_offset\fP of a compilation-unit header.
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
.P
If \f(CWis_info\fP is non-zero the \f(CWin_cu_header_offset\fP must refer
to a .debug_info section offset. 
If \f(CWis_info\fP zero the \f(CWin_cu_header_offset\fP must refer
to a .debug_types section offset. 
Chaos may result if the \f(CWis_info\fP flag is incorrect.

This effectively turns a compilation-unit-header offset
into a compilation-unit DIE offset (by adding the
size of the applicable CU header).
This function is also sometimes useful with the 
\f(CWdwarf_weak_cu_offset()\fP,
\f(CWdwarf_func_cu_offset()\fP,
\f(CWdwarf_type_cu_offset()\fP,
and
\f(CWint dwarf_var_cu_offset()\fP 
functions, though for those functions the data is
only in .debug_info by definition.

.H 4 "dwarf_get_cu_die_offset_given_cu_header_offset()"
.DS
\f(CWint dwarf_get_cu_die_offset_given_cu_header_offset(
	Dwarf_Debug dbg,
	Dwarf_Off   in_cu_header_offset,
        Dwarf_Off * out_cu_die_offset,
        Dwarf_Error *error)\fP
.DE
This function is superseded by 
\f(CWdwarf_get_cu_die_offset_given_cu_header_offset_b()\fP,
a function which is still supported thought it refers only
to the .debug_info section.


\f(CWdwarf_get_cu_die_offset_given_cu_header_offset()\fP 
added Rev 1.45, June, 2001.

This function is declared as 'optional' in libdwarf.h
on IRIX systems so the _MIPS_SYMBOL_PRESENT
predicate may be used at run time to determine if the version of
libdwarf linked into an application has this function.

.H 4 "dwarf_global_name_offsets()"
.DS
\f(CWint dwarf_global_name_offsets(
        Dwarf_Global global,
        char     **return_name,
        Dwarf_Off *die_offset,
        Dwarf_Off *cu_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_global_name_offsets()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP to
a pointer to
a null-terminated string that gives the name of the pubname
described by the \f(CWDwarf_Global\fP descriptor \f(CWglobal\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
It also returns in the locations 
pointed to by \f(CWdie_offset\fP, and \f(CWcu_offset\fP, the offsets
of the DIE representing the 
pubname, and the DIE
representing the compilation-unit containing the 
pubname, respectively.
On a 
successful return from \f(CWdwarf_global_name_offsets()\fP the storage 
pointed to by \f(CWreturn_name\fP 
should be freed using \f(CWdwarf_dealloc()\fP, 
with the allocation type \f(CWDW_DLA_STRING\fP when no longer of interest.


.H 2 "DWARF3 Type Names Operations"
Section ".debug_pubtypes" is new in DWARF3.
.P
These functions operate on the .debug_pubtypes section of the debugging
information.  The .debug_pubtypes section contains the names of file-scope
user-defined types, the offsets of the \f(CWDIE\fPs that represent the
definitions of those types, and the offsets of the compilation-units 
that contain the definitions of those types.

.H 3 "Debugger Interface Operations"

.H 4 "dwarf_get_pubtypes()"
.DS
\f(CWint dwarf_get_pubtypes(
        Dwarf_Debug dbg,
        Dwarf_Type **types,
        Dwarf_Signed *typecount,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_pubtypes()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*typecount\fP to
the count of user-defined
type names represented in the section containing user-defined type names,
i.e. .debug_pubtypes.
It also stores at \f(CW*types\fP, 
a pointer to a list of \f(CWDwarf_Pubtype\fP descriptors, one for each of the 
user-defined type names in the .debug_pubtypes section.  
The returned results are for the entire section.
It returns \f(CWDW_DLV_NOCOUNT\fP on error. 
It returns \f(CWDW_DLV_NO_ENTRY\fP if 
the .debug_pubtypes section does not exist.  

.P
On a successful 
return from \f(CWdwarf_get_pubtypes()\fP, 
the \f(CWDwarf_Type\fP descriptors should be 
freed using \f(CWdwarf_types_dealloc()\fP.
\f(CWdwarf_types_dealloc()\fP is used for both
\f(CWdwarf_get_pubtypes()\fP and \f(CWdwarf_get_types()\fP
as the data types are the same.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Pubtype *types;
int res;

res = dwarf_get_pubtypes(dbg, &types,&cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use types[i] */
        }
        dwarf_types_dealloc(dbg, types, cnt);
}\fP
.DE
.in -2

.H 4 "dwarf_pubtypename()"
.DS
\f(CWint dwarf_pubtypename(
        Dwarf_Pubtype   type,
        char       **return_name,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_pubtypename()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP to
a pointer to a
null-terminated string that names the user-defined type represented by the
\f(CWDwarf_Pubtype\fP descriptor, \f(CWtype\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from this function, the string should
be freed using \f(CWdwarf_dealloc()\fP, with the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest.

.H 4 "dwarf_pubtype_die_offset()"
.DS
\f(CWint dwarf_pubtype_die_offset(
        Dwarf_Pubtype type,
        Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_pubtype_die_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the DIE representing
the user-defined type that is described by the \f(CWDwarf_Pubtype\fP 
descriptor, \f(CWtype\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_pubtype_cu_offset()"
.DS
\f(CWint dwarf_pubtype_cu_offset(
        Dwarf_Pubtype type,
        Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_pubtype_cu_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the compilation-unit
header of the compilation-unit that contains the user-defined type
described by the \f(CWDwarf_Pubtype\fP descriptor, \f(CWtype\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_pubtype_name_offsets()"
.DS
\f(CWint dwarf_pubtype_name_offsets(
        Dwarf_Pubtype   type,
        char      ** returned_name,
        Dwarf_Off *  die_offset,
        Dwarf_Off *  cu_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_pubtype_name_offsets()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_name\fP to
a pointer to
a null-terminated string that gives the name of the user-defined
type described by the \f(CWDwarf_Pubtype\fP descriptor \f(CWtype\fP.
It also returns in the locations
pointed to by \f(CWdie_offset\fP, and \f(CWcu_offset\fP, the offsets
of the DIE representing the 
user-defined type, and the DIE
representing the compilation-unit containing the 
user-defined type, respectively.
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from \f(CWdwarf_pubtype_name_offsets()\fP
the storage pointed to by \f(CWreturned_name\fP should
be freed using
\f(CWdwarf_dealloc()\fP, with the allocation type \f(CWDW_DLA_STRING\fP
when no longer of interest.


.H 2 "User Defined Static Variable Names Operations"
This section is SGI specific and is not part of standard DWARF version 2.
.P
These functions operate on the .debug_varnames section of the debugging
information.  The .debug_varnames section contains the names of file-scope
static variables, the offsets of the \f(CWDIE\fPs that represent the 
definitions of those variables, and the offsets of the compilation-units
that contain the definitions of those variables.
.P


.H 2 "Weak Name Space Operations" 
These operations operate on the .debug_weaknames section of the debugging 
information.
.P
These operations are SGI specific, not part of standard DWARF.
.P

.H 3 "Debugger Interface Operations"

.H 4 "dwarf_get_weaks()"
.DS
\f(CWint dwarf_get_weaks(
        Dwarf_Debug dbg,
        Dwarf_Weak **weaks,
	Dwarf_Signed *weak_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_weaks()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*weak_count\fP to
the count of weak names
represented in the section containing weak names i.e. .debug_weaknames.
It returns \f(CWDW_DLV_ERROR\fP on error. 
It returns \f(CWDW_DLV_NO_ENTRY\fP if the section does not exist.  
It also stores in \f(CW*weaks\fP, a pointer to 
a list of \f(CWDwarf_Weak\fP descriptors, one for each of the weak names 
in the .debug_weaknames section.  
The returned results are for the entire section.

.P
On a successful return from this function,
the \f(CWDwarf_Weak\fP descriptors should be freed using
\f(CWdwarf_weaks_dealloc()\fP when the data is no longer of
interest.  \f(CWdwarf_weaks_dealloc()\fPis new as of July 15, 2005.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Weak *weaks;
int res;

res = dwarf_get_weaks(dbg, &weaks, &cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use weaks[i] */
        }
        dwarf_weaks_dealloc(dbg, weaks, cnt);
}\fP
.DE
.in -2



.P
The following code is deprecated as of July 15, 2005 as it does not
free all relevant memory.
This approach  still works as well as it ever did.
On a successful return from \f(CWdwarf_get_weaks()\fP
the \f(CWDwarf_Weak\fP descriptors should be individually freed using 
\f(CWdwarf_dealloc()\fP with the allocation type 
\f(CWDW_DLA_WEAK_CONTEXT\fP, 
(or
\f(CWDW_DLA_WEAK\fP, an older name, supported for compatibility)
followed by the deallocation of the list itself with the allocation type 
\f(CWDW_DLA_LIST\fP when the descriptors are no longer of interest.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Weak *weaks;
int res;

res = dwarf_get_weaks(dbg, &weaks, &cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use weaks[i] */
                dwarf_dealloc(dbg, weaks[i], DW_DLA_WEAK_CONTEXT);
        }
        dwarf_dealloc(dbg, weaks, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 4 "dwarf_weakname()"
.DS
\f(CWint dwarf_weakname(
        Dwarf_Weak weak,
	char    ** return_name,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_weakname()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP to
a pointer to a null-terminated
string that names the weak name represented by the 
\f(CWDwarf_Weak\fP descriptor, \f(CWweak\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from this function, the string should
be freed using \f(CWdwarf_dealloc()\fP, with the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest.

.DS
\f(CWint dwarf_weak_die_offset(
        Dwarf_Weak weak,
	Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_weak_die_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to the offset in
the section containing DIEs, i.e. .debug_info, of the DIE representing
the weak name that is described by the \f(CWDwarf_Weak\fP descriptor, 
\f(CWweak\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_weak_cu_offset()"
.DS
\f(CWint dwarf_weak_cu_offset(
        Dwarf_Weak weak,
	Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_weak_cu_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to the offset in
the section containing DIEs, i.e. .debug_info, of the compilation-unit
header of the compilation-unit that contains the weak name described 
by the \f(CWDwarf_Weak\fP descriptor, \f(CWweak\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_weak_name_offsets()"
.DS
\f(CWint dwarf_weak_name_offsets(
        Dwarf_Weak weak,
	char **  weak_name,
        Dwarf_Off *die_offset,
        Dwarf_Off *cu_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_weak_name_offsets()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*weak_name\fP to
a pointer to
a null-terminated string that gives the name of the weak name
described by the \f(CWDwarf_Weak\fP descriptor \f(CWweak\fP.  
It also returns in the locations 
pointed to by \f(CWdie_offset\fP, and \f(CWcu_offset\fP, the offsets
of the DIE representing the 
weakname, and the DIE
representing the compilation-unit containing the 
weakname, respectively.
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a 
successful return from \f(CWdwarf_weak_name_offsets()\fP the storage 
pointed to by \f(CWweak_name\fP
should be freed using \f(CWdwarf_dealloc()\fP, 
with the allocation type \f(CWDW_DLA_STRING\fP when no longer of interest.

.H 2 "Static Function Names Operations"
This section is SGI specific and is not part of standard DWARF version 2.
.P
These function operate on the .debug_funcnames section of the debugging
information.  The .debug_funcnames section contains the names of static
functions defined in the object, the offsets of the \f(CWDIE\fPs that
represent the definitions of the corresponding functions, and the offsets
of the start of the compilation-units that contain the definitions of
those functions.

.H 3 "Debugger Interface Operations"

.H 4 "dwarf_get_funcs()"
.DS
\f(CWint dwarf_get_funcs(
        Dwarf_Debug dbg,
        Dwarf_Func **funcs,
        Dwarf_Signed *func_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_funcs()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*func_count\fP to
the count of static
function names represented in the section containing static function
names, i.e. .debug_funcnames.
It also 
stores, at \f(CW*funcs\fP, a pointer to a list of \f(CWDwarf_Func\fP 
descriptors, one for each of the static functions in the .debug_funcnames 
section.  
The returned results are for the entire section.
It returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP
if the .debug_funcnames section does not exist.  
.P
On a successful return from \f(CWdwarf_get_funcs()\fP, 
the \f(CWDwarf_Func\fP
descriptors should be freed using \f(CWdwarf_funcs_dealloc()\fP.
\f(CWdwarf_funcs_dealloc()\fP is new as of July 15, 2005.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Func *funcs;
int fres;

fres = dwarf_get_funcs(dbg, &funcs, &cnt, &error);
if (fres == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use funcs[i] */
        }
        dwarf_funcs_dealloc(dbg, funcs, cnt);
}\fP
.DE
.in -2


.P
The following code is deprecated as of July 15, 2005 as it does not
free all relevant memory.
This approach  still works as well as it ever did.
On a successful return from \f(CWdwarf_get_funcs()\fP, 
the \f(CWDwarf_Func\fP 
descriptors should be individually freed using \f(CWdwarf_dealloc()\fP 
with the allocation type 
\f(CWDW_DLA_FUNC_CONTEXT\fP, 
(or
\f(CWDW_DLA_FUNC\fP, an older name, supported for compatibility)
followed by the deallocation 
of the list itself with the allocation type \f(CWDW_DLA_LIST\fP when 
the descriptors are no longer of interest.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Func *funcs;
int fres;

fres = dwarf_get_funcs(dbg, &funcs, &error);
if (fres == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use funcs[i] */
                dwarf_dealloc(dbg, funcs[i], DW_DLA_FUNC_CONTEXT);
        }
        dwarf_dealloc(dbg, funcs, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 4 "dwarf_funcname()"
.DS
\f(CWint dwarf_funcname(
        Dwarf_Func func,
        char **    return_name,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_funcname()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP to
a pointer to a
null-terminated string that names the static function represented by the
\f(CWDwarf_Func\fP descriptor, \f(CWfunc\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from this function, the string should
be freed using \f(CWdwarf_dealloc()\fP, with the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest.

.H 4 "dwarf_func_die_offset()"
.DS
\f(CWint dwarf_func_die_offset(
        Dwarf_Func func,
	Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_func_die_offset()\fP, returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the DIE representing
the static function that is described by the \f(CWDwarf_Func\fP 
descriptor, \f(CWfunc\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_func_cu_offset()"
.DS
\f(CWint dwarf_func_cu_offset(
        Dwarf_Func func,
	Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_func_cu_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the compilation-unit
header of the 
compilation-unit that contains the static function
described by the \f(CWDwarf_Func\fP descriptor, \f(CWfunc\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_func_name_offsets()"
.DS
\f(CWint dwarf_func_name_offsets(
        Dwarf_Func func,
	char     **func_name,
        Dwarf_Off *die_offset,
        Dwarf_Off *cu_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_func_name_offsets()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*func_name\fP to
a pointer to
a null-terminated string that gives the name of the static
function described by the \f(CWDwarf_Func\fP descriptor \f(CWfunc\fP.
It also returns in the locations
pointed to by \f(CWdie_offset\fP, and \f(CWcu_offset\fP, the offsets
of the DIE representing the 
static function, and the DIE
representing the compilation-unit containing the 
static function, respectively.
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from \f(CWdwarf_func_name_offsets()\fP
the storage pointed to by  \f(CWfunc_name\fP should be freed using
\f(CWdwarf_dealloc()\fP, with the allocation type \f(CWDW_DLA_STRING\fP
when no longer of interest.

.H 2 "User Defined Type Names Operations"
Section "debug_typenames" is SGI specific 
and is not part of standard DWARF version 2.
(However, an identical section is part of DWARF version 3
named ".debug_pubtypes", see  \f(CWdwarf_get_pubtypes()\fP above.)
.P
These functions operate on the .debug_typenames section of the debugging
information.  The .debug_typenames section contains the names of file-scope
user-defined types, the offsets of the \f(CWDIE\fPs that represent the
definitions of those types, and the offsets of the compilation-units 
that contain the definitions of those types.

.H 3 "Debugger Interface Operations"

.H 4 "dwarf_get_types()"
.DS
\f(CWint dwarf_get_types(
        Dwarf_Debug dbg,
        Dwarf_Type **types,
        Dwarf_Signed *typecount,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_types()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*typecount\fP to
the count of user-defined
type names represented in the section containing user-defined type names,
i.e. .debug_typenames.
It also stores at \f(CW*types\fP, 
a pointer to a list of \f(CWDwarf_Type\fP descriptors, one for each of the 
user-defined type names in the .debug_typenames section.  
The returned results are for the entire section.
It returns \f(CWDW_DLV_NOCOUNT\fP on error. 
It returns \f(CWDW_DLV_NO_ENTRY\fP if 
the .debug_typenames section does not exist.  

.P

On a successful
return from \f(CWdwarf_get_types()\fP, 
the \f(CWDwarf_Type\fP descriptors should be
freed using \f(CWdwarf_types_dealloc()\fP.
\f(CWdwarf_types_dealloc()\fP is new as of July 15, 2005
and frees all memory allocated by \f(CWdwarf_get_types()\fP.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Type *types;
int res;

res = dwarf_get_types(dbg, &types,&cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use types[i] */
        }
        dwarf_types_dealloc(dbg, types, cnt);
}\fP
.DE
.in -2



.P
The following code is deprecated as of July 15, 2005 as it does not
free all relevant memory.
This approach  still works as well as it ever did.
On a successful 
return from \f(CWdwarf_get_types()\fP, 
the \f(CWDwarf_Type\fP descriptors should be 
individually freed using \f(CWdwarf_dealloc()\fP with the allocation type 
\f(CWDW_DLA_TYPENAME_CONTEXT\fP, 
(or
\f(CWDW_DLA_TYPENAME\fP, an older name, supported for compatibility)
followed by the deallocation of the list itself 
with the allocation type \f(CWDW_DLA_LIST\fP when the descriptors are no 
longer of interest.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Type *types;
int res;

res = dwarf_get_types(dbg, &types,&cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use types[i] */
                dwarf_dealloc(dbg, types[i], DW_DLA_TYPENAME_CONTEXT);
        }
        dwarf_dealloc(dbg, types, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 4 "dwarf_typename()"
.DS
\f(CWint dwarf_typename(
        Dwarf_Type   type,
        char       **return_name,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_typename()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_name\fP to
a pointer to a
null-terminated string that names the user-defined type represented by the
\f(CWDwarf_Type\fP descriptor, \f(CWtype\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from this function, the string should
be freed using \f(CWdwarf_dealloc()\fP, with the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest.

.H 4 "dwarf_type_die_offset()"
.DS
\f(CWint dwarf_type_die_offset(
        Dwarf_Type type,
        Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_type_die_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the DIE representing
the user-defined type that is described by the \f(CWDwarf_Type\fP 
descriptor, \f(CWtype\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_type_cu_offset()"
.DS
\f(CWint dwarf_type_cu_offset(
        Dwarf_Type type,
        Dwarf_Off  *return_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_type_cu_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the compilation-unit
header of the compilation-unit that contains the user-defined type
described by the \f(CWDwarf_Type\fP descriptor, \f(CWtype\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_type_name_offsets()"
.DS
\f(CWint dwarf_type_name_offsets(
        Dwarf_Type   type,
        char      ** returned_name,
        Dwarf_Off *  die_offset,
        Dwarf_Off *  cu_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_type_name_offsets()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_name\fP to
a pointer to
a null-terminated string that gives the name of the user-defined
type described by the \f(CWDwarf_Type\fP descriptor \f(CWtype\fP.
It also returns in the locations
pointed to by \f(CWdie_offset\fP, and \f(CWcu_offset\fP, the offsets
of the DIE representing the 
user-defined type, and the DIE
representing the compilation-unit containing the 
user-defined type, respectively.
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from \f(CWdwarf_type_name_offsets()\fP
the storage pointed to by \f(CWreturned_name\fP should
be freed using
\f(CWdwarf_dealloc()\fP, with the allocation type \f(CWDW_DLA_STRING\fP
when no longer of interest.


.H 2 "User Defined Static Variable Names Operations"
This section is SGI specific and is not part of standard DWARF version 2.
.P
These functions operate on the .debug_varnames section of the debugging
information.  The .debug_varnames section contains the names of file-scope
static variables, the offsets of the \f(CWDIE\fPs that represent the 
definitions of those variables, and the offsets of the compilation-units
that contain the definitions of those variables.
.P

.H 3 "Debugger Interface Operations"

.H 4 "dwarf_get_vars()"

.DS
\f(CWint dwarf_get_vars(
        Dwarf_Debug dbg,
        Dwarf_Var **vars,
        Dwarf_Signed *var_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_vars()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*var_count\fP to
the count of file-scope
static variable names represented in the section containing file-scope 
static variable names, i.e. .debug_varnames.
It also stores, at \f(CW*vars\fP, a pointer to a list of 
\f(CWDwarf_Var\fP descriptors, one for each of the file-scope static
variable names in the .debug_varnames section.  
The returned results are for the entire section.
It returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if the .debug_varnames section does 
not exist.  

.P 
The following is new as of July 15, 2005.
On a successful return
from \f(CWdwarf_get_vars()\fP, the \f(CWDwarf_Var\fP descriptors should be
freed using \f(CWdwarf_vars_dealloc()\fP.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Var *vars;
int res;

res = dwarf_get_vars(dbg, &vars,&cnt &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use vars[i] */
        }
        dwarf_vars_dealloc(dbg, vars, cnt);
}\fP
.DE
.in -2

.P 
The following code is deprecated as of July 15, 2005 as it does not
free all relevant memory.
This approach  still works as well as it ever did.
On a successful return 
from \f(CWdwarf_get_vars()\fP, the \f(CWDwarf_Var\fP descriptors should be individually 
freed using \f(CWdwarf_dealloc()\fP with the allocation type 
\f(CWDW_DLA_VAR_CONTEXT\fP, 
(or
\f(CWDW_DLA_VAR\fP, an older name, supported for compatibility)
followed by the deallocation of the list itself with 
the allocation type \f(CWDW_DLA_LIST\fP when the descriptors are no 
longer of interest.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Var *vars;
int res;

res = dwarf_get_vars(dbg, &vars,&cnt &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use vars[i] */
                dwarf_dealloc(dbg, vars[i], DW_DLA_VAR_CONTEXT);
        }
        dwarf_dealloc(dbg, vars, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 4 "dwarf_varname()"
.DS
\f(CWint dwarf_varname(
        Dwarf_Var var,
        char **    returned_name,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_varname()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_name\fP to
a pointer to a
null-terminated string that names the file-scope static variable represented 
by the \f(CWDwarf_Var\fP descriptor, \f(CWvar\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from this function, the string should
be freed using \f(CWdwarf_dealloc()\fP, with the allocation type
\f(CWDW_DLA_STRING\fP when no longer of interest.

.H 4 "dwarf_var_die_offset()"
.DS
\f(CWint dwarf_var_die_offset(
        Dwarf_Var    var,
        Dwarf_Off   *returned_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_var_die_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the DIE representing
the file-scope static variable that is described by the \f(CWDwarf_Var\fP 
descriptor, \f(CWvar\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_var_cu_offset()"
.DS
\f(CWint dwarf_var_cu_offset(
        Dwarf_Var var,
        Dwarf_Off   *returned_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_var_cu_offset()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_offset\fP to
the offset in
the section containing DIEs, i.e. .debug_info, of the compilation-unit
header of the compilation-unit that contains the file-scope static
variable described by the \f(CWDwarf_Var\fP descriptor, \f(CWvar\fP.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 4 "dwarf_var_name_offsets()"
.DS
\f(CWint dwarf_var_name_offsets(
        Dwarf_Var var,
	char     **returned_name,
        Dwarf_Off *die_offset,
        Dwarf_Off *cu_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_var_name_offsets()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_name\fP to
a pointer to
a null-terminated string that gives the name of the file-scope
static variable described by the \f(CWDwarf_Var\fP descriptor \f(CWvar\fP.
It also returns in the locations
pointed to by \f(CWdie_offset\fP, and \f(CWcu_offset\fP, the offsets
of the DIE representing the 
file-scope static variable, and the DIE
representing the compilation-unit containing the 
file-scope static variable, respectively.
It returns \f(CWDW_DLV_ERROR\fP on error.  
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
On a successful return from 
\f(CWdwarf_var_name_offsets()\fP the storage pointed to by
\f(CWreturned_name\fP
should be freed using \f(CWdwarf_dealloc()\fP, with the allocation 
type \f(CWDW_DLA_STRING\fP when no longer of interest.

.H 2 "Macro Information Operations"
.H 3 "General Macro Operations"
.H 4 "dwarf_find_macro_value_start()"
.DS
\f(CWchar *dwarf_find_macro_value_start(char * macro_string);\fP
.DE
Given a macro string in the standard form defined in the DWARF
document ("name <space> value" or "name(args)<space>value")
this returns a pointer to the first byte of the macro value.
It does not alter the string pointed to by macro_string or copy
the string: it returns a pointer into the string whose
address was passed in.
.H 3 "Debugger Interface Macro Operations"
Macro information is accessed from the .debug_info section via the
DW_AT_macro_info attribute (whose value is an offset into .debug_macinfo).
.P
No Functions yet defined.
.H 3 "Low Level Macro Information Operations"
.H 4 "dwarf_get_macro_details()"
.DS
\f(CWint dwarf_get_macro_details(Dwarf_Debug /*dbg*/,
  Dwarf_Off              macro_offset,
  Dwarf_Unsigned         maximum_count,
  Dwarf_Signed         * entry_count,
  Dwarf_Macro_Details ** details,
  Dwarf_Error *          err);\fP
.DE
\f(CWdwarf_get_macro_details()\fP
returns  
\f(CWDW_DLV_OK\fP and sets
\f(CWentry_count\fP to the number of \f(CWdetails\fP records
returned through the \f(CWdetails\fP pointer.
The data returned through  \f(CWdetails\fP should be freed
by a call to \f(CWdwarf_dealloc()\fP with the allocation type
\f(CWDW_DLA_STRING\fP.
If \f(CWDW_DLV_OK\fP is returned, the \f(CWentry_count\fP will
be at least 1, since
a compilation unit with macro information but no macros will
have at least one macro data byte of 0.
.P
\f(CWdwarf_get_macro_details()\fP
begins at the \f(CWmacro_offset\fP offset you supply
and ends at the end of a compilation unit or at \f(CWmaximum_count\fP
detail records (whichever comes first).
If \f(CWmaximum_count\fP is 0, it is treated as if it were the maximum
possible unsigned integer.
.P
\f(CWdwarf_get_macro_details()\fP
attempts to set \f(CWdmd_fileindex\fP to the correct file in every
\f(CWdetails\fP record. If it is unable to do so (or whenever
the current file index is unknown, it sets \f(CWdmd_fileindex\fP
to -1.
.P
\f(CWdwarf_get_macro_details()\fP returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if there is no more
macro information at that \f(CWmacro_offset\fP. If \f(CWmacro_offset\fP
is passed in as 0, a \f(CWDW_DLV_NO_ENTRY\fP return means there is
no macro information.
.P
.in +2
.DS
\f(CWDwarf_Unsigned max = 0;
Dwarf_Off cur_off = 0;
Dwarf_Signed count = 0;
Dwarf_Macro_Details *maclist;
int errv;

/* Loop through all the compilation units macro info.  
   This is not guaranteed to work because DWARF does not
   guarantee every byte in the section is meaningful:
   there can be garbage between the macro info
   for CUs.  But this loop will usually work.
*/
while((errv = dwarf_get_macro_details(dbg, cur_off,max,
     &count,&maclist,&error))== DW_DLV_OK) {
    for (i = 0; i < count; ++i) {
      /* use maclist[i] */
    }
    cur_off = maclist[count-1].dmd_offset + 1;
    dwarf_dealloc(dbg, maclist, DW_DLA_STRING);
}\fP
.DE


.H 2 "Low Level Frame Operations"
These functions provide information about stack frames to be
used to perform stack traces.  The information is an abstraction
of a table with a row per instruction and a column per register
and a column for the canonical frame address (CFA, which corresponds
to the notion of a frame pointer), 
as well as a column for the return address.  
.P
From 1993-2006 the interface we'll here refer to as DWARF2
made the CFA be a column in the matrix, but left
DW_FRAME_UNDEFINED_VAL, and DW_FRAME_SAME_VAL out of the matrix
(giving them high numbers). As of the DWARF3 interfaces
introduced in this document in April 2006, there are *two*
interfaces (the original set and a new set). 
Several frame functions work transparently for either set, we
will focus on the ones that are not equally suitable
now.
.P
The original DWARF2 interface set still exists (dwarf_get_fde_info_for_reg(),
dwarf_get_fde_info_for_cfa_reg(), and dwarf_get_fde_info_for_all_regs())
and works adequately for MIPS/IRIX DWARF2 and ABI/ISA sets
that are sufficiently similar to MIPS.
These functions not a good choice for non-MIPS architectures nor
were they a good design for MIPS either.
It's better to switch entirely to the new functions mentioned
in the next paragraph.
This DWARF2 interface set assumes and uses DW_FRAME_CFA_COL
and that is assumed when libdwarf is configured with --enable-oldframecol .
.P
A new DWARF3 interface set of dwarf_get_fde_info_for_reg3(),
dwarf_get_fde_info_for_cfa_reg3(), dwarf_get_fde_info_for_all_regs3(),
dwarf_set_frame_rule_table_size()
dwarf_set_frame_cfa_value(), 
dwarf_set_frame_same_value(),
dwarf_set_frame_undefined_value(), and
dwarf_set_frame_rule_initial_value() 
is more flexible
and will work for many more architectures.
It is also entirely suitable for use with DWARF2 and DWARF4.
The setting of  the 'frame cfa column number' 
defaults to DW_FRAME_CFA_COL3
and it can be set at runtime with dwarf_set_frame_cfa_value().
.P
Mixing use of the DWARF2 interface set with use
of the new DWARF3 interface set
on a single open Dwarf_Debug instance is a mistake.
Do not do it.
.P
We will pretend, from here on unless otherwise
specified, that 
DW_FRAME_CFA_COL3, DW_FRAME_UNDEFINED_VAL,
and DW_FRAME_SAME_VAL are the synthetic column numbers.
These columns may be user-chosen by calls of
dwarf_set_frame_cfa_value()
dwarf_set_frame_undefined_value(), and
dwarf_set_frame_same_value() respectively.

.P
Each cell in the table contains one of the following:

.AL 
.LI
A register + offset(a)(b)

.LI
A register(c)(d)


.LI
A marker (DW_FRAME_UNDEFINED_VAL) meaning \fIregister value undefined\fP

.LI
A marker (DW_FRAME_SAME_VAL) meaning 
\fIregister value same as in caller\fP
.LE
.P
(a old DWARF2 interface) When  the column is DW_FRAME_CFA_COL: 
the register
number is a real hardware register, not a reference
to DW_FRAME_CFA_COL, not  DW_FRAME_UNDEFINED_VAL,
and not DW_FRAME_SAME_VAL. 
The CFA rule value should be the stack pointer
plus offset 0 when no other value makes sense.
A value of DW_FRAME_SAME_VAL would
be semi-logical, but since the CFA is not a real register,
not really correct.
A value of DW_FRAME_UNDEFINED_VAL would imply
the CFA is undefined  --
this seems to be a useless notion, as
the CFA is a means to finding real registers,
so those real registers should be marked DW_FRAME_UNDEFINED_VAL,
and the CFA column content (whatever register it
specifies) becomes unreferenced by anything.
.P
(a new April 2006 DWARF2/3 interface): The CFA is
separately accessible and not part of the table.
The 'rule number' for the CFA is a number outside the table. 
So the CFA is a marker, not a register number.
See  DW_FRAME_CFA_COL3 in libdwarf.h and
dwarf_get_fde_info_for_cfa_reg3() and
dwarf_set_frame_rule_cfa_value().
.P
(b) When the column is not DW_FRAME_CFA_COL3, the 'register'
will and must be DW_FRAME_CFA_COL3(COL), implying that
to get the final location for the column one must add
the offset here plus the DW_FRAME_CFA_COL3 rule value.
.P
(c) When the column is DW_FRAME_CFA_COL3, then the 'register'
number is (must be) a real hardware register .
(This paragraph does not apply to the April 2006 new interface).
If it were DW_FRAME_UNDEFINED_VAL or DW_FRAME_SAME_VAL
it would be a marker, not a register number.
.P
(d) When the column is not DW_FRAME_CFA_COL3, the register
may be a hardware register.
It will not be DW_FRAME_CFA_COL3.
.P
There is no 'column' for DW_FRAME_UNDEFINED_VAL or DW_FRAME_SAME_VAL.
Nor for DW_FRAME_CFA_COL3.

Figure \n(aX
is machine dependent and represents MIPS CPU register
assignments.  The DW_FRAME_CFA_COL define in dwarf.h
is historical and really belongs
in libdwarf.h, not dwarf.h.
.DS
.TS
center box, tab(:);
lfB lfB lfB
l c l.
NAME:value:PURPOSE
_
DW_FRAME_CFA_COL:0:column used for CFA
DW_FRAME_REG1:1:integer register 1
DW_FRAME_REG2:2:integer register 2
---::obvious names and values here
DW_FRAME_REG30:30:integer register 30 
DW_FRAME_REG31:31:integer register 31
DW_FRAME_FREG0:32:floating point register 0
DW_FRAME_FREG1:33:floating point register 1
---::obvious names and values here
DW_FRAME_FREG30:62:floating point register 30
DW_FRAME_FREG31:63:floating point register 31
DW_FRAME_RA_COL:64:column recording ra
DW_FRAME_UNDEFINED_VAL:1034:register val undefined
DW_FRAME_SAME_VAL:1035:register same as in caller
.TE

.FG "Frame Information Rule Assignments MIPS"
.DE
.P
The following table shows SGI/MIPS specific 
special cell values: these values mean 
that the cell has the value \fIundefined\fP or \fIsame value\fP
respectively, rather than containing a \fIregister\fP or
\fIregister+offset\fP.  
It assumes DW_FRAME_CFA_COL is a table rule, which
is not readily accomplished or even sensible for some architectures.
.P
.DS
.TS
center box, tab(:);
lfB lfB lfB
l c l.
NAME:value:PURPOSE
_
DW_FRAME_UNDEFINED_VAL:1034:means undefined value.
::Not a column or register value
DW_FRAME_SAME_VAL:1035:means 'same value' as
::caller had. Not a column or 
::register value
DW_FRAME_CFA_COL:0:means register zero is
::usurped by the CFA column.
::
.TE
.FG "Frame Information Special Values any architecture"
.DE

.P
The following table shows more general special cell values. 
These values mean
that the cell register-number refers to the \fIcfa-register\fP or 
\fIundefined-value\fP or \fIsame-value\fP
respectively, rather than referring to a \fIregister in the table\fP.
The generality arises from making DW_FRAME_CFA_COL3 be
outside the set of registers and making the cfa rule accessible
from outside the rule-table.
.P
.DS
.TS
center box, tab(:);
lfB lfB lfB
l c l.
NAME:value:PURPOSE
_
DW_FRAME_UNDEFINED_VAL:1034:means undefined value.
::Not a column or register value
DW_FRAME_SAME_VAL:1035:means 'same value' as
::caller had. Not a column or
::register value
DW_FRAME_CFA_COL3:1436:means 'cfa register' is referred to,
::not a real register, not a column, but the cfa (the cfa
::does have a value, but in the DWARF3 libdwarf interface
::it does not have a 'real register number').
.TE
.DE

.P
.H 4 "dwarf_get_fde_list()"
.DS
\f(CWint dwarf_get_fde_list(
        Dwarf_Debug dbg,
        Dwarf_Cie **cie_data,
        Dwarf_Signed *cie_element_count,
        Dwarf_Fde **fde_data,
        Dwarf_Signed *fde_element_count,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_get_fde_list()\fP stores a pointer to a list of 
\f(CWDwarf_Cie\fP descriptors in \f(CW*cie_data\fP, and the 
count of the number of descriptors in \f(CW*cie_element_count\fP.  
There is a descriptor for each CIE in the .debug_frame section.  
Similarly, it stores a pointer to a list of \f(CWDwarf_Fde\fP 
descriptors in \f(CW*fde_data\fP, and the count of the number 
of descriptors in \f(CW*fde_element_count\fP.  There is one 
descriptor per FDE in the .debug_frame section.  
\f(CWdwarf_get_fde_list()\fP  returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if it cannot find frame entries.
It returns \f(CWDW_DLV_OK\fP on a successful return.
.P
On successful return, structures pointed to by a
descriptor should be freed using \f(CWdwarf_fde_cie_list_dealloc()\fP.
This dealloc approach is new as of July 15, 2005.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Cie *cie_data;
Dwarf_Signed cie_count;
Dwarf_Fde *fde_data;
Dwarf_Signed fde_count;
int fres;

fres = dwarf_get_fde_list(dbg,&cie_data,&cie_count,
                &fde_data,&fde_count,&error);
if (fres == DW_DLV_OK) {
        dwarf_fde_cie_list_dealloc(dbg, cie_data, cie_count,
		fde_data,fde_count);
}\fP
.DE
.in -2



.P
The following code is deprecated as of July 15, 2005 as it does not
free all relevant memory.
This approach  still works as well as it ever did.
.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Cie *cie_data;
Dwarf_Signed cie_count;
Dwarf_Fde *fde_data;
Dwarf_Signed fde_count;
int fres;

fres = dwarf_get_fde_list(dbg,&cie_data,&cie_count, 
		&fde_data,&fde_count,&error);
if (fres == DW_DLV_OK) {

        for (i = 0; i < cie_count; ++i) {
                /* use cie[i] */
                dwarf_dealloc(dbg, cie_data[i], DW_DLA_CIE);
        }
        for (i = 0; i < fde_count; ++i) {
                /* use fde[i] */
                dwarf_dealloc(dbg, fde_data[i], DW_DLA_FDE);
        }
        dwarf_dealloc(dbg, cie_data, DW_DLA_LIST);
        dwarf_dealloc(dbg, fde_data, DW_DLA_LIST);
}\fP
.DE
.in -2

.P
.H 4 "dwarf_get_fde_list_eh()"
.DS
\f(CWint dwarf_get_fde_list_eh(
        Dwarf_Debug dbg,
        Dwarf_Cie **cie_data,
        Dwarf_Signed *cie_element_count,
        Dwarf_Fde **fde_data,
        Dwarf_Signed *fde_element_count,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_get_fde_list_eh()\fP is identical to
\f(CWdwarf_get_fde_list()\fP except that
\f(CWdwarf_get_fde_list_eh()\fP reads the GNU gcc
section named .eh_frame (C++ exception handling information).

\f(CWdwarf_get_fde_list_eh()\fP stores a pointer to a list of
\f(CWDwarf_Cie\fP descriptors in \f(CW*cie_data\fP, and the
count of the number of descriptors in \f(CW*cie_element_count\fP.
There is a descriptor for each CIE in the .debug_frame section.
Similarly, it stores a pointer to a list of \f(CWDwarf_Fde\fP
descriptors in \f(CW*fde_data\fP, and the count of the number
of descriptors in \f(CW*fde_element_count\fP.  There is one
descriptor per FDE in the .debug_frame section.
\f(CWdwarf_get_fde_list()\fP  returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if it cannot find 
exception handling entries.
It returns \f(CWDW_DLV_OK\fP on a successful return.

.P
On successful return, structures pointed to by a
descriptor should be freed using \f(CWdwarf_fde_cie_list_dealloc()\fP.
This dealloc approach is new as of July 15, 2005.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Cie *cie_data;
Dwarf_Signed cie_count;
Dwarf_Fde *fde_data;
Dwarf_Signed fde_count;
int fres;

fres = dwarf_get_fde_list(dbg,&cie_data,&cie_count,
                &fde_data,&fde_count,&error);
if (fres == DW_DLV_OK) {
        dwarf_fde_cie_list_dealloc(dbg, cie_data, cie_count,
                fde_data,fde_count);
}\fP
.DE
.in -2


.P
.H 4 "dwarf_get_cie_of_fde()"
.DS
\f(CWint dwarf_get_cie_of_fde(Dwarf_Fde fde,
        Dwarf_Cie *cie_returned,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_get_cie_of_fde()\fP stores a \f(CWDwarf_Cie\fP
into the  \f(CWDwarf_Cie\fP that \f(CWcie_returned\fP points at.

If one has called dwarf_get_fde_list and does not wish
to dwarf_dealloc() all the individual FDEs immediately, one
must also avoid dwarf_dealloc-ing the CIEs for those FDEs
not immediately dealloc'd.
Failing to observe this restriction will cause the  FDE(s) not
dealloc'd to become invalid: an FDE contains (hidden in it)
a CIE pointer which will be be invalid (stale, pointing to freed memory)
if the CIE is dealloc'd.
The invalid CIE pointer internal to the FDE cannot be detected
as invalid by libdwarf.
If one later passes an FDE with a stale internal CIE pointer
to one of the routines taking an FDE as input the result will
be failure of the call (returning DW_DLV_ERROR) at best and
it is possible a coredump or worse will happen (eventually).


\f(CWdwarf_get_cie_of_fde()\fP returns 
\f(CWDW_DLV_OK\fP if it is successful (it will be
unless fde is the NULL pointer).
It returns \f(CWDW_DLV_ERROR\fP if the fde is invalid (NULL).

.P
Each \f(CWDwarf_Fde\fP descriptor describes information about the
frame for a particular subroutine or function.

\f(CWint dwarf_get_fde_for_die\fP is SGI/MIPS specific.

.H 4 "dwarf_get_fde_for_die()"
.DS
\f(CWint dwarf_get_fde_for_die(
        Dwarf_Debug dbg,
        Dwarf_Die die,
        Dwarf_Fde *  return_fde,
        Dwarf_Error *error)\fP
.DE
When it succeeds,
\f(CWdwarf_get_fde_for_die()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*return_fde\fP
to
a \f(CWDwarf_Fde\fP
descriptor representing frame information for the given \f(CWdie\fP.  It 
looks for the \f(CWDW_AT_MIPS_fde\fP attribute in the given \f(CWdie\fP.
If it finds it, is uses the value of the attribute as the offset in 
the .debug_frame section where the FDE begins.
If there is no \f(CWDW_AT_MIPS_fde\fP it returns \f(CWDW_DLV_NO_ENTRY\fP.
If there is an error it returns \f(CWDW_DLV_ERROR\fP.

.H 4 "dwarf_get_fde_range()"
.DS
\f(CWint dwarf_get_fde_range(
        Dwarf_Fde fde,
        Dwarf_Addr *low_pc,
        Dwarf_Unsigned *func_length,
        Dwarf_Ptr *fde_bytes,
        Dwarf_Unsigned *fde_byte_length,
        Dwarf_Off *cie_offset,
        Dwarf_Signed *cie_index,
        Dwarf_Off *fde_offset,
        Dwarf_Error *error);\fP
.DE
On success,
\f(CWdwarf_get_fde_range()\fP returns
\f(CWDW_DLV_OK\fP.

The location pointed to by \f(CWlow_pc\fP is set to the low pc value for
this function.  

The location pointed to by \f(CWfunc_length\fP is 
set to the length of the function in bytes.  
This is essentially the
length of the text section for the function.  

The location pointed
to by \f(CWfde_bytes\fP is set to the address where the FDE begins
in the .debug_frame section.  

The location pointed to by 
\f(CWfde_byte_length\fP is set to the length in bytes of the portion
of .debug_frame for this FDE.  
This is the same as the value returned
by \f(CWdwarf_get_fde_range\fP.  

The location pointed to by 
\f(CWcie_offset\fP is set to the offset in the .debug_frame section
of the CIE used by this FDE.  

The location pointed to by \f(CWcie_index\fP
is set to the index of the CIE used by this FDE.  
The index is the 
index of the CIE in the list pointed to by \f(CWcie_data\fP as set 
by the function \f(CWdwarf_get_fde_list()\fP.  
However, if the function
\f(CWdwarf_get_fde_for_die()\fP was used to obtain the given \f(CWfde\fP, 
this index may not be correct.   

The location pointed to by 
\f(CWfde_offset\fP is set to the offset of the start of this FDE in 
the .debug_frame section.  

\f(CWdwarf_get_fde_range()\fP returns \f(CWDW_DLV_ERROR\fP on error.

.H 4 "dwarf_get_cie_info()"
.DS
\f(CWint dwarf_get_cie_info(
        Dwarf_Cie       cie,
	Dwarf_Unsigned *bytes_in_cie,
        Dwarf_Small    *version,
        char          **augmenter,
        Dwarf_Unsigned *code_alignment_factor,
        Dwarf_Signed *data_alignment_factor,
        Dwarf_Half     *return_address_register_rule,
        Dwarf_Ptr      *initial_instructions,
        Dwarf_Unsigned *initial_instructions_length,
        Dwarf_Error    *error);\fP
.DE
\f(CWdwarf_get_cie_info()\fP is primarily for Internal-level Interface 
consumers.  
If successful,
it returns
\f(CWDW_DLV_OK\fP and sets \f(CW*bytes_in_cie\fP to
the number of bytes in the portion of the
frames section for the CIE represented by the given \f(CWDwarf_Cie\fP
descriptor, \f(CWcie\fP.  
The other fields are directly taken from 
the cie and returned, via the pointers to the caller.  
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 4 "dwarf_get_cie_index()"
.DS
\f(CWint dwarf_get_cie_index(
        Dwarf_Cie cie,
        Dwarf_Signed *cie_index,
        Dwarf_Error *error);\fP
.DE
On success,
\f(CWdwarf_get_cie_index()\fP returns
\f(CWDW_DLV_OK\fP.
On error this function returns \f(CWDW_DLV_ERROR\fP.

The location pointed to by \f(CWcie_index\fP
is set to the index of the CIE of this FDE.
The index is the
index of the CIE in the list pointed to by \f(CWcie_data\fP as set
by the function \f(CWdwarf_get_fde_list()\fP.

So one must have used \f(CWdwarf_get_fde_list()\fP or
\f(CWdwarf_get_fde_list_eh()\fP to get
a cie list before this is meaningful.

This function is occasionally useful, but is
little used.

.H 4 "dwarf_get_fde_instr_bytes()"
.DS
\f(CWint dwarf_get_fde_instr_bytes(
        Dwarf_Fde fde,
	Dwarf_Ptr *outinstrs,
	Dwarf_Unsigned *outlen,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_get_fde_instr_bytes()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*outinstrs\fP to
a pointer to a set of bytes which are the
actual frame instructions for this fde.
It also sets \f(CW*outlen\fP to the length, in
bytes, of the frame instructions.
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
The intent is to allow low-level consumers like a dwarf-dumper
to print the bytes in some fashion.
The memory pointed to by \f(CWoutinstrs\fP
must not be changed and there
is nothing to free.

.H 4 "dwarf_get_fde_info_for_reg()"
This interface is suitable for DWARF2 but is not
sufficient for DWARF3.  See \f(CWint dwarf_get_fde_info_for_reg3\fP.
.DS
\f(CWint dwarf_get_fde_info_for_reg(
        Dwarf_Fde fde,
        Dwarf_Half table_column,
        Dwarf_Addr pc_requested,
	Dwarf_Signed *offset_relevant,
        Dwarf_Signed *register_num,
        Dwarf_Signed *offset,
        Dwarf_Addr *row_pc,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_get_fde_info_for_reg()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*offset_relevant\fP to
non-zero if the offset is relevant for the
row specified by \f(CWpc_requested\fP and column specified by
\f(CWtable_column\fP, for the FDE specified by \f(CWfde\fP.  
The
intent is to return the rule for the given pc value and register.
The location pointed to by \f(CWregister_num\fP is set to the register
value for the rule.  
The location pointed to by \f(CWoffset\fP 
is set to the offset value for the rule.  
If offset is not relevant for this rule, \f(CW*offset_relevant\fP is
set to zero.
Since more than one pc 
value will have rows with identical entries, the user may want to
know the earliest pc value after which the rules for all the columns
remained unchanged.  
Recall that in the virtual table that the frame information
represents there may be one or more table rows with identical data
(each such table row at a different pc value).
Given a \f(CWpc_requested\fP which refers to a pc in such a group
of identical rows, 
the location pointed to by \f(CWrow_pc\fP is set 
to the lowest pc value
within the group of  identical rows.
The  value put in \f(CW*register_num\fP any of the
\f(CWDW_FRAME_*\fP table columns values specified in \f(CWlibdwarf.h\fP
or \f(CWdwarf.h\fP.

\f(CWdwarf_get_fde_info_for_reg\fP returns \f(CWDW_DLV_ERROR\fP if there is an error. 

It is usable with either 
\f(CWdwarf_get_fde_n()\fP or \f(CWdwarf_get_fde_at_pc()\fP.

\f(CWdwarf_get_fde_info_for_reg()\fP is tailored to MIPS, please use
\f(CWdwarf_get_fde_info_for_reg3()\fP instead for all architectures.


.H 4 "dwarf_get_fde_info_for_all_regs()"
.DS
\f(CWint dwarf_get_fde_info_for_all_regs(
        Dwarf_Fde fde,
        Dwarf_Addr pc_requested,
	Dwarf_Regtable *reg_table,
        Dwarf_Addr *row_pc,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_get_fde_info_for_all_regs()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*reg_table\fP for the row specified by
\f(CWpc_requested\fP for the FDE specified by \f(CWfde\fP. 
.P
The intent is
to return the rules for decoding all the registers, given a pc value.
\f(CWreg_table\fP is an array of rules, one for each register specified in
\f(CWdwarf.h\fP. The rule for each register contains three items - 
\f(CWdw_regnum\fP which denotes the register value for that rule,
\f(CWdw_offset\fP which denotes the offset value for that rule and 
\f(CWdw_offset_relevant\fP which is set to zero if offset is not relevant 
for that rule. See \f(CWdwarf_get_fde_info_for_reg()\fP for a description 
of \f(CWrow_pc\fP.
.P
\f(CWdwarf_get_fde_info_for_all_regs\fP returns \f(CWDW_DLV_ERROR\fP if there is an error. 
.P
\f(CWint dwarf_get_fde_info_for_all_regs\fP is tailored to SGI/MIPS,
please use dwarf_get_fde_info_for_all_regs3() instead for all architectures.


.H 4 "dwarf_set_frame_rule_table_size()"
.P
This allows consumers to set the size of the (internal to libdwarf)
rule table when using the 'reg3' interfaces (these interfaces
are strongly preferred over the older 'reg' interfaces).  
It should be at least as large as the
number of real registers in the ABI which is to be read in
for the dwarf_get_fde_info_for_reg3() or dwarf_get_fde_info_for_all_regs3()
functions to work properly.

The frame rule table size must be less than the marker values
DW_FRAME_UNDEFINED_VAL, DW_FRAME_SAME_VAL, DW_FRAME_CFA_COL3
(dwarf_set_frame_rule_undefined_value()
dwarf_set_frame_same_value()
dwarf_set_frame_cfa_value()
effectively set these markers so
the frame rule table size can actually be any value regardless
of the macro values in libdwarf.h as long as the table size
does not overlap these markers).
.P
.DS
\f(CWDwarf_Half
dwarf_set_frame_rule_table_size(Dwarf_Debug dbg,
         Dwarf_Half value);\fP

.DE
\f(CWdwarf_set_frame_rule_table_size()\fP sets the
value \f(CWvalue\fP as the size of libdwarf-internal
rules tables  of \f(CWdbg\fP.
.P
The function returns
the previous value of the rules table size setting (taken from the 
\f(CWdbg\fP structure).

.H 4 "dwarf_set_frame_rule_initial_value()"
This allows consumers to set the initial value
for rows in the frame tables.  By default it
is taken from libdwarf.h and is DW_FRAME_REG_INITIAL_VALUE
(which itself is either DW_FRAME_SAME_VAL or DW_FRAME_UNDEFINED_VAL).
The MIPS/IRIX default is DW_FRAME_SAME_VAL.
Consumer code should set this appropriately and for
many architectures (but probably not MIPS) DW_FRAME_UNDEFINED_VAL is an
appropriate setting.
Note: an earlier spelling of dwarf_set_frame_rule_inital_value()
is still supported as an interface, but please change to use
the new correctly spelled name.
.DS
\f(CWDwarf_Half
dwarf_set_frame_rule_initial_value(Dwarf_Debug dbg,
         Dwarf_Half value);\fP

.DE
\f(CWdwarf_set_frame_rule_initial_value()\fP sets the
value \f(CWvalue\fP as the initial value for this \f(CWdbg\fP
when initializing rules tables.  
.P
The function returns
the previous value of initial value (taken from the 
\f(CWdbg\fP structure).

.H 4 "dwarf_set_frame_cfa_value()"
This allows consumers to set the number of the CFA register
for rows in the frame tables.  By default it
is taken from libdwarf.h and is \f(CWDW_FRAME_CFA_COL\fP.
Consumer code should set this appropriately and for
nearly all architectures \f(CWDW_FRAME_CFA_COL3\fP is an
appropriate setting.
.DS
\f(CWDwarf_Half
dwarf_set_frame_rule_cfa_value(Dwarf_Debug dbg,
         Dwarf_Half value);\fP

.DE
\f(CWdwarf_set_frame_rule_cfa_value()\fP sets the
value \f(CWvalue\fP as the  number of the cfa 'register rule'
for this \f(CWdbg\fP
when initializing rules tables.  
.P
The function returns
the previous value of the pseudo-register (taken from the
\f(CWdbg\fP structure).

.H 4 "dwarf_set_frame_same_value()"
This allows consumers to set the number of the pseudo-register
when DW_CFA_same_value is the operation.  By default it
is taken from libdwarf.h and is \f(CWDW_FRAME_SAME_VAL\fP.
Consumer code should set this appropriately, though for
many architectures \f(CWDW_FRAME_SAME_VAL\fP is an
appropriate setting.
.DS
\f(CWDwarf_Half
dwarf_set_frame_rule_same_value(Dwarf_Debug dbg,
         Dwarf_Half value);\fP

.DE
\f(CWdwarf_set_frame_rule_same_value()\fP sets the
value \f(CWvalue\fP as the  number of the register
that is the pseudo-register set by the DW_CFA_same_value
frame operation.
.P
The function returns
the previous value of the pseudo-register  (taken from the
\f(CWdbg\fP structure).


.H 4 "dwarf_set_frame_undefined_value()"
This allows consumers to set the number of the pseudo-register
 when DW_CFA_undefined_value is the operation.  By default it
is taken from libdwarf.h and is \f(CWDW_FRAME_UNDEFINED_VAL\fP.
Consumer code should set this appropriately, though for
many architectures \f(CWDW_FRAME_UNDEFINED_VAL\fP is an
appropriate setting.
.DS
\f(CWDwarf_Half
dwarf_set_frame_rule_undefined_value(Dwarf_Debug dbg,
         Dwarf_Half value);\fP

.DE
\f(CWdwarf_set_frame_rule_undefined_value()\fP sets the
value \f(CWvalue\fP as the  number of the register
that is the pseudo-register set by the DW_CFA_undefined_value
frame operation.
.P
The function returns
the previous value of the pseudo-register  (taken from the
\f(CWdbg\fP structure).

.H 4 "dwarf_set_default_address_size()"
This allows consumers to set a default address size.
When one has an object where the
default address_size does not match the frame address
size where there is no debug_info available to get a
frame-specific address-size, this function is useful.
For example, if an Elf64 object has a .debug_frame whose
real address_size is 4 (32 bits).  This a very rare
situation.
.DS
\f(CWDwarf_Small
dwarf_set_default_address_size(Dwarf_Debug dbg,
         Dwarf_Small value);\fP

.DE
\f(CWdwarf_set_default_address_size()\fP sets the
value \f(CWvalue\fP as the  default address size for
this activation of the reader, but only if \f(CWvalue\fP
is greater than zero (otherwise the default address size
is not changed).
.P
The function returns
the previous value of the default address size  (taken from the
\f(CWdbg\fP structure).



.H 4 "dwarf_get_fde_info_for_reg3()"
This interface is suitable for DWARF3 and DWARF2.
It returns the values for a particular real register
(Not for the CFA register, see dwarf_get_fde_info_for_cfa_reg3()
below).
If the application is going to retrieve the value for more
than a few \f(CWtable_column\fP values at this \f(CWpc_requested\fP
(by calling this function multiple times)
it is much more efficient to
call dwarf_get_fde_info_for_all_regs3() (in spite
of the additional setup that requires of the caller).

.DS
\f(CWint dwarf_get_fde_info_for_reg3(
        Dwarf_Fde fde,
        Dwarf_Half table_column,
        Dwarf_Addr pc_requested,
	Dwarf_Small  *value_type,
	Dwarf_Signed *offset_relevant,
        Dwarf_Signed *register_num,
        Dwarf_Signed *offset_or_block_len,
	Dwarf_Ptr    *block_ptr,
        Dwarf_Addr   *row_pc,
        Dwarf_Error  *error);\fP
.DE
\f(CWdwarf_get_fde_info_for_reg3()\fP returns
\f(CWDW_DLV_OK\fP on success. 
It sets \f(CW*value_type\fP
to one of  DW_EXPR_OFFSET (0),
DW_EXPR_VAL_OFFSET(1), DW_EXPR_EXPRESSION(2) or
DW_EXPR_VAL_EXPRESSION(3).
On call, \f(CWtable_column\fP must be set to the
register number of a real register. Not
the cfa 'register' or DW_FRAME_SAME_VALUE or
DW_FRAME_UNDEFINED_VALUE.


if \f(CW*value_type\fP has the value DW_EXPR_OFFSET (0) then:
.in +4
.P
It sets \f(CW*offset_relevant\fP to
non-zero if the offset is relevant for the
row specified by \f(CWpc_requested\fP and column specified by
\f(CWtable_column\fP or, for the FDE specified by \f(CWfde\fP.  
In this case  the  \f(CW*register_num\fP will be set
to DW_FRAME_CFA_COL3 (.  This is an offset(N) rule
as specified in the DWARF3/2 documents.
Adding the value of \f(CW*offset_or_block_len\fP
to the value of the CFA register gives the address
of a location holding the previous value of 
register \f(CWtable_column\fP.

.P
If offset is not relevant for this rule, \f(CW*offset_relevant\fP is
set to zero.  \f(CW*register_num\fP will be set
to the number of the real register holding the value of 
the \f(CWtable_column\fP register.
This is the register(R) rule as specified in DWARF3/2 documents.
.P
The
intent is to return the rule for the given pc value and register.
The location pointed to by \f(CWregister_num\fP is set to the register
value for the rule.  
The location pointed to by \f(CWoffset\fP 
is set to the offset value for the rule.  
Since more than one pc 
value will have rows with identical entries, the user may want to
know the earliest pc value after which the rules for all the columns
remained unchanged.  
Recall that in the virtual table that the frame information
represents there may be one or more table rows with identical data
(each such table row at a different pc value).
Given a \f(CWpc_requested\fP which refers to a pc in such a group
of identical rows, 
the location pointed to by \f(CWrow_pc\fP is set 
to the lowest pc value
within the group of  identical rows.

.in -4

.P
If \f(CW*value_type\fP has the value DW_EXPR_VAL_OFFSET (1) then:
.in +4
This will be a val_offset(N) rule as specified in the
DWARF3/2 documents so  \f(CW*offset_relevant\fP will
be non zero. 
The calculation is identical to the  DW_EXPR_OFFSET (0)
calculation with  \f(CW*offset_relevant\fP non-zero, 
but the value  resulting is the actual \f(CWtable_column\fP
value (rather than the address where the value may be found).
.in -4
.P
If \f(CW*value_type\fP has the value DW_EXPR_EXPRESSION (1) then:
.in +4
 \f(CW*offset_or_block_len\fP
is set to the length in bytes of a block of memory
with a DWARF expression in the block.
\f(CW*block_ptr\fP is set to point at the block of memory.
The consumer code should  evaluate the block as
a DWARF-expression. The result is the address where
the previous value of the register may be found.
This is a DWARF3/2 expression(E) rule.
.in -4
.P
If \f(CW*value_type\fP has the value DW_EXPR_VAL_EXPRESSION (1) then:
.in +4
The calculation is exactly as for DW_EXPR_EXPRESSION (1)
but the result of the DWARF-expression evaluation is
the value of the   \f(CWtable_column\fP (not
the address of the value).
This is a DWARF3/2 val_expression(E) rule.
.in -4

\f(CWdwarf_get_fde_info_for_reg\fP 
returns \f(CWDW_DLV_ERROR\fP if there is an error and
if there is an error only the \f(CWerror\fP pointer is set, none
of the other output arguments are touched.

It is usable with either 
\f(CWdwarf_get_fde_n()\fP or \f(CWdwarf_get_fde_at_pc()\fP.


.H 4 "dwarf_get_fde_info_for_cfa_reg3()"
.DS
 \f(CWint dwarf_get_fde_info_for_cfa_reg3(Dwarf_Fde fde,
      Dwarf_Addr          pc_requested,
      Dwarf_Small *       value_type,
      Dwarf_Signed*       offset_relevant,
      Dwarf_Signed*       register_num,
      Dwarf_Signed*       offset_or_block_len,
      Dwarf_Ptr   *       block_ptr ,
      Dwarf_Addr  *       row_pc_out,
      Dwarf_Error *       error)\fP
.DE
.P
This is identical to  \f(CWdwarf_get_fde_info_for_reg3()\fP
except the returned values are for the CFA rule.
So register number \f(CW*register_num\fP will be set
to a real register, not one of the pseudo registers
(which are usually
DW_FRAME_CFA_COL3, DW_FRAME_SAME_VALUE, or
DW_FRAME_UNDEFINED_VALUE).



.H 4 "dwarf_get_fde_info_for_all_regs3()"
.DS
\f(CWint dwarf_get_fde_info_for_all_regs3(
        Dwarf_Fde fde,
        Dwarf_Addr pc_requested,
	Dwarf_Regtable3 *reg_table,
        Dwarf_Addr *row_pc,
        Dwarf_Error *error)\fP
.DE
\f(CWdwarf_get_fde_info_for_all_regs3()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*reg_table\fP 
for the row specified by
\f(CWpc_requested\fP for the FDE specified by \f(CWfde\fP. 
The intent is
to return the rules for decoding all the registers, given a pc
value.  
\f(CWreg_table\fP is an array of rules, the 
array size specified by the caller.
plus a rule for the CFA.
The rule for the cfa returned in  \f(CW*reg_table\fP
defines the CFA value at  \f(CWpc_requested\fP
The rule for each
register contains  several values that enable
the consumer to determine the previous value
of the register (see the earlier documentation of Dwarf_Regtable3).
\f(CWdwarf_get_fde_info_for_reg3()\fP  and
the Dwarf_Regtable3 documentation above for a description of
the values for each row.

\f(CWdwarf_get_fde_info_for_all_regs3\fP returns \f(CWDW_DLV_ERROR\fP if there is an error. 

It is up to the caller to allocate space for 
\f(CW*reg_table\fP and initialize it properly.



.H 4 "dwarf_get_fde_n()"
.DS
\f(CWint   dwarf_get_fde_n(
        Dwarf_Fde *fde_data,
        Dwarf_Unsigned fde_index,
	Dwarf_Fde      *returned_fde
        Dwarf_Error *error)\fP
.DE
\f(CWdwarf_get_fde_n()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CWreturned_fde\fP to
the \f(CWDwarf_Fde\fP descriptor whose 
index is \f(CWfde_index\fP in the table of \f(CWDwarf_Fde\fP descriptors
pointed to by \fPfde_data\fP.  
The index starts with 0.  
The table pointed to by fde_data is required to contain
at least one entry. If the table has no entries at all
the error checks may refer to uninitialized memory.
Returns \f(CWDW_DLV_NO_ENTRY\fP if the index does not 
exist in the table of \f(CWDwarf_Fde\fP 
descriptors. 
Returns \f(CWDW_DLV_ERROR\fP if there is an error.
This function cannot be used unless
the block of \f(CWDwarf_Fde\fP descriptors has been created by a call to
\f(CWdwarf_get_fde_list()\fP.

.H 4 "dwarf_get_fde_at_pc()"
.DS
\f(CWint   dwarf_get_fde_at_pc(
        Dwarf_Fde *fde_data,
        Dwarf_Addr pc_of_interest,
        Dwarf_Fde *returned_fde,
        Dwarf_Addr *lopc,
        Dwarf_Addr *hipc,
        Dwarf_Error *error)\fP
.DE
\f(CWdwarf_get_fde_at_pc()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CWreturned_fde\fP to
a \f(CWDwarf_Fde\fP descriptor
for a function which contains the pc value specified by \f(CWpc_of_interest\fP.
In addition, it sets the locations pointed to 
by \f(CWlopc\fP and \f(CWhipc\fP to the low address and the high address 
covered by this FDE, respectively.  
The table pointed to by fde_data is required to contain
at least one entry. If the table has no entries at all
the error checks may refer to uninitialized memory.
It returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP 
if \f(CWpc_of_interest\fP is not in any of the
FDEs represented by the block of \f(CWDwarf_Fde\fP descriptors pointed
to by \f(CWfde_data\fP.  
This function cannot be used unless
the block of \f(CWDwarf_Fde\fP descriptors has been created by a call to
\f(CWdwarf_get_fde_list()\fP.

.H 4 "dwarf_expand_frame_instructions()"
.DS
\f(CWint dwarf_expand_frame_instructions(
        Dwarf_Cie cie,
        Dwarf_Ptr instruction,
        Dwarf_Unsigned i_length,
        Dwarf_Frame_Op **returned_op_list,
        Dwarf_Signed   * returned_op_count,
        Dwarf_Error *error);\fP
.DE
\f(CWdwarf_expand_frame_instructions()\fP is a High-level interface 
function which expands a frame instruction byte stream into an 
array of \f(CWDwarf_Frame_Op\fP structures.  
To indicate success, it returns \f(CWDW_DLV_OK\fP.
The address where 
the byte stream begins is specified by \f(CWinstruction\fP, and
the length of the byte stream is specified by \f(CWi_length\fP.
The location pointed to by \f(CWreturned_op_list\fP is set to
point to a table of 
\f(CWreturned_op_count\fP
pointers to \f(CWDwarf_Frame_Op\fP which
contain the frame instructions in the byte stream.  
It returns \f(CWDW_DLV_ERROR\fP on error. 
It never returns \f(CWDW_DLV_NO_ENTRY\fP.
After a successful return, the
array of structures should be freed using
\f(CWdwarf_dealloc()\fP with the allocation type \f(CWDW_DLA_FRAME_BLOCK\fP
(when they are no longer of interest).
.P
Not all CIEs have the same address-size, so it is crucial
that a CIE pointer to the frame's CIE be passed in.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Frame_Op *frameops;
Dwarf_Ptr instruction;
Dwarf_Unsigned len;
int res;

res = expand_frame_instructions(dbg,instruction,len, &frameops,&cnt, &error);
if (res == DW_DLV_OK) {
    for (i = 0; i < cnt; ++i) {
        /* use frameops[i] */
    }
    dwarf_dealloc(dbg, frameops, DW_DLA_FRAME_BLOCK);
}\fP
.DE
.in -2
.H 4 "dwarf_get_fde_exception_info()"
.DS
\f(CWint dwarf_get_fde_exception_info(
    Dwarf_Fde fde,
    Dwarf_Signed * offset_into_exception_tables,
    Dwarf_Error * error);
.DE
\f(CWdwarf_get_fde_exception_info()\fP is an IRIX specific
function which returns an exception table signed offset
through \f(CWoffset_into_exception_tables\fP.
The function never returns \f(CWDW_DLV_NO_ENTRY\fP.
If \f(CWDW_DLV_NO_ENTRY\fP is NULL the function returns 
\f(CWDW_DLV_ERROR\fP.
For non-IRIX objects the offset returned will always be zero.
For non-C++ objects the offset returned will always be zero.
The meaning of the offset and the content of the tables
is not defined in this document.
The applicable CIE augmentation string (see above)
determines whether the value returned has meaning.

.H 2 "Location Expression Evaluation"

An "interpreter" which evaluates a location expression
is required in any debugger.  There is no interface defined
here at this time.  

.P
One problem with defining an interface is that operations are
machine dependent: they depend on the interpretation of
register numbers and the methods of getting values from the
environment the expression is applied to.

.P
It would be desirable to specify an interface.

.H 3 "Location List Internal-level Interface"

.H 4 "dwarf_get_loclist_entry()"
.DS
\f(CWint dwarf_get_loclist_entry(
        Dwarf_Debug dbg,
        Dwarf_Unsigned offset,
        Dwarf_Addr *hipc_offset,
        Dwarf_Addr *lopc_offset,
        Dwarf_Ptr *data,
        Dwarf_Unsigned *entry_len,
        Dwarf_Unsigned *next_entry,
        Dwarf_Error *error)\fP
.DE
The function reads 
a location list entry starting at \f(CWoffset\fP and returns 
through pointers (when successful)
the high pc \f(CWhipc_offset\fP, low pc 
\f(CWlopc_offset\fP, a pointer to the location description data 
\f(CWdata\fP, the length of the location description data 
\f(CWentry_len\fP, and the offset of the next location description 
entry \f(CWnext_entry\fP.  
.P
This function will usually work correctly (meaning with most
objects) but will not work correctly (and can crash
an application calling it) if either
some location list applies to a compilation unit with
an address_size different from the overall address_size
of the object file being read or if the .debug_loc section
being read has random padding bytes between loclists.
Neither of these characteristics necessarily represents
a bug in the compiler/linker toolset that produced the 
object file being read.  The DWARF standard
allows both characteristics.
.P
\f(CWdwarf_dwarf_get_loclist_entry()\fP returns 
\f(CWDW_DLV_OK\fP if successful.
\f(CWDW_DLV_NO_ENTRY\fP is returned when the offset passed
in is beyond the end of the .debug_loc section (expected if
you start at offset zero and proceed through all the entries). 
\f(CWDW_DLV_ERROR\fP is returned on error. 
.P
The \f(CWhipc_offset\fP,
low pc \f(CWlopc_offset\fP are offsets from the beginning of the
current procedure, not genuine pc values.
.in +2
.DS
\f(CW
/* Looping through the dwarf_loc section finding loclists:
   an example.  */
int res;
Dwarf_Unsigned next_entry;
Dwarf_unsigned offset=0;
Dwarf_Addr hipc_off;
Dwarf_Addr lopc_off;
Dwarf_Ptr data;
Dwarf_Unsigned entry_len;
Dwarf_Unsigned next_entry;
Dwarf_Error err;

    for(;;) {      
        res = dwarf_get_loclist_entry(dbg,newoffset,&hipc_off,
            &lowpc_off, &data, &entry_len,&next_entry,&err);
        if (res == DW_DLV_OK) {
            /* A valid entry. */
            newoffset = next_entry;
            continue;
        } else if (res ==DW_DLV_NO_ENTRY) {
            /* Done! */
            break;
        } else {
            /* Error! */
            break;
        }
         

    }
}\fP
.DE
.in -2


.H 2 "Abbreviations access"
These are Internal-level Interface functions.  
Debuggers can ignore this.

.H 3 "dwarf_get_abbrev()"
.DS
\f(CWint dwarf_get_abbrev(
        Dwarf_Debug dbg,
        Dwarf_Unsigned offset,
        Dwarf_Abbrev   *returned_abbrev,
        Dwarf_Unsigned *length,
        Dwarf_Unsigned *attr_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_abbrev()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_abbrev\fP to
\f(CWDwarf_Abbrev\fP 
descriptor for an abbreviation at offset \f(CW*offset\fP in the abbreviations 
section (i.e .debug_abbrev) on success.  
The user is responsible for making sure that 
a valid abbreviation begins at \f(CWoffset\fP in the abbreviations section.  
The location pointed to by \f(CWlength\fP 
is set to the length in bytes of the abbreviation in the abbreviations 
section.  
The location pointed to by \f(CWattr_count\fP is set to the 
number of attributes in the abbreviation.  
An abbreviation entry with a 
length of 1 is the 0 byte of the last abbreviation entry of a compilation 
unit.
\f(CWdwarf_get_abbrev()\fP returns \f(CWDW_DLV_ERROR\fP on error.  
If the call succeeds, the storage pointed to
by \f(CW*returned_abbrev\fP
should be freed, using \f(CWdwarf_dealloc()\fP with the
allocation type \f(CWDW_DLA_ABBREV\fP when no longer needed.


.H 3 "dwarf_get_abbrev_tag()"
.DS
\f(CWint dwarf_get_abbrev_tag(
        Dwarf_abbrev abbrev,
	Dwarf_Half  *return_tag,
        Dwarf_Error *error);\fP
.DE
If successful,
\f(CWdwarf_get_abbrev_tag()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_tag\fP to
the \fItag\fP of 
the given abbreviation.
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 3 "dwarf_get_abbrev_code()"
.DS
\f(CWint dwarf_get_abbrev_code(
        Dwarf_abbrev     abbrev,
	Dwarf_Unsigned  *return_code,
        Dwarf_Error     *error);\fP
.DE
If successful,
\f(CWdwarf_get_abbrev_code()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*return_code\fP to
the abbreviation code of
the given abbreviation.
It returns \f(CWDW_DLV_ERROR\fP on error.
It never returns \f(CWDW_DLV_NO_ENTRY\fP.

.H 3 "dwarf_get_abbrev_children_flag()"
.DS
\f(CWint dwarf_get_abbrev_children_flag(
        Dwarf_Abbrev abbrev,
	Dwarf_Signed  *returned_flag,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_abbrev_children_flag()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CWreturned_flag\fP to
\f(CWDW_children_no\fP (if the given abbreviation indicates that 
a die with that abbreviation has no children) or 
\f(CWDW_children_yes\fP (if the given abbreviation indicates that 
a die with that abbreviation has a child).  
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 3 "dwarf_get_abbrev_entry()"
.DS
\f(CWint dwarf_get_abbrev_entry(
        Dwarf_Abbrev abbrev,
        Dwarf_Signed index,
        Dwarf_Half   *attr_num,
        Dwarf_Signed *form,
        Dwarf_Off *offset,
        Dwarf_Error *error)\fP

.DE
If successful,
\f(CWdwarf_get_abbrev_entry()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*attr_num\fP to the attribute code of
the attribute 
whose index is specified by \f(CWindex\fP in the given abbreviation.  
The index starts at 0.  
The location pointed to by \f(CWform\fP is set 
to the form of the attribute.  
The location pointed to by \f(CWoffset\fP 
is set to the byte offset of the attribute in the abbreviations section.  
It returns \f(CWDW_DLV_NO_ENTRY\fP if the index specified is outside
the range of attributes in this abbreviation.
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 2 "String Section Operations"
The .debug_str section contains only strings.  Debuggers need 
never use this interface: it is only for debugging problems with 
the string section itself.  

.H 3 "dwarf_get_str()"
.DS
\f(CWint dwarf_get_str(
        Dwarf_Debug   dbg,
        Dwarf_Off     offset,
        char        **string,
	Dwarf_Signed *returned_str_len,
        Dwarf_Error  *error)\fP
.DE
The function \f(CWdwarf_get_str()\fP returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_str_len\fP to
the length of 
the string, not counting the null terminator, that begins at the offset 
specified by \f(CWoffset\fP in the .debug_str section.  
The location 
pointed to by \f(CWstring\fP is set to a pointer to this string.
The next string in the .debug_str
section begins at the previous \f(CWoffset\fP + 1 + \f(CW*returned_str_len\fP.
A zero-length string is NOT the end of the section.
If there is no .debug_str section, \f(CWDW_DLV_NO_ENTRY\fP is returned.
If there is an error, \f(CWDW_DLV_ERROR\fP is returned.
If we are at the end of the section (that is, \f(CWoffset\fP
is one past the end of the section) \f(CWDW_DLV_NO_ENTRY\fP is returned.
If the \f(CWoffset\fP is some other too-large value then
\f(CWDW_DLV_ERROR\fP is returned.

.H 2 "Address Range Operations"
These functions provide information about address ranges.  Address
ranges map ranges of pc values to the corresponding compilation-unit
die that covers the address range.

.H 3 "dwarf_get_aranges()"
.DS
\f(CWint dwarf_get_aranges(
        Dwarf_Debug dbg,
        Dwarf_Arange **aranges,
        Dwarf_Signed * returned_arange_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_aranges()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_arange_count\fP to
the count of the
number of address ranges in the .debug_aranges section
(for all compilation units).  
It sets
\f(CW*aranges\fP to point to a block of \f(CWDwarf_Arange\fP 
descriptors, one for each address range.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if there is no .debug_aranges
section.

.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Arange *arang;
int res;

res = dwarf_get_aranges(dbg, &arang,&cnt, &error);
if (res == DW_DLV_OK) {

        for (i = 0; i < cnt; ++i) {
                /* use arang[i] */
                dwarf_dealloc(dbg, arang[i], DW_DLA_ARANGE);
        }
        dwarf_dealloc(dbg, arang, DW_DLA_LIST);
}\fP
.DE
.in -2

.H 3 "dwarf_get_arange()"
.DS
\f(CWint dwarf_get_arange(
        Dwarf_Arange *aranges,
        Dwarf_Unsigned arange_count,
        Dwarf_Addr address,
	Dwarf_Arange *returned_arange,
        Dwarf_Error *error);\fP
.DE
The function \f(CWdwarf_get_arange()\fP takes as input a pointer 
to a block of \f(CWDwarf_Arange\fP pointers, and a count of the
number of descriptors in the block.  
It then searches for the
descriptor that covers the given \f(CWaddress\fP.  
If it finds
one, it returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_arange\fP to
the descriptor. 
It returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if there is no .debug_aranges
entry covering that address.





.H 3 "dwarf_get_cu_die_offset()"
.DS
\f(CWint dwarf_get_cu_die_offset(
        Dwarf_Arange arange,
        Dwarf_Off   *returned_cu_die_offset,
        Dwarf_Error *error);\fP
.DE
The function \f(CWdwarf_get_cu_die_offset()\fP takes a
\f(CWDwarf_Arange\fP descriptor as input, and 
if successful returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_cu_die_offset\fP to
the offset
in the .debug_info section of the compilation-unit DIE for the 
compilation-unit represented by the given address range.
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 3 "dwarf_get_arange_cu_header_offset()"
.DS
\f(CWint dwarf_get_arange_cu_header_offset(
        Dwarf_Arange arange,
        Dwarf_Off   *returned_cu_header_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_arange_cu_header_offset()\fP takes a
\f(CWDwarf_Arange\fP descriptor as input, and 
if successful returns
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_cu_header_offset\fP to
the offset
in the .debug_info section of the compilation-unit header for the 
compilation-unit represented by the given address range.
It returns \f(CWDW_DLV_ERROR\fP on error.

This function added Rev 1.45, June, 2001.

This function is declared as 'optional' in libdwarf.h
on IRIX systems so the _MIPS_SYMBOL_PRESENT
predicate may be used at run time to determine if the version of
libdwarf linked into an application has this function.



.H 3 "dwarf_get_arange_info()"
.DS
\f(CWint dwarf_get_arange_info(
        Dwarf_Arange arange,
        Dwarf_Addr *start,
        Dwarf_Unsigned *length,
        Dwarf_Off *cu_die_offset,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_arange_info()\fP returns
\f(CWDW_DLV_OK\fP
and
stores the starting value of the address range in the location pointed 
to by \f(CWstart\fP, the length of the address range in the location 
pointed to by \f(CWlength\fP, and the offset in the .debug_info section 
of the compilation-unit DIE for the compilation-unit represented by the 
address range.
It returns \f(CWDW_DLV_ERROR\fP on error.

.H 2 "General Low Level Operations"
This function is low-level and intended for use only
by programs such as dwarf-dumpers.

.H 3 "dwarf_get_address_size()"
.DS
\f(CWint dwarf_get_address_size(Dwarf_Debug dbg,
	Dwarf_Half  *addr_size,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_address_size()\fP 
returns \f(CWDW_DLV_OK\fP on success and sets 
the \f(CW*addr_size\fP
to the size in bytes of an address.
In case of error, it returns \f(CWDW_DLV_ERROR\fP
and does not set \f(CW*addr_size\fP.

The address size returned is the overall address size,
which can be misleading if different compilation
units have different address sizes.
Many ABIs have only a single address size per
executable, but differing address sizes are
becoming more common.

Use \f(CWdwarf_get_die_address_size()\fP 
instead whenever possible.

.H 3 "dwarf_get_die_address_size()"
.DS
\f(CWint dwarf_get_die_address_size(Dwarf_Die die,
	Dwarf_Half  *addr_size,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_die_address_size()\fP 
returns \f(CWDW_DLV_OK\fP on success and sets 
the \f(CW*addr_size\fP
to the size in bytes of an address.
In case of error, it returns \f(CWDW_DLV_ERROR\fP
and does not set \f(CW*addr_size\fP.

The address size returned is the address size 
of the compilation unit owning the \f(CWdie\fP

This is the preferred way to get address size when the
\f(CWDwarf_Die\fP is known.


.H 2 "Ranges Operations (.debug_ranges)"


.H 2 "Ranges Operations (.debug_ranges)"
These functions provide information about the address ranges
indicated by a  \f(CWDW_AT_ranges\fP attribute (the ranges are recorded
in the  \f(CW.debug_ranges\fP section) of a DIE.  
Each call of \f(CWdwarf_get_ranges_a()\fP 
or \f(CWdwarf_get_ranges()\fP 
returns a an array
of Dwarf_Ranges structs, each of which represents a single ranges
entry.   The struct is defined in  \f(CWlibdwarf.h\fP.


.H 3 "dwarf_get_ranges()"
This is the original call and it will work fine when
all compilation units have the same address_size.
There is no \f(CWdie\fP argument to this original
version of the function. 
Other arguments (and deallocation) match the use
of  \f(CWdwarf_get_ranges_a()\fP ( described next).

.H 3 "dwarf_get_ranges_a()"
.DS
\f(CWint dwarf_get_ranges_a(
        Dwarf_Debug dbg,
        Dwarf_Off  offset,
        Dwarf_Die  die,
        Dwarf_Ranges **ranges,
        Dwarf_Signed * returned_ranges_count,
        Dwarf_Unsigned * returned_byte_count,
        Dwarf_Error *error)\fP
.DE
The function \f(CWdwarf_get_ranges_a()\fP returns 
\f(CWDW_DLV_OK\fP and sets \f(CW*returned_ranges_count\fP to
the count of the
number of address ranges in the group of ranges 
in the .debug_ranges section at offset  \f(CWoffset\fP
(which ends with a pair of zeros of pointer-size).
This function is new as of 27 April 2009.

The
\f(CWoffset\fP argument should be the value of 
a \f(CWDW_AT_ranges\fP attribute of a Debugging Information Entry. 

The
\f(CWdie\fP argument should be the value of 
a \f(CWDwarf_Die\fP pointer of a \f(CWDwarf_Die\fP with
the attribute containing
this range set offset.  Because each compilation unit
has its own address_size field this argument is necessary to
to correctly read ranges. (Most executables have the
same address_size in every compilation unit, but
some ABIs allow multiple address sized in an executable).
If a NULL pointer is passed in libdwarf assumes
a single address_size is appropriate for all ranges records.

The call sets
\f(CW*ranges\fP to point to a block of \f(CWDwarf_Ranges\fP 
structs, one for each address range.  
It returns \f(CWDW_DLV_ERROR\fP on error.
It returns \f(CWDW_DLV_NO_ENTRY\fP if there is no  \f(CW.debug_ranges\fP 
section or if \f(CWoffset\fP is past the end of the  
\f(CW.debug_ranges\fP section.

If the \f(CW*returned_byte_count\fP pointer is passed as non-NULL
the number of bytes that the returned ranges
were taken from is returned through the pointer
(for example if the returned_ranges_count is 2 and the pointer-size
is 4, then returned_byte_count will be 8).
If the \f(CW*returned_byte_count\fP pointer is passed as NULL
the parameter is ignored.
The \f(CW*returned_byte_count\fP is only of use to certain
dumper applications, most applications will not use it.


.in +2
.DS
\f(CWDwarf_Signed cnt;
Dwarf_Ranges *ranges;
Dwarf_Unsigned bytes;
int res;
res = dwarf_get_ranges_a(dbg,off,dieptr, &ranges,&cnt,&bytes,&error);
if (res == DW_DLV_OK) {
        Dwarf_Signed i;
        for( i = 0; i < cnt; ++i ) {
            Dwarf_Ranges *cur = ranges+i;
            /* Use cur. */
        }
        dwarf_ranges_dealloc(dbg,ranges,cnt);
}\fP
.DE
.in -2

.H 3 "dwarf_ranges_dealloc()"
.DS
\f(CWint dwarf_ranges_dealloc(
        Dwarf_Debug dbg,
        Dwarf_Ranges *ranges,
        Dwarf_Signed  range_count,
        );\fP
.DE
The function \f(CWdwarf_ranges_dealloc()\fP takes as input a pointer 
to a block of \f(CWDwarf_Ranges\fP array and the 
number of structures in the block.  
It frees all the data in the array of structures.

.H 2 "TAG ATTR etc names as strings"
These functions turn a value into a string.  
So applications wanting the string "DW_TAG_compile_unit"
given the value 0x11 (the value defined for this TAG) can do so easily.

The general form is
.in +2
.DS
\f(CWint dwarf_get_<something>_name(
        unsigned value,
        char **s_out,
        );\fP
.DE
.in -2

If the \f(CWvalue\fP passed in is known, the function
returns \f(CWDW_DLV_OK\fP and places a pointer to the appropriate string
into  \f(CW*s_out\fP.   The string is in static storage
and applications must never free the string.
If the \f(CWvalue\fP is not known, \f(CWDW_DLV_NO_ENTRY\fP is returned
and \f(CW*s_out\fP is not set.  \f(CWDW_DLV_ERROR\fP is never returned.

\f(CWLibdwarf\fP generates these functions at libdwarf build time
by reading dwarf.h.

All these follow this pattern rigidly, so the details of each
are not repeated for each function.

The choice of 'unsigned' for the value type argument (the code value)
argument is somewhat arbitrary, 'int' could have been used.

The library simply assumes the value passed in is applicable.
So, for example,
passing a TAG value code to  \f(CWdwarf_get_ACCESS_name()\fP
is a coding error which libdwarf will process as if it was
an accessibility code value.
Examples of bad and good usage are:

.in +2
.DS
\f(CW
     const char * out;
     int res;
     /* The following is wrong, do not do it! */
     res = dwarf_get_ACCESS_name(DW_TAG_entry_point,&out);
     /* Nothing one does here with 'res' or 'out'
        is meaningful. */

     /* The following is meaningful.*/
     res = dwarf_get_TAG_name(DW_TAG_entry_point,&out);
     if( res == DW_DLV_OK) {
        /* Here 'out' is a pointer one can use which
           points to the string "DW_TAG_entry_point". */
     } else {
        /* Here 'out' has not been touched, it is 
           uninitialized.  Do not use it. */
     }
\fP
.DE
.in -2




.H 2 "dwarf_get_ACCESS_name()"
Returns an accessibility code name  through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_AT_name()"
Returns an attribute code name  through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_ATE_name()"
Returns a base type encoding name  through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_ADDR_name()"
Returns an address type encoding name  through the \f(CWs_out\fP pointer.
As of this writing only  \f(CWDW_ADDR_none\fP is defined in  \f(CWdwarf.h\fP.
.H 2 "dwarf_get_ATCF_name()"
Returns a SUN code flag encoding name  through the \f(CWs_out\fP pointer.
This code flag is entirely a DWARF extension.
.H 2 "dwarf_get_CHILDREN_name()"
Returns a child determination name (which
is seen in the abbreviations section data) through the \f(CWs_out\fP pointer.
The only value this recognizes for a 'yes' value is 1.
As a flag value this is not quite correct (any non-zero value means
yes) but dealing with this is left up to client code (normally
compilers really do emit a value of 1 for a flag).
.H 2 "dwarf_get_children_name()"
Returns a child determination name through the \f(CWs_out\fP pointer,
though this version is really a libdwarf artifact.
The standard function is  \f(CWdwarf_get_CHILDREN_name()\fP
which appears just above.
As a flag value this is not quite correct (any non-zero value means
yes) but dealing with this is left up to client code (normally
compilers really do emit a value of 1 for a flag).
.H 2 "dwarf_get_CC_name()"
Returns  a calling convention case code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_CFA_name()"
Returns  a call frame information instruction
name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_DS_name()"
Returns a decimal sign code name  through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_DSC_name()"
Returns  a discriminant descriptor code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_EH_name()"
Returns  a GNU exception header
code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_END_name()"
Returns an endian code name  through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_FORM_name()"
Returns an form code name  through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_FRAME_name()"
Returns a frame code name  through the \f(CWs_out\fP pointer.
These are dependent on the particular ABI, so unless the
\f(CWdwarf.h\fP used to generate libdwarf matches your ABI
these names are unlikely to be very useful and certainly
won't be entirely appropriate.
.H 2 "dwarf_get_ID_name()"
Returns  an identifier case code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_INL_name()"
Returns  an inline code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_LANG_name()"
Returns  a language code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_LNE_name()"
Returns  a line table extended
opcode code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_LNS_name()"
Returns  a line table standard
opcode code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_MACINFO_name()"
Returns  a macro information macinfo
code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_OP_name()"
Returns  a DWARF expression operation
code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_ORD_name()"
Returns  an array ordering code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_TAG_name()"
Returns  a TAG name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_VIRTUALITY_name()"
Returns  a virtuality code name through the \f(CWs_out\fP pointer.
.H 2 "dwarf_get_VIS_name()"
Returns a visibility code name  through the \f(CWs_out\fP pointer.


.H 2 "Section Operations"
In checking DWARF in linkonce sections for correctness
it has been found useful to have certain section-oriented
operations when processing object files.
Normally these operations are not needed or useful
in a fully-linked executable or shared library.

While the code is written with Elf sections in mind,
it is quite possible to process  non-Elf objects
with code that implements certain function pointers
(see \f(CWstruct Dwarf_Obj_Access_interface_s\fP).

So far no one with such non-elf code has come forward
to open-source it.

.H 3 "dwarf_get_section_count()"
.DS
\f(CWint dwarf_get_section_count(
   Dwarf_Debug dbg) \fP
.DE 

Returns a count of the number of object sections found.



.H 3 "dwarf_get_section_info_by_name()"
.DS
\f(CWint dwarf_get_section_info_by_name(
   const char *section_name,
   Dwarf_Addr *section_addr,
   Dwarf_Unsigned *section_size,
   Dwarf_Error *error)\fP
.DE 
The function \f(CWdwarf_get_section_info_by_name()\fP 
returns \f(CWDW_DLV_OK\fP if the section given by \f(CWsection_name\fP
was seen by libdwarf.
On success it sets \f(CW*section_addr\fP to the virtual address 
assigned to the section by the linker or compiler and \f(CW*section_size\fP
to the size of the object section.

It returns DW_DLV_ERROR on error.
.H 3 "dwarf_get_section_info_by_index()"
.DS
\f(CWint dwarf_get_section_info_by_index(
   int section_index,
   const char **section_name,
   Dwarf_Addr *section_addr,
   Dwarf_Unsigned *section_size,
   Dwarf_Error *error)\fP
.DE 
The function \f(CWdwarf_get_section_info_by_index()\fP 
returns \f(CWDW_DLV_OK\fP if the section given by \f(CWsection_index\fP
was seen by libdwarf.
\f(CW*section_addr\fP to the virtual address 
assigned to the section by the linker or compiler 
and \f(CW*section_size\fP
to the size of the object section.

No free or deallocate of information returned should be done by
callers.


.H 2 "Utility Operations"
These functions aid in the management of errors encountered when using 
functions in the \fIlibdwarf\fP library and releasing memory allocated 
as a result of a \fIlibdwarf\fP operation. 

.H 3 "dwarf_errno()"
.DS
\f(CWDwarf_Unsigned dwarf_errno(
        Dwarf_Error error)\fP
.DE
The function \f(CWdwarf_errno()\fP returns the error number corresponding 
to the error specified by \f(CWerror\fP.

.H 3 "dwarf_errmsg()"
.DS
\f(CWconst char* dwarf_errmsg(
        Dwarf_Error error)\fP
.DE
The function \f(CWdwarf_errmsg()\fP returns a pointer to a
null-terminated error message string corresponding to the error specified by 
\f(CWerror\fP.  
The string returned by \f(CWdwarf_errmsg()\fP 
should not be deallocated using \f(CWdwarf_dealloc()\fP.

.H 3 "dwarf_get_harmless_error_list()"
.DS
\f(CWint dwarf_get_harmless_error_list(Dwarf_Debug dbg,
    unsigned  count,
    const char ** errmsg_ptrs_array,
    unsigned * newerr_count);\fP
.DE
The harmless errors are not denoted by error returns from
the other libdwarf functions.  Instead, this function
returns strings of any harmless errors that have been
seen in the current object.  Clients never need call this, but
if a client wishes to report any such errors it may call.

Only a fixed number of harmless errors are recorded. It
is a circular list, so if more than the current maximum
is encountered older harmless error messages are lost.

The caller passes in a pointer to an array of pointer-to-char 
as the argument \f(CWerrmsg_ptrs_array\fP.  The caller
must provide this array, libdwarf does not provide it.
The caller need not initialize the array elements.

The caller passes in the number of elements of the array of
pointer-to-char thru \f(CWcount\fP.   Since the

If there are no unreported harmless errors the function
returns \f(CWDW_DLV_NO_ENTRY\fP and the function arguments
are ignored.
Otherwise the function returns \f(CWDW_DLV_OK\fP
and uses the arguments.

\f(CWlibdwarf\fP assigns error strings to the errmsg_ptrs_array.
The MININUM(count-1, number of messages recorded) pointers are assigned
to the array.  The array is terminated with a NULL pointer.
(That is, one array entry is reserved for a NULL pointer).
So if \f(CWcount\fP is 5 up to 4 strings may be returned through
the array, and one array entry is set to NULL.

Because the list is circular and messages may have been dropped
the function also returns the actual error count of harmless
errors encountered through \f(CWnewerr_count\fP
(unless the argument is NULL, in which case it is ignored).

Each call to this function resets the circular error buffer and
the error count.   
So think of this call as reporting harmless errors since the
last call to it.

The pointers returned through \f(CWerrmsg_ptrs_array\fP
are only valid till the next call to libdwarf.  
Do not save the pointers, they become invalid.  Copy the strings
if you wish to save them.

Calling this function neither allocates any space in memory nor
frees any space in memory.


.H 3 "dwarf_insert_harmless_error()"
.DS
void dwarf_insert_harmless_error(Dwarf_Debug dbg,
    char * newerror);
.DE
This function is used to test 
\f(CWdwarf_get_harmless_error_list\fP. It simply adds
a harmless error string.  
There is little reason client code should use this function.
It exists so that the harmless error functions can be
easily tested for correctness and leaks.

.H 3 "dwarf_set_harmless_error_list_size()"
.DS
\f(CWunsigned dwarf_set_harmless_error_list_size(Dwarf_Debug dbg,
    unsigned maxcount)\fP
.DE
\f(CWdwarf_set_harmless_error_list_size\fP returns the
number of harmless error strings the library is currently
set to hold. 
If \f(CWmaxcount\fP is non-zero the library changes the
maximum it will record to be \f(CWmaxcount\fP.

It is extremely unwise to make \f(CWmaxcount\fP large because
\f(CWlibdwarf\fP allocates space for \f(CWmaxcount\fP
strings immediately.

.P
The set of errors 
enumerated in Figure \n(aX below were defined in Dwarf 1.
These errors are not used by the \f(CWlibdwarf\fP implementation
for Dwarf 2 or later.  
.DS
.TS
center box, tab(:);
lfB lfB 
l l.
SYMBOLIC NAME:DESCRIPTION
_
DW_DLE_NE:No error (0)
DW_DLE_VMM:Version of DWARF information newer than libdwarf
DW_DLE_MAP:Memory map failure
DW_DLE_LEE:Propagation of libelf error
DW_DLE_NDS:No debug section
DW_DLE_NLS:No line section
DW_DLE_ID:Requested information not associated with descriptor
DW_DLE_IOF:I/O failure
DW_DLE_MAF:Memory allocation failure
DW_DLE_IA:Invalid argument
DW_DLE_MDE:Mangled debugging entry
DW_DLE_MLE:Mangled line number entry
DW_DLE_FNO:File descriptor does not refer to an open file
DW_DLE_FNR:File is not a regular file
DW_DLE_FWA:File is opened with wrong access
DW_DLE_NOB:File is not an object file
DW_DLE_MOF:Mangled object file header
DW_DLE_EOLL:End of location list entries
DW_DLE_NOLL:No location list section
DW_DLE_BADOFF:Invalid offset
DW_DLE_EOS:End of section
DW_DLE_ATRUNC:Abbreviations section appears truncated
DW_DLE_BADBITC:Address size passed to dwarf bad
.TE
.FG "List of Dwarf Error Codes"
.DE

The set of errors returned by \f(CWLibdwarf\fP functions
is listed below.
Some of the errors are SGI specific.

.DS
.TS
center box, tab(:);
lfB lfB
l l.
SYMBOLIC NAME:DESCRIPTION
_
DW_DLE_DBG_ALLOC:Could not allocate Dwarf_Debug struct
DW_DLE_FSTAT_ERROR:Error in fstat()-ing object
DW_DLE_FSTAT_MODE_ERROR:Error in mode of object file
DW_DLE_INIT_ACCESS_WRONG:Incorrect access to dwarf_init()
DW_DLE_ELF_BEGIN_ERROR:Error in elf_begin() on object
DW_DLE_ELF_GETEHDR_ERROR:Error in elf_getehdr() on object
DW_DLE_ELF_GETSHDR_ERROR:Error in elf_getshdr() on object
DW_DLE_ELF_STRPTR_ERROR:Error in elf_strptr() on object
DW_DLE_DEBUG_INFO_DUPLICATE:Multiple .debug_info sections
DW_DLE_DEBUG_INFO_NULL:No data in .debug_info section
DW_DLE_DEBUG_ABBREV_DUPLICATE:Multiple .debug_abbrev sections
DW_DLE_DEBUG_ABBREV_NULL:No data in .debug_abbrev section
DW_DLE_DEBUG_ARANGES_DUPLICATE:Multiple .debug_arange sections
DW_DLE_DEBUG_ARANGES_NULL:No data in .debug_arange section
DW_DLE_DEBUG_LINE_DUPLICATE:Multiple .debug_line sections
DW_DLE_DEBUG_LINE_NULL:No data in .debug_line section
DW_DLE_DEBUG_LOC_DUPLICATE:Multiple .debug_loc sections
DW_DLE_DEBUG_LOC_NULL:No data in .debug_loc section
DW_DLE_DEBUG_MACINFO_DUPLICATE:Multiple .debug_macinfo sections
DW_DLE_DEBUG_MACINFO_NULL:No data in .debug_macinfo section
DW_DLE_DEBUG_PUBNAMES_DUPLICATE:Multiple .debug_pubnames sections
DW_DLE_DEBUG_PUBNAMES_NULL:No data in .debug_pubnames section
DW_DLE_DEBUG_STR_DUPLICATE:Multiple .debug_str sections
DW_DLE_DEBUG_STR_NULL:No data in .debug_str section
DW_DLE_CU_LENGTH_ERROR:Length of compilation-unit bad
DW_DLE_VERSION_STAMP_ERROR:Incorrect Version Stamp
DW_DLE_ABBREV_OFFSET_ERROR:Offset in .debug_abbrev bad
DW_DLE_ADDRESS_SIZE_ERROR:Size of addresses in target bad
DW_DLE_DEBUG_INFO_PTR_NULL:Pointer into .debug_info in DIE null
DW_DLE_DIE_NULL:Null Dwarf_Die
DW_DLE_STRING_OFFSET_BAD:Offset in .debug_str bad
DW_DLE_DEBUG_LINE_LENGTH_BAD:Length of .debug_line segment bad
DW_DLE_LINE_PROLOG_LENGTH_BAD:Length of .debug_line prolog bad
DW_DLE_LINE_NUM_OPERANDS_BAD:Number of operands to line instr bad
DW_DLE_LINE_SET_ADDR_ERROR:Error in DW_LNE_set_address instruction
DW_DLE_LINE_EXT_OPCODE_BAD:Error in DW_EXTENDED_OPCODE instruction
DW_DLE_DWARF_LINE_NULL:Null Dwarf_line argument
DW_DLE_INCL_DIR_NUM_BAD:Error in included directory for given line
DW_DLE_LINE_FILE_NUM_BAD:File number in .debug_line bad
DW_DLE_ALLOC_FAIL:Failed to allocate required structs
DW_DLE_DBG_NULL:Null Dwarf_Debug argument
DW_DLE_DEBUG_FRAME_LENGTH_BAD:Error in length of frame
DW_DLE_FRAME_VERSION_BAD:Bad version stamp for frame
DW_DLE_CIE_RET_ADDR_REG_ERROR:Bad register specified for return address
DW_DLE_FDE_NULL:Null Dwarf_Fde argument
DW_DLE_FDE_DBG_NULL:No Dwarf_Debug associated with FDE
DW_DLE_CIE_NULL:Null Dwarf_Cie argument
DW_DLE_CIE_DBG_NULL:No Dwarf_Debug associated with CIE
DW_DLE_FRAME_TABLE_COL_BAD:Bad column in frame table specified
.TE
.FG "List of Dwarf 2 Error Codes (continued)"
.DE

.DS
.TS
center box, tab(:);
lfB lfB
l l.
SYMBOLIC NAME:DESCRIPTION
_
DW_DLE_PC_NOT_IN_FDE_RANGE:PC requested not in address range of FDE
DW_DLE_CIE_INSTR_EXEC_ERROR:Error in executing instructions in CIE
DW_DLE_FRAME_INSTR_EXEC_ERROR:Error in executing instructions in FDE
DW_DLE_FDE_PTR_NULL:Null Pointer to Dwarf_Fde specified
DW_DLE_RET_OP_LIST_NULL:No location to store pointer to Dwarf_Frame_Op
DW_DLE_LINE_CONTEXT_NULL:Dwarf_Line has no context
DW_DLE_DBG_NO_CU_CONTEXT:dbg has no CU context for dwarf_siblingof()
DW_DLE_DIE_NO_CU_CONTEXT:Dwarf_Die has no CU context
DW_DLE_FIRST_DIE_NOT_CU:First DIE in CU not DW_TAG_compilation_unit
DW_DLE_NEXT_DIE_PTR_NULL:Error in moving to next DIE in .debug_info
DW_DLE_DEBUG_FRAME_DUPLICATE:Multiple .debug_frame sections
DW_DLE_DEBUG_FRAME_NULL:No data in .debug_frame section
DW_DLE_ABBREV_DECODE_ERROR:Error in decoding abbreviation
DW_DLE_DWARF_ABBREV_NULL:Null Dwarf_Abbrev specified
DW_DLE_ATTR_NULL:Null Dwarf_Attribute specified
DW_DLE_DIE_BAD:DIE bad
DW_DLE_DIE_ABBREV_BAD:No abbreviation found for code in DIE
DW_DLE_ATTR_FORM_BAD:Inappropriate attribute form for attribute
DW_DLE_ATTR_NO_CU_CONTEXT:No CU context for Dwarf_Attribute struct
DW_DLE_ATTR_FORM_SIZE_BAD:Size of block in attribute value bad
DW_DLE_ATTR_DBG_NULL:No Dwarf_Debug for Dwarf_Attribute struct
DW_DLE_BAD_REF_FORM:Inappropriate form for reference attribute
DW_DLE_ATTR_FORM_OFFSET_BAD:Offset reference attribute outside current CU
DW_DLE_LINE_OFFSET_BAD:Offset of lines for current CU outside .debug_line
DW_DLE_DEBUG_STR_OFFSET_BAD:Offset into .debug_str past its end
DW_DLE_STRING_PTR_NULL:Pointer to pointer into .debug_str NULL
DW_DLE_PUBNAMES_VERSION_ERROR:Version stamp of pubnames incorrect
DW_DLE_PUBNAMES_LENGTH_BAD:Read pubnames past end of .debug_pubnames
DW_DLE_GLOBAL_NULL:Null Dwarf_Global specified
DW_DLE_GLOBAL_CONTEXT_NULL:No context for Dwarf_Global given
DW_DLE_DIR_INDEX_BAD:Error in directory index read
DW_DLE_LOC_EXPR_BAD:Bad operator read for location expression
DW_DLE_DIE_LOC_EXPR_BAD:Expected block value for attribute not found
DW_DLE_OFFSET_BAD:Offset for next compilation-unit in .debug_info bad
DW_DLE_MAKE_CU_CONTEXT_FAIL:Could not make CU context
DW_DLE_ARANGE_OFFSET_BAD:Offset into .debug_info in .debug_aranges bad
DW_DLE_SEGMENT_SIZE_BAD:Segment size will be 0 for MIPS processors and should always be < 8.
DW_DLE_ARANGE_LENGTH_BAD:Length of arange section in .debug_arange bad
DW_DLE_ARANGE_DECODE_ERROR:Aranges do not end at end of .debug_aranges
DW_DLE_ARANGES_NULL:NULL pointer to Dwarf_Arange specified
DW_DLE_ARANGE_NULL:NULL Dwarf_Arange specified
DW_DLE_NO_FILE_NAME:No file name for Dwarf_Line struct
DW_DLE_NO_COMP_DIR:No Compilation directory for compilation-unit
DW_DLE_CU_ADDRESS_SIZE_BAD:CU header address size not match Elf class
DW_DLE_ELF_GETIDENT_ERROR:Error in elf_getident() on object
DW_DLE_NO_AT_MIPS_FDE:DIE does not have DW_AT_MIPS_fde attribute
DW_DLE_NO_CIE_FOR_FDE:No CIE specified for FDE
DW_DLE_DIE_ABBREV_LIST_NULL:No abbreviation for the code in DIE found
DW_DLE_DEBUG_FUNCNAMES_DUPLICATE:Multiple .debug_funcnames sections
DW_DLE_DEBUG_FUNCNAMES_NULL:No data in .debug_funcnames section
.TE
.FG "List of Dwarf 2 Error Codes (continued)"
.DE

.DS
.TS
center box, tab(:);
lfB lfB
l l.
SYMBOLIC NAME:DESCRIPTION
_
DW_DLE_DEBUG_FUNCNAMES_VERSION_ERROR:Version stamp in .debug_funcnames bad
DW_DLE_DEBUG_FUNCNAMES_LENGTH_BAD:Length error in reading .debug_funcnames
DW_DLE_FUNC_NULL:NULL Dwarf_Func specified
DW_DLE_FUNC_CONTEXT_NULL:No context for Dwarf_Func struct
DW_DLE_DEBUG_TYPENAMES_DUPLICATE:Multiple .debug_typenames sections
DW_DLE_DEBUG_TYPENAMES_NULL:No data in .debug_typenames section
DW_DLE_DEBUG_TYPENAMES_VERSION_ERROR:Version stamp in .debug_typenames bad
DW_DLE_DEBUG_TYPENAMES_LENGTH_BAD:Length error in reading .debug_typenames
DW_DLE_TYPE_NULL:NULL Dwarf_Type specified
DW_DLE_TYPE_CONTEXT_NULL:No context for Dwarf_Type given
DW_DLE_DEBUG_VARNAMES_DUPLICATE:Multiple .debug_varnames sections
DW_DLE_DEBUG_VARNAMES_NULL:No data in .debug_varnames section
DW_DLE_DEBUG_VARNAMES_VERSION_ERROR:Version stamp in .debug_varnames bad
DW_DLE_DEBUG_VARNAMES_LENGTH_BAD:Length error in reading .debug_varnames
DW_DLE_VAR_NULL:NULL Dwarf_Var specified
DW_DLE_VAR_CONTEXT_NULL:No context for Dwarf_Var given
DW_DLE_DEBUG_WEAKNAMES_DUPLICATE:Multiple .debug_weaknames section
DW_DLE_DEBUG_WEAKNAMES_NULL:No data in .debug_varnames section
DW_DLE_DEBUG_WEAKNAMES_VERSION_ERROR:Version stamp in .debug_varnames bad
DW_DLE_DEBUG_WEAKNAMES_LENGTH_BAD:Length error in reading .debug_weaknames
DW_DLE_WEAK_NULL:NULL Dwarf_Weak specified
DW_DLE_WEAK_CONTEXT_NULL:No context for Dwarf_Weak given
.TE
.FG "List of Dwarf 2 Error Codes"
.DE

This list of errors is not complete;
additional errors have been added.
Some of the above errors may be unused.
Errors may not have the same meaning in different releases.
Since most error codes are returned from only one  place
(or a very small number of places) in the source
it is normally very useful to simply search the 
\f(CWlibdwarf\fP source to find
out where a particular error code is generated.

.H 3 "dwarf_seterrhand()"
.DS
\f(CWDwarf_Handler dwarf_seterrhand(
        Dwarf_Debug dbg,
        Dwarf_Handler errhand)\fP
.DE
The function \f(CWdwarf_seterrhand()\fP replaces the error handler 
(see \f(CWdwarf_init()\fP) with \f(CWerrhand\fP.  The old error handler 
is returned.  This function is currently unimplemented.

.H 3 "dwarf_seterrarg()"
.DS
\f(CWDwarf_Ptr dwarf_seterrarg(
        Dwarf_Debug dbg,
        Dwarf_Ptr errarg)\fP
.DE
The function \f(CWdwarf_seterrarg()\fP replaces the pointer to the 
error handler communication area (see \f(CWdwarf_init()\fP) with 
\f(CWerrarg\fP.  A pointer to the old area is returned.  This
function is currently unimplemented.

.H 3 "dwarf_dealloc()"
.DS
\f(CWvoid dwarf_dealloc(
        Dwarf_Debug dbg,
        void* space, 
        Dwarf_Unsigned type)\fP
.DE
The function \f(CWdwarf_dealloc\fP frees the dynamic storage pointed
to by \f(CWspace\fP, and allocated to the given \f(CWDwarf_Debug\fP.
The argument \f(CWtype\fP is an integer code that specifies the allocation 
type of the region pointed to by the \f(CWspace\fP.  Refer to section 
4 for details on \fIlibdwarf\fP memory management.

.SK
.S
.TC 1 1 4
.CS