.\" Copyright (c) 2006 Joseph Koshy.  All rights reserved.
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.\" $FreeBSD: src/lib/libelf/gelf_getehdr.3,v 1.4.10.2.2.1 2010/12/21 17:09:25 kensmith Exp $
.\"
.Dd December 16, 2006
.Dt GELF_GETEHDR 3
.Os
.Sh NAME
.Nm elf32_getehdr ,
.Nm elf64_getehdr ,
.Nm gelf_getehdr
.Nd retrieve the object file header
.Sh LIBRARY
.Lb libelf
.Sh SYNOPSIS
.In libelf.h
.Ft "Elf32_Ehdr *"
.Fn elf32_getehdr "Elf *elf"
.Ft "Elf64_Ehdr *"
.Fn elf64_getehdr "Elf *elf"
.In gelf.h
.Ft "GElf_Ehdr *"
.Fn gelf_getehdr "Elf *elf" "GElf_Ehdr *dst"
.Sh DESCRIPTION
These functions retrieve the ELF object file
header from the ELF descriptor
.Ar elf
and return a translated header descriptor to their callers.
.Pp
Functions
.Fn elf32_getehdr
and
.Fn elf64_getehdr
return a pointer to the appropriate class-specific header descriptor
if it exists in the file referenced by descriptor
.Ar elf .
These functions return
.Dv NULL
if an ELF header was not found in file
.Ar elf .
.Pp
Function
.Fn gelf_getehdr
stores a translated copy of the header for ELF file
.Ar elf
into the descriptor pointed to by argument
.Ar dst .
It returns argument
.Ar dst
if successful or
.Dv NULL
in case of failure.
.Sh RETURN VALUES
These functions return a pointer to a translated header descriptor
if successful, or NULL on failure.
.Sh ERRORS
These functions can fail with the following errors:
.Bl -tag -width "[ELF_E_RESOURCE]"
.It Bq Er ELF_E_ARGUMENT
The argument
.Ar elf
was null.
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar elf
was not a descriptor for an ELF file.
.It Bq Er ELF_E_ARGUMENT
The elf class of descriptor
.Ar elf
was not recognized.
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar dst
was null.
.It Bq Er ELF_E_CLASS
The ELF class of descriptor
.Ar elf
did not match that of the API function being called.
.It Bq Er ELF_E_HEADER
ELF descriptor
.Ar elf
does not have an associated header.
.It Bq Er ELF_E_RESOURCE
An out of memory condition was detected during execution.
.It Bq Er ELF_E_SECTION
The ELF descriptor in argument
.Ar elf
did not adhere to the conventions used for extended numbering.
.It Bq Er ELF_E_VERSION
The ELF descriptor
.Ar elf
had an unsupported ELF version number.
.El
.Sh SEE ALSO
.Xr elf 3 ,
.Xr elf32_newehdr 3 ,
.Xr elf64_newehdr 3 ,
.Xr elf_flagehdr 3 ,
.Xr elf_getident 3 ,
.Xr gelf 3 ,
.Xr gelf_newehdr 3 ,
.Xr elf 5