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.\"
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.\" Copyright (c) 2001, The IEEE and The Open Group. All Rights Reserved.
.\" Portions Copyright (c) 2006, Sun Microsystems, Inc. All Rights Reserved.
.\"
.TH FEGETENV 3M "Jul 12, 2006" "SunOS 5.11" "Mathematical Library Functions"
.SH NAME
fegetenv, fesetenv \- get and set current floating-point environment
.SH SYNOPSIS
.LP
.nf
c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
#include <fenv.h>
\fBint\fR \fBfegetenv\fR(\fBfenv_t *\fR\fIenvp\fR);
.fi
.LP
.nf
\fBint\fR \fBfesetenv\fR(\fBconst fenv_t *\fR\fIenvp\fR);
.fi
.SH DESCRIPTION
.sp
.LP
The \fBfegetenv()\fR function attempts to store the current floating-point
environment in the object pointed to by \fIenvp\fR.
.sp
.LP
The \fBfesetenv()\fR function attempts to establish the floating-point
environment represented by the object pointed to by \fIenvp\fR. The \fIenvp\fR
argument points to an object set by a call to \fBfegetenv()\fR or
\fBfeholdexcept\fR(3M), or equals a floating-point environment macro. The
\fBfesetenv()\fR function does not raise floating-point exceptions, but only
installs the state of the floating-point status flags represented through its
argument.
.SH RETURN VALUES
.sp
.LP
If the representation was successfully stored, fegetenv returns 0. Otherwise,
it returns a non-zero value.
.sp
.LP
If the environment was successfully established, fesetenv returns 0. Otherwise,
it returns a non-zero value.
.SH ERRORS
.sp
.LP
No errors are defined.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp
.sp
.TS
tab( ) box;
cw(2.75i) |cw(2.75i)
lw(2.75i) |lw(2.75i)
.
ATTRIBUTE TYPE ATTRIBUTE VALUE
_
Interface Stability Standard
_
MT-Level MT-Safe
.TE
.SH SEE ALSO
.sp
.LP
\fBfeholdexcept\fR(3M), \fBfenv.h\fR(3HEAD), \fBfeupdateenv\fR(3M),
\fBattributes\fR(5), \fBstandards\fR(5)
.SH NOTES
.sp
.LP
In a multithreaded program, the \fBfegetenv()\fR and \fBfegetenv()\fR functions
affect the floating point environment only for the calling thread.
.sp
.LP
These functions automatically install and deinstall \fBSIGFPE\fR handlers and
set and clear the trap enable mode bits in the floating point status register
as needed. If a program uses these functions and attempts to install a
\fBSIGFPE\fR handler or control the trap enable mode bits independently, the
resulting behavior is not defined.
.sp
.LP
As described in \fBfex_set_handling\fR(3M)\fB\fR, when a handling function
installed in \fBFEX_CUSTOM\fR mode is invoked, all exception traps are disabled
(and will not be reenabled while \fBSIGFPE\fR is blocked). Thus, attempting to
change the environment from within a handler by calling \fBfesetenv\fR or
\fBfeupdateenv\fR(3M) might not produce the expected results.
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