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FECLEAREXCEPT(3) FreeBSD Library Functions Manual FECLEAREXCEPT(3)
NAME
feclearexcept, fegetexceptflag, feraiseexcept, fesetexceptflag,
fetestexcept - floating-point exception flag manipulation
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <fenv.h>
#pragma STDC FENV_ACCESS ON
int
feclearexcept(int excepts);
int
fegetexceptflag(fexcept_t *flagp, int excepts);
int
feraiseexcept(int excepts);
int
fesetexceptflag(const fexcept_t *flagp, int excepts);
int
fetestexcept(int excepts);
DESCRIPTION
The feclearexcept() routine clears the floating-point exception flags
specified by excepts, whereas feraiseexcept() raises the specified
exceptions. Raising an exception causes the corresponding flag to be
set, and a SIGFPE is delivered to the process if the exception is
unmasked.
The fetestexcept() function determines which flags are currently set, of
those specified by excepts.
The fegetexceptflag() function stores the state of the exception flags
specified in excepts in the opaque object pointed to by flagp.
Similarly, fesetexceptflag() changes the specified exception flags to
reflect the state stored in the object pointed to by flagp. Note that
the flags restored with fesetexceptflag() must be a (not necessarily
proper) subset of the flags recorded by a prior call to
fegetexceptflag().
For all of these functions, the possible types of exceptions include
those described in fenv(3). Some architectures may define other types of
floating-point exceptions.
IMPLEMENTATION NOTES
On some architectures, raising an overflow or underflow exception also
causes an inexact exception to be raised. In these cases, the overflow
or underflow will be raised first.
The fegetexceptflag() and fesetexceptflag() routines are preferred to
fetestexcept() and feraiseexcept(), respectively, for saving and
restoring exception flags. The latter do not re-raise exceptions and may
values of the current exception flags that were requested.
SEE ALSO
sigaction(2), feholdexcept(3), fenv(3), feupdateenv(3), fpgetsticky(3),
fpresetsticky(3)
STANDARDS
The feclearexcept(), fegetexceptflag(), feraiseexcept(),
fesetexceptflag(), and fetestexcept() routines conform to ISO/IEC
9899:1999 ("ISO C99").
HISTORY
These functions first appeared in FreeBSD 5.3.
FreeBSD 14.0-RELEASE-p11 May 8, 2004 FreeBSD 14.0-RELEASE-p11