HP-UX Reference (11i v2 07/12) - 3 Library Functions A-M (vol 6)

f
feclearexcept(3M) feclearexcept(3M)
NAME
feclearexcept( ) - clear floating-point exception flags
SYNOPSIS
#include <fenv.h>
Itanium(R)-based System Only
int feclearexcept(int excepts);
PA-RISC Only
void feclearexcept(int excepts);
DESCRIPTION
The feclearexcept()
function clears the exception flags represented by its argument. The argument
can be constructed as a bitwise OR of the exception macros:
FE_INEXACT , FE_DIVBYZERO ,
FE_UNDERFLOW , FE_OVERFLOW , and FE_INVALID.
FE_ALL_EXCEPT represents all the floating-
point exceptions.
USAGE
To use this function, compile either with the default
-Ae option or with the
-Aa and -D_HPUX_SOURCE
options. Make sure your program includes <fenv.h>.
For Itanium-based systems, specify
+Ofenvaccess on the compiler command line or place the call to
this function under the effect of an affirmative
FENV_ACCESS pragma:
#pragma STDC FENV_ACCESS ON
If the FENV_ACCESS pragma is placed outside of any top-level declarations in a file, the pragma will
apply to all declarations in the compilation following the pragma until another FENV_ACCESS pragma is
encountered or until the end of the file is reached.
If the FENV_ACCESS pragma is placed at the beginning of a block (compound statement), the pragma will
apply until another FENV_ACCESS pragma is encountered or until the end of the block is reached.
For PA-RISC, you might need to use the +Onomoveflops compiler option in order to prevent optimizations
that can undermine the specified behavior of this function.
Link in the math library by specifying -lm on the compiler or linker command line.
For more information, see the HP-UX Floating-Point Guide.
RETURN VALUE
Itanium-based System Only
This function always returns 0, indicating all specified exceptions were cleared.
PA-RISC Only
None.
ERRORS
No errors are defined.
EXAMPLES
Clear the underflow and inexact floating-point exception flags:
#include <fenv.h>
/*...*/
feclearexcept(FE_UNDERFLOW | FE_INEXACT);
Clear all floating-point exception flags:
#include <fenv.h>
/*...*/
feclearexcept(FE_ALL_EXCEPT);
SEE ALSO
fegetexceptflag(3M), fegettrapenable(3M), feraiseexcept(3M), fesetexceptflag(3M), fesettrapenable(3M),
fetestexcept(3M), fenv(5).
394 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: December 2007 Update