HP-UX Reference (11i v1 05/09) - 3 Library Functions A-M (vol 6)

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fetestexcept(3M) fetestexcept(3M)

NAME

fetestexcept() - test ﬂoating-point exceptions

SYNOPSIS

#include <fenv.h>

int fetestexcept(int excepts);

DESCRIPTION

The fetestexcept()

function determines which of a speciﬁed subset of the exception ﬂags are

currently set. The excepts argument speciﬁes the exception ﬂags to be queried. The argument can be con-

structed 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 exceptions.

The ISO/ANSI C committee has approved the

fetestexcept()

function for inclusion in the C9X draft

standard.

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>. 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

The

fetestexcept() function returns the bitwise OR of the exception macros corresponding to the

currently set exceptions included in excepts.

ERRORS

No errors are deﬁned.

EXAMPLE

Call

f() if invalid is set, then g() if overﬂow is set:

#include <fenv.h>

/*...*/

int set_excepts;

/* operations that may raise exceptions */

set_excepts = fetestexcept(FE_INVALID | FE_OVERFLOW);

if (set_excepts & FE_INVALID) f();

if (set_excepts & FE_OVERFLOW) g();