HP-UX Reference (11i v1 00/12) - 3 Library Functions A-M (vol 6)

ManualsBrandsHP ManualsSoftwareHP-UX Reference Manuals

261

262

263

264

265

266

267

268

269

270

__________________________________________________________________________________________________________________________________________________________________________________________________

STANDARD Printed by: Nora Chuang [nchuang] STANDARD

/build/1111/BRICK/man3/!!!intro.3c

________________________________________________________________

___ ___

feholdexcept(3M) feholdexcept(3M)

NAME

feholdexcept() - save ﬂoating-point environment

SYNOPSIS

#include <fenv.h>

int feholdexcept(fenv_t *envp);

DESCRIPTION

The feholdexcept() function saves the current ﬂoating-point environment in the object pointed to by

the argument envp, clears the exception ﬂags, and disablesall traps.

Use feholdexcept() with feupdateenv() to hide spurious exceptions. Use it with fesetenv()

to hide all exceptions.

The ISO/ANSI C committee has approved the feholdexcept() 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

feholdexcept() function returns a zero value, indicating the successful disablingof any traps.

ERRORS

No errors are deﬁned.

EXAMPLE

Store the current ﬂoating-point environment in

holdenv, hide spurious underﬂow exceptions, and con-

tinue on any exceptions that occur until the call to feupdateenv()

is encountered.

#include <fenv.h>

/*...*/

fenv_t holdenv;

feholdexcept(&holdenv);

/* perform operations */

if (/* test for spurious underflow */)

feclearexcept(FE_UNDERFLOW);

feupdateenv(&holdenv); /* raise accumulated exceptions */