freebsd man page for fegetenv

FEGETENV(3)						   BSD Library Functions Manual 					       FEGETENV(3)

NAME
     fegetenv, feholdexcept, fesetenv, feupdateenv -- floating-point environment save and restore

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <fenv.h>
     #pragma STDC FENV_ACCESS ON

     int
     fegetenv(fenv_t *envp);

     int
     feholdexcept(fenv_t *envp);

     int
     fesetenv(const fenv_t *envp);

     int
     feupdateenv(const fenv_t *envp);

DESCRIPTION
     The floating-point environment includes exception flags and masks, the current rounding mode, and other architecture-specific settings.  How-
     ever, it does not include the floating-point register file.

     The fegetenv() function stores the current floating-point environment in the object pointed to by envp, whereas feholdexcept() saves the cur-
     rent environment, then clears all exception flags and masks all floating-point exceptions.

     The fesetenv() function restores a previously saved environment.  The feupdateenv() function restores a saved environment as well, but it
     also raises any exceptions that were set in the environment it replaces.

     The feholdexcept() function is often used with feupdateenv() or fesetenv() to suppress spurious exceptions that occur as a result of interme-
     diate computations.  An example in fenv(3) demonstrates how to do this.

RETURN VALUES
     The fegetenv(), feholdexcept(), fesetenv(), and feupdateenv() functions return 0 if they succeed, and non-zero otherwise.

SEE ALSO
     feclearexcept(3), fenv(3), feraiseexcept(3), fesetenv(3), fetestexcept(3), fpgetmask(3), fpgetprec(3), fpsetmask(3), fpsetprec(3)

STANDARDS
     The fegetenv(), feholdexcept(), fesetenv(), and feupdateenv() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY
     These routines first appeared in FreeBSD 5.3.

BSD
								    May 8, 2004 							       BSD