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$FreeBSD: src/lib/msun/man/fegetenv.3,v 1.1 2004/06/06 10:06:26 das Exp $
.Dd May 8, 2004 .Dt FEGETENV 3 .Os .Sh NAME .Nm fegetenv , .Nm feholdexcept , .Nm fesetenv , .Nm feupdateenv .Nd floating-point environment save and restore .Sh LIBRARY .Lb libm .Sh SYNOPSIS n fenv.h .Fd "#pragma STDC FENV_ACCESS ON" .Ft int .Fn fegetenv "fenv_t *envp" .Ft int .Fn feholdexcept "fenv_t *envp" .Ft int .Fn fesetenv "const fenv_t *envp" .Ft int .Fn feupdateenv "const fenv_t *envp" .Sh DESCRIPTION The floating-point environment includes exception flags and masks, the current rounding mode, and other architecture-specific settings. However, it does not include the floating-point register file.
p The .Fn fegetenv function stores the current floating-point environment in the object pointed to by .Fa envp , whereas .Fn feholdexcept saves the current environment, then clears all exception flags and masks all floating-point exceptions.
p The .Fn fesetenv function restores a previously saved environment. The .Fn feupdateenv function restores a saved environment as well, but it also raises any exceptions that were set in the environment it replaces.
p The .Fn feholdexcept function is often used with .Fn feupdateenv or .Fn fesetenv to suppress spurious exceptions that occur as a result of intermediate computations. An example in .Xr fenv 3 demonstrates how to do this. .Sh RETURN VALUES The .Fn fegetenv , .Fn feholdexcept , .Fn fesetenv , and .Fn feupdateenv functions return 0 if they succeed, and non-zero otherwise. .Sh SEE ALSO .Xr feclearexcept 3 , .Xr fenv 3 , .Xr feraiseexcept 3 , .Xr fesetenv 3 , .Xr fetestexcept 3 , .Xr fpgetmask 3 , .Xr fpgetprec 3 , .Xr fpsetmask 3 , .Xr fpsetprec 3 .Sh STANDARDS The .Fn fegetenv , .Fn feholdexcept , .Fn fesetenv , and .Fn feupdateenv functions conform to .St -isoC-99 . .Sh HISTORY These routines first appeared in .Fx 5.3 .
