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FEGETENV(3) Library Functions Manual FEGETENV(3) NAME fegetenv, feholdexcept, fesetenv, feupdateenv -- floating-point envi- ronment 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 float- ing-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 re- places. The feholdexcept() function is often used with feupdateenv() or fesetenv() to suppress spurious exceptions that occur as a result of intermediate 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. FreeBSD 15.0 May 8, 2004 FEGETENV(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | STANDARDS | HISTORY
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