C Programming/fenv.h

fenv.h is a header file containing various functions and macros for manipulating the floating-point environment.

This header declares two types, fenv_t (represents the whole floating-point environment) and fexcept_t (represents the floating-point status flags). It also declares several feature macros, beginning with FE_ and a capital letter.

Functions

Other than fegetround and fetestexcept, these functions return zero/non-zero on success/failure.

Declaration	Description
int feclearexcept(int excepts);	clear exceptions specified by excepts
int fegetenv(fenv_t *penv);	store current floating-point environment in penv
int fegetexceptflag(fexcept_t *pflag, int excepts);	store current status flags in pflags
int fegetround(void);	retrieve current rounding direction
int feholdexcept(fenv_t *penv);	save current floating-point environment to penv and clear all exceptions
int feraiseexcept(int excepts);	raise floating-point exceptions
int fesetenv(const fenv_t *penv);	set current floating-point environment to penv
int fesetexceptflag(const fexcept_t *pflags, int excepts);	set current status flags to those stored in pflags
int fesetround(int round);	set current rounding direction to round
int fetestexcept(int excepts);	test whether certain exceptions have been raised
int feupdateenv(const fenv_t *penv);	restore floating-point environment penv, but keep current exceptions
int fesetprec(int prec)	Sets the precision mode to the value specified by prec.