<fenv.h> floating-point environment access in C99
The C99 standard header file <fenv.h>
provides access to an IEEE 754-compliant floating-point environment for numerical programming.
The library introduces two types and numerous macros and functions for managing and controlling floating-point state.
The new types supported are:
fenv_t
, representing the entire floating-point environment.fexcept_t
, representing the floating-point state.
New macros supported include:
FE_DIVBYZERO
,FE_INEXACT
,FE_INVALID
,FE_OVERFLOW
andFE_UNDERFLOW
for managing floating-point exceptions.FE_DOWNWARD
,FE_TONEAREST
,FE_TOWARDZERO
,FE_UPWARD
for managing rounding in the represented rounding direction.FE_DFL_ENV
, representing the default floating-point environment.
New functions include:
int feclearexcept(int ex); // clear floating-point exceptions selected by ex int feraiseexcept(int ex); // raise floating point exceptions selected by ex int fetestexcept(int ex); // test floating point exceptions selected by ex int fegetround(void); // return the current rounding mode int fesetround(int mode); // set the current rounding mode given by mode int fegetenv(fenv_t *penv); return the floating-point environment in penv int fesetenv(const fenv_t *penv); // set the floating-point environment to penv