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:

New macros supported include:

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 x
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