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 and FE_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