<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 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