Header File 

fastmath.h  

Category 

Math Routines 

Description 

The FastMath routines are high performance math routines that don't check for most error conditions and never call matherr. They are coded for maximum speed. These functions are never exported from the RTLDLL, which means that they always get linked directly into the PE file that is being created. 

When you include fastmath.h, the following math functions are remapped to these fastmath functions.

If you don't want the standard C function names remapped to the FastMath versions, then define _FM_NO_REMAP. The FastMath routines can still be called with their _fm_xxx names. 

The following additional functions are available in FastMath; they are not directly supported in the regular RTL: 

void _FMAPI _fm_sincos(double __a, double *__x, double *__y); 

void _FMAPI _fm_sincosl(long double __a, long double *__x, long double *__y); 

long double _FMAPI _fm_atanhl (long double __x); 

long double _FMAPI _fm_acoshl (long double __x); 

long double _FMAPI _fm_asinhl (long double __x); 

__inline void _fm_fwait(void) 

unsigned int _FMAPI _fm_init(void); 

_fm_fwait is a special inline function that performs an intrinsic FWAIT instruction. 

_Fm_init is a function that can be called to mask all fpu exceptions prior to using the FastMath routines.