float.h

微软的基于HMM的人脸识别原代码, 非常经典的说

#ifndef _FLOATH
#define _FLOATH

#pragma push_safeptr


typedef union {
    unsigned short _Usv[4];
    float _Fv;
    double _Dv;
} _Dv_t;


#define FLT_ROUNDS	1
#define FLT_RADIX	2

#define FLT_DIG		6
#define FLT_EPSILON	1.19209289550781250000e-07
#define FLT_MANT_DIG	24
#define FLT_MAX		3.40282346638528860000e+38
#define FLT_MAX_10_EXP	38
#define FLT_MAX_EXP	128
#define FLT_MIN		1.17549435082228750000e-38
#define FLT_MIN_10_EXP	-37
#define FLT_MIN_EXP	-125

#define DBL_DIG		15
#define DBL_EPSILON	2.22044604925031310000e-16
#define DBL_MANT_DIG	53
#define DBL_MAX		1.79769313486231570000e+308
#define DBL_MAX_10_EXP	308
#define DBL_MAX_EXP	1024
#define DBL_MIN		2.22507385850720140000e-308
#define DBL_MIN_10_EXP	-307
#define DBL_MIN_EXP	-1021

#define LDBL_MANT_DIG	DBL_MANT_DIG
#define LDBL_EPSILON	DBL_EPSILON
#define LDBL_DIG	DBL_DIG
#define LDBL_MIN_EXP	DBL_MIN_EXP
#define LDBL_MIN	DBL_MIN
#define LDBL_MIN_10_EXP	DBL_MIN_10_EXP
#define LDBL_MAX_EXP	DBL_MAX_EXP
#define LDBL_MAX	DBL_MAX
#define LDBL_MAX_10_EXP	DBL_MAX_10_EXP

#pragma pop_ptr

#endif /* _FLOATH */