_FLT_MAX _FLT_MIN _M_1_PI _M_1_SQRPI _M_2_PI _M_2_SQRTPI _M_2PI _M_D2R _M_E _M_LN10 _M_LN2 _M_LOG10E _M_LOG2E _M_PI _M_PI_2 _M_PI_3 _M_PI_4 _M_PI_6 _M_R2D _M_SQRT1_2 _M_SQRT2 _MGZERO _SIZE_T isnan mgCopy mgEquals mgHypot mgIsZero mgMax mgMin mgRound mgSquare mgSwap size_t

_M_D2R const float _M_D2R = 0.0174532925199432957692369076848861271344287188854173f 度到弧度的转换常数，PI/180