cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ] #include <mathcw.h> #include <paircw.h> extern void patan2f (float_pair result, const float_pair x, const float_pair y); extern void patan2 (double_pair result, const double_pair x, const double_pair y); extern void patan2l (long_double_pair result, const long_double_pair x, const long_double_pair y); extern void patan2w (__float80_pair result, const __float80_pair x, const __float80_pair y); extern void patan2q (__float128_pair result, const __float128_pair x, const __float128_pair y); extern void patan2ll (long_long_double_pair result, const long_long_double_pair x, const long_long_double_pair y); extern void patan2df (decimal_float_pair result, const decimal_float_pair x, const decimal_float_pair y); extern void patan2d (decimal_double_pair result, const decimal_double_pair x, const decimal_double_pair y); extern void patan2dl (decimal_long_double_pair result, const decimal_long_double_pair x, const decimal_long_double_pair y); extern void patan2dll (decimal_long_long_double_pair result, const decimal_long_long_double_pair x, const decimal_long_long_double_pair y);
NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.
Special cases for negative zero are:
These also apply when the second argument is zero.atan2(+0,pos) = +0 atan2(-0,pos) = -0 atan2(+0,neg) = +pi atan2(-0,neg) = -pi