cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ] #include <mathcw.h> extern float atan2pf (float y, float x); extern double atan2p (double y, double x); extern long double atan2pl (long double y, long double x); extern __float80 atan2pw (__float80 y, __float80 x); extern __float128 atan2pq (__float128 y, __float128 x); extern long_long_double atan2pll (long_long_double y, long_long_double x); extern decimal_float atan2pdf (decimal_float y, decimal_float x); extern decimal_double atan2pd (decimal_double y, decimal_double x); extern decimal_long_double atan2pdl (decimal_long_double y, decimal_long_double x); extern decimal_long_long_double atan2pdll (decimal_long_long_double y, decimal_long_long_double x);
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.atan2p(+0,pos) = +0 atan2p(-0,pos) = -0 atan2p(+0,neg) = +pi atan2p(-0,neg) = -pi