cc [ flag ... ] file ... -lm [ library ... ] #include <math.h>double fmod(double x, double y);
The fmod() function returns the value x - i * y, for some integer i such that, if y is non-zero, the result has the same sign as x and magnitude less than the magnitude of y.
If x or y is NaN, NaN is returned. If y is 0, NaN is returned and errno is set to EDOM. If x is ±Inf, NaN is returned. If y is non-zero, fmod(±0,y) returns the value of x. If x is not ±Inf, fmod(x,±Inf) returns the value of x.
Portable applications should not call fmod() with y equal to 0, because the result is implementation-dependent. The application should verify y is non-zero before calling fmod().
An application wishing to check for error situations should set errno to 0 before calling fmod(). If errno is non-zero on return, or the return value is NaN, an error has occurred.
See attributes(5) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|