User Tools

Site Tools




fmod, fmodf, fmodl - floating-point remainder value function


c99 [ flag… ] file-lm [ library… ]
#include <math.h>

double fmod(double x, double y);

float fmodf(float x, float y);

long double fmodl(long double x, long double y);


These functions return the floating-point remainder of the division of x by y.


These functions return the value xi * 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, a NaN is returned.

If y is 0, a domain error occurs and a NaN is returned.

If x is infinite, a domain error occurs and a NaN is returned.

If x is ±0 and y is not 0, ±0 is returned.

If x is not infinite and y is ±Inf, x is returned.


These functions will fail if:

Domain Error

The x argument is infinite or y is 0.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the invalid floating-point exception is raised.


An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.


See attributes(7) for descriptions of the following attributes:


math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), isnan(3M), attributes(7), standards(7)

solaris/fmod.3m.txt · Last modified: 2023/07/19 08:58 by A User Not Logged in