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REMAINDER 3M "Jul 12, 2006" "SunOS 5.11" "Mathematical Library Functions"
remainder, remainderf, remainderl - remainder function

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

double remainder(double x, double y);

float remainderf(float x, float y);

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

These functions return the floating point remainder r = x - ny when y is non-zero. The value n is the integral value nearest the exact value x/y. When |n - x/y\|| = \(12, the value n is chosen to be even.

The behavior of remainder() is independent of the rounding mode.


Upon successful completion, these functions return the floating point remainder r = x - ny when y is non-zero.

If x or y is NaN, a NaN is returned.

If x is infinite or y is 0 and the other is non-NaN, a domain error occurs and a NaN is returned.


These functions will fail if:

Domain Error

The x argument is \(+-Inf, or the y argument is \(+-0 and the other argument is non-NaN. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception is raised. The remainder() function sets errno to EDOM if y argument is 0 or the x argument is positive or negative infinity.


An application wanting to check for error situations can set errno to 0 before calling remainder(). On return, if errno is non-zero, an error has occurred. The remainderf() and remainderl() functions do not set errno.


See attributes(5) for descriptions of the following attributes:

Interface Stability Standard
MT-Level MT-Safe

abs(3C), div(3C), feclearexcept(3M), fetestexcept(3M), attributes(5), standards(5)