NAME

fmod, drem, remainder − Compute the floating-point remainder

SYNOPSIS

#include <math.h>
double fmod(
        double x,
        double y ); float fmodf(
        float x,
        float y ); long double fmodl(
        long double x,
        long double y ); double drem(
        double x,
        double y ); float dremf(
        float x,
        float y ); long double dreml(
        long double x,
        long double y ); double remainder(
        double x,
        double y ); float remainderf(
        float x,
        float y ); long double remainderl(
        long double x,
        long double y );

LIBRARY

Math Library (libm)

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

fmod():  XPG4

remainder():  XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

DESCRIPTION

The fmod(), fmodf(), and fmodl() functions return the remainder r = x − n∗y, where n = trunc(x/y). The result has the same sign as x and magnitude less than the magnitude of y. The remainder is computed exactly and |r| is less than |y|. 

The drem(), dremf(), dreml(), remainder(), remainderf(), and remainderl() functions return the remainder r = x − n∗y, where n = rint(x/y).  Additionally, if |n− x/y|=1/2, then n is even.  The remainder is computed exactly and |r| is less than or equal to |y|/2. 

The drem() and remainder() functions are aliases of each other. The dremf(), and remainderf() functions are aliases of each other. The dreml() and remainderl() functions are aliases of each other. 

The following table describes function behavior in response to exceptional arguments: