fmod(3)fmod(3)NAME
fmod, drem, remainder - Compute the floating-point remainderSYNOPSIS
#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 stan‐
dards 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 magni‐
tude less than the magnitude of y. The remainder is computed exactly
and |r| is less than |y|.
The drem(), dremf(), dreml(), remainder(), remainderf(), and remain‐
derl() 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 com‐
puted 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 excep‐
tional arguments:
─────────────────────────────────────────────────────────────────────
Function Exceptional Argu‐ Routine Behavior
ment
─────────────────────────────────────────────────────────────────────
fmod(), fmodf(), fmodl() x = infinity Invalid argument
fmod(), fmodf(), fmodl() y = 0 Invalid argument
drem(), dremf(), dreml() x = infinity Invalid argument
drem(), dremf(), dreml() y = 0 Invalid argument
remainder() x = infinity Invalid argument
remainderf() x = infinity Invalid argument
remainderl() x = infinity Invalid argument
remainder() y = 0 Invalid argument
remainderf() y = 0 Invalid argument
remainderl() y = 0 Invalid argument
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fmod(3)