remainder - Man Page

Math library (libm, -lm)

#include <math.h>

double remainder(double x, double y);
float remainderf(float x, float y);
long double remainderl(long double x, long double y);

/* Obsolete synonyms */
[[deprecated]] double drem(double x, double y);
[[deprecated]] float dremf(float x, float y);
[[deprecated]] long double dreml(long double x, long double y);

remainder():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || _XOPEN_SOURCE >= 500
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

remainderf(), remainderl():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

drem(), dremf(), dreml():

    /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

These functions compute the remainder of dividing x by y. The return value is x-n*y, where n is the value x / y, rounded to the nearest integer. If the absolute value of x-n*y is 0.5, n is chosen to be even.

These functions are unaffected by the current rounding mode (see fenv(3)).

The drem() function does precisely the same thing.

On success, these functions return the floating-point remainder, x-n*y. If the return value is 0, it has the sign of x.

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

If x is an infinity, and y is not a NaN, a domain error occurs, and a NaN is returned.

If y is zero, and x is not a NaN, a domain error occurs, and a NaN is returned.

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x is an infinity and y is not a NaN

errno is set to EDOM (but see Bugs). An invalid floating-point exception (FE_INVALID) is raised.

These functions do not set errno for this case.

Domain error: y is zero

errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.

For an explanation of the terms used in this section, see attributes(7).

remainder()

remainderf()

remainderl()

C11, POSIX.1-2008.

drem()

dremf()

dreml()

None.

remainder()

remainderf()

remainderl()

C99, POSIX.1-2001.

drem()

4.3BSD.

dremf()

dreml()

Tru64, glibc2.

Before glibc 2.15, the call

remainder(nan(""), 0);

returned a NaN, as expected, but wrongly caused a domain error. Since glibc 2.15, a silent NaN (i.e., no domain error) is returned.

Before glibc 2.15, errno was not set to EDOM for the domain error that occurs when x is an infinity and y is not a NaN.

The call "remainder(29.0, 3.0)" returns -1.

div(3), fmod(3), remquo(3)

div(3), fma(3), fmod(3), remquo(3).

The man pages drem(3), dremf(3), dreml(3), remainderf(3) and remainderl(3) are aliases of remainder(3).