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remainder(3) Library Functions Manual remainder(3)
drem, dremf, dreml, remainder, remainderf, remainderl - floating-
point remainder function
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);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
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).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│ drem(), dremf(), dreml(), │ Thread safety │ MT-Safe │
│ remainder(), remainderf(), │ │ │
│ remainderl() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘
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)
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user-space interface documentation) project. Information about
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Linux man-pages 6.15 2025-05-17 remainder(3)
Pages that refer to this page: div(3), fma(3), fmod(3), remquo(3)