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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | BUGS | EXAMPLES | SEE ALSO | COLOPHON |
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REMAINDER(3) Linux Programmer's Manual REMAINDER(3)
drem, dremf, dreml, remainder, remainderf, remainderl - floating-
point remainder function
#include <math.h>
/* The C99 versions */
double remainder(double x, double y);
float remainderf(float x, float y);
long double remainderl(long double x, long double y);
/* Obsolete synonyms */
double drem(double x, double y);
float dremf(float x, float y);
long double dreml(long double x, long double y);
Link with -lm.
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() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘
The functions remainder(), remainderf(), and remainderl() are
specified in C99, POSIX.1-2001, and POSIX.1-2008.
The function drem() is from 4.3BSD. The float and long double
variants dremf() and dreml() exist on some systems, such as Tru64
and glibc2. Avoid the use of these functions in favor of
remainder() etc.
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)
This page is part of release 5.13 of the Linux man-pages project.
A description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2021-03-22 REMAINDER(3)
Pages that refer to this page: div(3), fma(3), fmod(3), remquo(3)
Copyright and license for this manual page
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