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);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 500 || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
/* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions compute the remainder of dividing
y. The return value is
n is the value
x / y, rounded to the nearest integer.
If the absolute value of
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,
y. If the return value is 0, it has the
y is a NaN, a NaN is returned.
x is an infinity, and
y is not a NaN, a domain
error occurs, and a NaN is returned.
y is zero, and
x is not a NaN, a domain error
occurs, and a NaN is returned.
The call "remainder(29.0, 3.0)" returns -1.
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
xis an infinity and
yis not a NaN
errno is set to EDOM (but see BUGS). An
invalid floating-point exception (FE_INVALID) is
These functions do not set
errno for this case.
errno is set to EDOM. An invalid
floating-point exception (FE_INVALID) is raised.
The function drem() is from 4.3BSD. The
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
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
is an infinity and
y is not a NaN.
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