_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED ||
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99

remainderf(),
remainderl():

_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99

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

_SVID_SOURCE || _BSD_SOURCE

DESCRIPTION

The
remainder()
function computes 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.

RETURN VALUE

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.

ERRORS

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

An invalid floating-point exception
(FE_INVALID)
is raised.

These functions do not set
errno
for this case.

Domain error: y is zeroerrno

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

CONFORMING TO

The functions
remainder(),
remainderf(),
and
remainderl()
are specified in C99 and POSIX.1-2001.

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.

BUGS

The call

remainder(nan(""), 0);

returns a NaN, as expected, but wrongly causes a domain error;
it should yield a silent NaN.

This page is part of release 3.27 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.