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

DESCRIPTION

The
fmod()
function computes the floating-point remainder of dividing x by
y.
The return value is x - n * y, where n
is the quotient of x / y, rounded towards zero to an integer.

RETURN VALUE

On success, these
functions return the value x - n*y,
for some integer n,
such that the returned value has the same sign as
x
and a magnitude less than the magnitude of
y.

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

If
x
is an infinity,
a domain error occurs, and
a NaN is returned.

If
y
is zero,
a domain error occurs, and
a NaN is returned.

If
x
is +0 (-0), and
y
is not zero, +0 (-0) 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

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

Domain error: y is zero

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

BUGS

Before version 2.10, the glibc implementation did not set
errno
to
EDOM
when a domain error occurred for an infinite
x.

CONFORMING TO

C99, POSIX.1-2001.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.

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/.