FMOD
Section: Linux Programmer's Manual (3)
Updated: 20170915
Page Index
NAME
fmod, fmodf, fmodl  floatingpoint remainder function
SYNOPSIS
#include <math.h>
double fmod(double x, double y);
float fmodf(float x, float y);
long double fmodl(long double x, long double y);
Link with lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
fmodf(),
fmodl():

_ISOC99_SOURCE  _POSIX_C_SOURCE >= 200112L
 /* Since glibc 2.19: */ _DEFAULT_SOURCE
 /* Glibc versions <= 2.19: */ _BSD_SOURCE  _SVID_SOURCE
DESCRIPTION
These functions compute the floatingpoint remainder of dividing
x
by
y.
The return value is
x

n
*
y,
where
n
is the quotient of
x
/
y,
rounded toward 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 floatingpoint exception
(FE_INVALID)
is raised.
 Domain error: y is zero

errno
is set to
EDOM.
An invalid floatingpoint exception
(FE_INVALID)
is raised.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
Interface  Attribute  Value

fmod(),
fmodf(),
fmodl()
 Thread safety  MTSafe

CONFORMING TO
C99, POSIX.12001, POSIX.12008.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.
BUGS
Before version 2.10, the glibc implementation did not set
errno
to
EDOM
when a domain error occurred for an infinite
x.
SEE ALSO
remainder(3)
COLOPHON
This page is part of release 5.10 of the Linux
manpages
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/manpages/.