**fmod**

**FMOD(3)** Linux Programmer's Manual **FMOD(3)**
NAME
fmod, fmodf, fmodl - floating-point 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 floating-point 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 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.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
**tributes(7)**.
+-------------------------+---------------+---------+
|Interface | Attribute | Value |
+-------------------------+---------------+---------+
|fmod(), fmodf(), fmodl() | Thread safety | MT-Safe |
+-------------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
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 5.05 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/.
2017-09-15 **FMOD(3)**

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