# FMOD

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

ATTRIBUTES

CONFORMING TO

BUGS

SEE ALSO

COLOPHON

## 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**():

_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 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
**attributes**(7).

## CONFORMING TO

C99,
POSIX.1-2001. 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 3.53 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/.