
FMOD(3) Linux Programmer's Manual FMOD(3)
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():
_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 600  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or cc std=c99
DESCRIPTION
The fmod() function computes 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.
CONFORMING TO
C99, POSIX.12001. 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 manpages project. A description of the
project, and information about reporting bugs, can be found at
http://www.kernel.org/doc/manpages/.
20120315 FMOD(3) 
