fmod (3)
Leading comments
Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
and Copyright 2008, Linux Foundation, written by Michael Kerrisk
<mtk.manpages@gmail.com>
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NAME
fmod, fmodf, fmodl - floating-point remainder functionSYNOPSIS
#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
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 attributes(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.