Name
fmod, fmodf, fmodl - floating-point remainder functionLibrary
Math library ( libm ", " -lm )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 );
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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Description
These functions compute the floating-point remainder of dividing x byy
. 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 integern
, 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 |
T} | Thread safety | MT-Safe |
Standards
C11, POSIX.1-2008.History
C99, POSIX.1-2001.The variant returning double also conforms to SVr4, 4.3BSD, C89.
Bugs
Before glibc 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred for an infinitex
. See Also
- remainder(3)