table of contents
fmod(3) | Library Functions Manual | fmod(3) |
NAME¶
fmod, fmodf, fmodl - floating-point remainder function
LIBRARY¶
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);
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 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 |
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 infinite x.
SEE ALSO¶
2023-03-30 | Linux man-pages 6.04 |