NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | BUGS | SEE ALSO |
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fmod(3) Library Functions Manual fmod(3)
fmod, fmodf, fmodl - floating-point remainder function
Math library (libm, -lm)
#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
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.
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.
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.
For an explanation of the terms used in this section, see attributes(7). ┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────────────────────────────────┼───────────────┼─────────┤ │fmod(), fmodf(), fmodl() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
Before glibc 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred for an infinite x.
remainder(3)
Linux man-pages 6.04 2023-03-30 fmod(3)
Pages that refer to this page: remainder(3), remquo(3)