FMOD(3)                    Linux Programmer's Manual                   FMOD(3)



NAME
       fmod, fmodf, fmodl - floating-point 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():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 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).

       allbox;  lbw24  lb  lb  l  l  l.   Interface Attribute Value T{ fmod(),
       fmodf(), fmodl() T}   Thread safety  MT-Safe

CONFORMING TO
       C99, POSIX.1-2001, POSIX.1-2008.

       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 4.16 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.



                                  2017-09-15                           FMOD(3)