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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(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
       || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

       The fmod() function computes 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 towards 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
              An invalid floating-point exception (FE_INVALID) is raised.

              These functions do not set errno for this case.

       Domain error: y is zero
              errno  is  set  to  EDOM.   An  invalid floating-point exception
              (FE_INVALID) is raised.

CONFORMING TO

       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4,
       4.3BSD, C89.

SEE ALSO

       remainder(3)

COLOPHON

       This  page  is  part of release 3.24 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

                                  2008-08-05                           FMOD(3)