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).
       ┌──────────────────────────┬───────────────┬─────────┐
       │ Interface                │ Attribute     │ Value   │
       ├──────────────────────────┼───────────────┼─────────┤
       │ fmod(), fmodf(), fmodl() │ 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  5.10  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)