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

       drem,  dremf, dreml, remainder, remainderf, remainderl - floating-point
       remainder function

       #include <math.h>

       /* The C99 versions */
       double remainder(double x, double y);
       float remainderf(float x, float y);
       long double remainderl(long double x, long double y);

       /* Obsolete synonyms */
       double drem(double x, double y);
       float dremf(float x, float y);
       long double dreml(long double x, long double y);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

           _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
       remainderf(), remainderl():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
       drem(), dremf(), dreml():
           _SVID_SOURCE || _BSD_SOURCE

       These  functions  compute the remainder of dividing x by y.  The return
       value is x-n*y, where n is the value  x / y,  rounded  to  the  nearest
       integer.   If  the  absolute  value  of x-n*y is 0.5, n is chosen to be

       These functions are  unaffected  by  the  current  rounding  mode  (see

       The drem() function does precisely the same thing.

       On success, these functions return the floating-point remainder, x-n*y.
       If the return value is 0, it has the sign of x.

       If x or y is a NaN, a NaN is returned.

       If x is an infinity, and y is not a NaN, a domain error occurs,  and  a
       NaN is returned.

       If  y  is zero, and x is not a NaN, a domain error occurs, and a NaN is

       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 and y is not a NaN
              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.

       For  an  explanation  of  the  terms  used   in   this   section,   see

       |Interface                  | Attribute     | Value   |
       |drem(), dremf(), dreml(),  | Thread safety | MT-Safe |
       |remainder(), remainderf(), |               |         |
       |remainderl()               |               |         |
       The functions remainder(), remainderf(), and remainderl() are specified
       in C99, POSIX.1-2001, and POSIX.1-2008.

       The function drem() is from 4.3BSD.  The float and long double variants
       dremf()  and  dreml()  exist on some systems, such as Tru64 and glibc2.
       Avoid the use of these functions in favor of remainder() etc.

       The call

           remainder(nan(""), 0);

       returns a NaN, as expected, but  wrongly  causes  a  domain  error;  it
       should yield a silent NaN.

       The call "remainder(29.0, 3.0)" returns -1.

       div(3), fmod(3), remquo(3)

       This  page  is  part of release 4.04 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

                                  2015-04-19                      REMAINDER(3)
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