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

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

SYNOPSIS
       #include 

       /* 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 featuretestmacros(7)):

       remainder():
           SVIDSOURCE || BSDSOURCE || XOPENSOURCE >= 500 ||
           XOPENSOURCE && XOPENSOURCEEXTENDED || ISOC99SOURCE ||
           POSIXCSOURCE >= 200112L;
           or cc -std=c99
       remainderf(), remainderl():
           BSDSOURCE || SVIDSOURCE || XOPENSOURCE >= 600 ||
           ISOC99SOURCE || POSIXCSOURCE >= 200112L;
           or cc -std=c99
       drem(), dremf(), dreml():
           SVIDSOURCE || BSDSOURCE

DESCRIPTION
       The  remainder()  function  computes  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 even.

       These functions are  unaffected  by  the  current  rounding  mode  (see
       fenv(3)).

       The drem() function does precisely the same thing.

RETURN VALUE
       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
       returned.

ERRORS
       See matherror(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 (FEINVALID) 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
              (FEINVALID) is raised.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       ┌───────────────────────────┬───────────────┬─────────┐
       │Interface                  │ Attribute     │ Value   │
       ├───────────────────────────┼───────────────┼─────────┤
       │drem(), dremf(), dreml(),  │ Thread safety │ MT-Safe │
       │remainder(), remainderf(), │               │         │
       │remainderl()               │               │         │
       └───────────────────────────┴───────────────┴─────────┘
CONFORMING TO
       The functions remainder(), remainderf(), and remainderl() are specified
       in C99 and POSIX.1-2001.

       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.

BUGS
       The call

           remainder(nan(""), 0);

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

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

SEE ALSO
       div(3), fmod(3), remquo(3)

COLOPHON
       This  page  is  part of release 3.53 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/.



                                  2010-09-20                      REMAINDER(3)