| NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | BUGS | EXAMPLES | SEE ALSO | COLOPHON | |
|  | 
remainder(3)             Library Functions Manual            remainder(3)
       drem, dremf, dreml, remainder, remainderf, remainderl - floating-
       point remainder function
       Math library (libm, -lm)
       #include <math.h>
       double remainder(double x, double y);
       float remainderf(float x, float y);
       long double remainderl(long double x, long double y);
       /* Obsolete synonyms */
       [[deprecated]] double drem(double x, double y);
       [[deprecated]] float dremf(float x, float y);
       [[deprecated]] long double dreml(long double x, long double y);
   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):
       remainder():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || _XOPEN_SOURCE >= 500
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       remainderf(), remainderl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       drem(), dremf(), dreml():
           /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_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 even.
       These functions are unaffected by the current rounding mode (see
       fenv(3)).
       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 returned.
       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
              errno is set to EDOM (but see BUGS).  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
       attributes(7).
       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                            │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │ drem(), dremf(), dreml(),            │ Thread safety │ MT-Safe │
       │ remainder(), remainderf(),           │               │         │
       │ remainderl()                         │               │         │
       └──────────────────────────────────────┴───────────────┴─────────┘
       remainder()
       remainderf()
       remainderl()
              C11, POSIX.1-2008.
       drem()
       dremf()
       dreml()
              None.
       remainder()
       remainderf()
       remainderl()
              C99, POSIX.1-2001.
       drem() 4.3BSD.
       dremf()
       dreml()
              Tru64, glibc2.
       Before glibc 2.15, the call
           remainder(nan(""), 0);
       returned a NaN, as expected, but wrongly caused a domain error.
       Since glibc 2.15, a silent NaN (i.e., no domain error) is
       returned.
       Before glibc 2.15, errno was not set to EDOM for the domain error
       that occurs when x is an infinity and y is not a NaN.
       The call "remainder(29.0, 3.0)" returns -1.
       div(3), fmod(3), remquo(3)
       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.15.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2025-08-11.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org
Linux man-pages 6.15            2025-05-17                   remainder(3)
Pages that refer to this page: div(3), fma(3), fmod(3), remquo(3)