NAME

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

LIBRARY

       Math library (libm, -lm)

SYNOPSIS

       #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

DESCRIPTION

       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.

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  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.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ drem(), dremf(), dreml(), remainder(), remainderf(), remainderl()           │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       remainder()
       remainderf()
       remainderl()
              C11, POSIX.1-2008.

       drem()
       dremf()
       dreml()
              None.

HISTORY

       remainder()
       remainderf()
       remainderl()
              C99, POSIX.1-2001.

       drem() 4.3BSD.

       dremf()
       dreml()
              Tru64, glibc2.

BUGS

       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.

EXAMPLES

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

SEE ALSO

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

Linux man-pages 6.7                                2023-10-31                                       remainder(3)