PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       remquo, remquof, remquol — remainder functions

SYNOPSIS

       #include <math.h>

       double remquo(double x, double y, int *quo);
       float remquof(float x, float y, int *quo);
       long double remquol(long double x, long double y, int *quo);

DESCRIPTION

       The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2017 defers to the ISO C standard.

       The  remquo(),  remquof(), and remquol() functions shall compute the same remainder as the
       remainder(), remainderf(), and remainderl() functions, respectively. In the object pointed
       to  by  quo,  they  store  a  value  whose  sign is the sign of x/y and whose magnitude is
       congruent modulo 2n to the magnitude of the integral  quotient  of  x/y,  where  n  is  an
       implementation-defined  integer greater than or equal to 3. If y is zero, the value stored
       in the object pointed to by quo is unspecified.

       An application wishing to check for error situations should set errno  to  zero  and  call
       feclearexcept(FE_ALL_EXCEPT)  before  calling these functions. On return, if errno is non-
       zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is  non-zero,
       an error has occurred.

RETURN VALUE

       These functions shall return x REM y.

       On  systems  that  do not support the IEC 60559 Floating-Point option, if y is zero, it is
       implementation-defined whether a domain error occurs or zero is returned.

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

       If x is ±Inf or y is zero and the other argument is non-NaN, a domain error  shall  occur,
       and a NaN shall be returned.

ERRORS

       These functions shall fail if:

       Domain Error
                   The x argument is ±Inf, or the y argument is ±0 and the other argument is non-
                   NaN.

                   If the integer expression (math_errhandling & MATH_ERRNO)  is  non-zero,  then
                   errno  shall  be set to [EDOM].  If the integer expression (math_errhandling &
                   MATH_ERREXCEPT) is non-zero, then the invalid floating-point  exception  shall
                   be raised.

       These functions may fail if:

       Domain Error
                   The y argument is zero.

                   If  the  integer  expression (math_errhandling & MATH_ERRNO) is non-zero, then
                   errno shall be set to [EDOM].  If the integer expression  (math_errhandling  &
                   MATH_ERREXCEPT)  is  non-zero, then the invalid floating-point exception shall
                   be raised.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       On  error,  the  expressions  (math_errhandling  &  MATH_ERRNO)  and  (math_errhandling  &
       MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.

RATIONALE

       These  functions are intended for implementing argument reductions which can exploit a few
       low-order bits of the quotient. Note that x may be so large in  magnitude  relative  to  y
       that an exact representation of the quotient is not practical.

FUTURE DIRECTIONS

       None.

SEE ALSO

       feclearexcept(), fetestexcept(), remainder()

       The  Base  Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of Error Conditions
       for Mathematical Functions, <math.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  by
       the  Institute  of  Electrical  and Electronics Engineers, Inc and The Open Group.  In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .