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 .

IEEE/The Open Group                                   2017                                        REMQUO(3POSIX)