REMQUO(3)                  POSIX Programmer's Manual                 REMQUO(3)



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

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 2_n 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(3)
