REMQUO(3P) POSIX Programmer's Manual REMQUO(3P)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.1‐2008
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 implemen‐
tation-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 ALSOfeclearexcept(), fetestexcept(), remainder()
The Base Definitions volume of POSIX.1‐2008, Section 4.19, 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, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 REMQUO(3P)
