
REMQUO(P) POSIX Programmer's Manual REMQUO(P)
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 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 con
gruent modulo 2**n to the magnitude of the integral quotient of x/ y, where n is an imple
mentationdefined integer greater than or equal to 3.
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 nonzero,
an error has occurred.
RETURN VALUE
These functions shall return x REM y.
If x or y is NaN, a NaN shall be returned.
If x is +Inf or y is zero and the other argument is nonNaN, a domain error shall occur,
and either a NaN (if supported), or an implementationdefined value 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 nonzero, then errno shall be
set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is nonzero,
then the invalid floatingpoint 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 nonzero.
RATIONALE
These functions are intended for implementing argument reductions which can exploit a few
loworder 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
IEEE Std 1003.12001, Section 4.18, Treatment of Error Conditions for Mathematical Func
tions, <math.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology  Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 20012003 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 orig
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 REMQUO(P) 
