remquo
, remquof
–remainder and part of quotient#include <math.h> double remquo(double x, double y, int *quo); float remquof(float x, float y, int *quo);
Description
The remquo
functions compute the same remainder as the remainder
functions; this value is in the range -y/2 ... +y/2. 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
. (That is, quo
is given the n lsbs of the
quotient, not counting the sign.) This implementation uses n=31 if int is 32
bits or more, otherwise, n is 1 less than the width of int.
For example:
remquo(-29.0, 3.0, &quo)
returns -1.0 and sets quo=10, and
remquo(-98307.0, 3.0, &quo)
returns -0.0 and sets quo=-32769, although for 16-bit int, quo=-1. In the latter case, the actual quotient of -(32769=0x8001) is reduced to -1 because of the 15-bit limitation for the quotient.
Returns
When either argument is NaN, NaN is returned. If y is 0 or x is
infinite (and neither is NaN), a domain error occurs (i.e. the "invalid"
floating point exception is raised or errno is set to EDOM), and NaN is
returned.
Otherwise, the remquo
functions return x REM y.
Bugs
IEEE754-2008 calls for remquo
(subnormal, inf) to cause the "underflow"
floating-point exception. This implementation does not.
Portability
C99, POSIX.