fixmul(3) Allegro manual fixmul(3)
NAME
fixmul - Multiplies two fixed point values together. Allegro game
programming library.
SYNOPSIS
**#include <allegro.h>**
**fixed fixmul(fixed x, fixed y);**
DESCRIPTION
A fixed point value can be multiplied or divided by an integer with the
normal `*' and `/' operators. To multiply two fixed point values, though,
you must use this function.
If an overflow occurs, `errno' will be set and the maximum possible value
will be returned, but `errno' is not cleared if the operation is
successful. This means that if you are going to test for overflow you
should set `errno=0' before calling fixmul(). Example:
fixed result;
/* This will put 30000 into `result'. */
result = fixmul(itofix(10), itofix(3000));
/* But this overflows, and sets `errno'. */
result = fixmul(itofix(100), itofix(3000));
ASSERT(!errno);
RETURN VALUE
Returns the clamped result of multiplying `x' by `y', setting `errno' to
ERANGE if there was an overflow.
SEE ALSO
fixadd(3), fixsub(3), fixdiv(3), ex3buf(3), excustom(3), exfixed(3),
exspline(3), exstars(3), exupdate(3)
Allegro version 4.4.3 fixmul(3)