fixmul(3alleg4) Allegro manual fixmul(3alleg4)
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(3alleg4), fixsub(3alleg4), fixdiv(3alleg4), ex3buf(3alleg4), excustom(3alleg4), exfixed(3alleg4), exspline(3alleg4), exs-
tars(3alleg4), exupdate(3alleg4)
Allegro version 4.4.2 fixmul(3alleg4)
