fixmul - Man Page

#include <allegro.h>

fixed fixmul(fixed x, fixed y);

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);

Returns the clamped result of multiplying `x' by `y', setting `errno' to ERANGE if there was an overflow.

fixadd(3), fixsub(3), fixdiv(3), ex3buf(3), excustom(3), exfixed(3), exspline(3), exstars(3), exupdate(3)

ex3buf(3), excustom(3), exfixed(3), exspline(3), exstars(3), exupdate(3), fixadd(3), fixdiv(3), fixsub(3), fixtorad_r(3), radtofix_r(3).