fixmul

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), exstars(3alleg4),
       exupdate(3alleg4)



Allegro                           version 4.4.3                  fixmul(3alleg4)