fixadd

fixadd(3alleg4)                  Allegro manual                  fixadd(3alleg4)



NAME
       fixadd - Safe function to add fixed point numbers clamping overflow.
       Allegro game programming library.

SYNOPSIS
       #include <allegro.h>


       fixed fixadd(fixed x, fixed y);

DESCRIPTION
       Although fixed point numbers can be added with the normal '+' integer
       operator, that doesn't provide any protection against overflow. If
       overflow is a problem, you should use this function instead. It is slower
       than using integer operators, but if an overflow occurs it will set
       `errno' and clamp the result, rather than just letting it wrap. Example:

          fixed result;
          /* This will put 5035 into `result'. */
          result = fixadd(itofix(5000), itofix(35));
          /* Sets `errno' and puts -32768 into `result'. */
          result = fixadd(itofix(-31000), itofix(-3000));
          ASSERT(!errno); /* This will fail. */

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


SEE ALSO
       fixsub(3alleg4), fixmul(3alleg4), fixdiv(3alleg4)



Allegro                           version 4.4.3                  fixadd(3alleg4)