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)