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

       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. */

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

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

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

Allegro                                           version 4.4.3                                  fixadd(3alleg4)

#include<allegro.h>fixedfixadd(fixedx,fixedy);