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al_fixsub(3) Library Functions Manual al_fixsub(3) NAME al_fixsub - Allegro 5 API SYNOPSIS #include <allegro5/allegro.h> al_fixed al_fixsub(al_fixed x, al_fixed y); DESCRIPTION Although fixed point numbers can be subtracted with the normal - inte- ger 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 Allegro's errno and clamp the result, rather than just letting it wrap. Example: al_fixed result; /* This will put 4965 into `result'. */ result = al_fixsub(al_itofix(5000), al_itofix(35)); /* Sets errno and puts -32768 into `result'. */ result = al_fixsub(al_itofix(-31000), al_itofix(3000)); assert(!al_get_errno()); /* This will fail. */ RETURN VALUE Returns the clamped result of subtracting y from x, setting Allegro's errno to ERANGE if there was an overflow. SEE ALSO al_fixadd(3), al_fixmul(3), al_fixdiv(3), al_get_errno(3). Allegro reference manual al_fixsub(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO
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