[fpc-devel] bug: Inc(v,i)/Dec(v,i)

Gerhard Scholz gs at g--s.de
Tue Jul 5 13:53:46 CEST 2005

> Bug 4152 is partly fixed. The compiletime error is removed. Only the
> runtime overflow is left. That still needs to be decided how to handle it.
> The following code also fails with an overflow
> {$Q+}
> var
>   v : cardinal;
> begin
>   v:=100;
>   inc(v,-1);
> end.
> The reason is that -1 is in fact an addition of $ffffffff resulting in the
> carry flag being set and therefor an overflow.

Maybe the cleanest way is (in the $r+ $q+ mode) to handle 
    inc ( v, d ) ;
the same as 
   v := v + d ;

I replaced my code like this when I found the bug, and now my code works.


More information about the fpc-devel mailing list