> To give a better picture of my problem:
>
> Type
> tQSDL_Surface
> = Class (SomeClass)
> Protected
> fFlags : UInt32; {LongWord}
>
> Function GetFlag(aBit: UInt32): Boolean;
> Function SetFlag(aBig: UInt32; aBool: Boolean);
>
> Public
> Constructor Create();
> Destructor Destroy();
>
> Property HWSurface : Boolean Index SDL_HWSurface
> Read GetFlag
> Write SetFlag;
> Property SRCAlpha : Boolean Index SDL_SrcAlpha
> Read GetFlag
> Write SetFlag;
> end;
>
> SDL_HWSurface and SDL_SRCAlpha are constants defined in the SDL_Video
> unit. They are meant for Boolean operations. More specificly they are
> meant to be ORed togeather to create a flag list and ANDed with fFlags
> to check for there state.
>
> I'm trying to do two things with these properties:
> 1# Not force a programmer to include the SDL Unit to get these
> constants.
> 2# Improve the readability of my code by using these properties to
> control flags.
>
> For instance a child object, SDL_VideoSurface, would have extra flags
> such as FullScreen. Calling the following:
>
> MyVideoSurface.FullScreen := TRUE;
>
> would cause the fullscreen bit to be set to true and when the screen is
> allocated it will fill the entire screen. The Problem is that if I
> define a constant index {$Mode ObjFPC} requires that index to be an
> Signed Integer value which it cannot be because that would change its
> binary value and the bitwise operations would be based on the wrong
> values.
>
> My solution is to simply create methods for each flag individualy that
> calls GetFlag/SetFlag with the correct paramaters. I was just wondering
> if there was a way to get around this.
>
> If not, thanks anyways. I just learned something new about indexes and
> and making sure I understand there limitation correctly.
Indexes are forced to 32bit signed, because the index type is not know yet
when the index keyword is parsed.
But i don't see any problems with 32bit signed/unsigned wrt bitwise
operations. The only problem can be range checking.
Which compiler version do you use? If it doesn't work with 1.9.x then
submit a bug with a complete example.
Peter
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