Re: Newbie question: getting an object back from just a pointer
Re: Newbie question: getting an object back from just a pointer
- Subject: Re: Newbie question: getting an object back from just a pointer
- From: Keary Suska <email@hidden>
- Date: Sat, 24 Feb 2007 11:36:34 -0700
- Thread-topic: Newbie question: getting an object back from just a pointer
on 2/24/07 5:35 AM, email@hidden purportedly said:
> QTMovie* movie = [QTMovie movieWithURL:url error:&initError];
<snip>
>
> // let's just test that, shall we?
> NSLog (@"SelectorHelper re-casting movie...");
> QTMovie* movieTest = (QTMovie*) &movie;
If the "movie" is the same in both snippets, why are you casting a pointer
to it? I would think movie is already a pointer, or there is something more
seriously wrong. Instead you probably want (note no ampersand):
QTMovie* movieTest = (QTMovie*) movie;
You may, in several places, be making a common "newbie" (or Java programmer
;-) mistake of not treating objects as pointers. This piece:
NSLog (@"Created QTMovie %@ at address %u", movie, &movie);
Is also wrong, at least in the extent that if you want output of movie's
pointer value, you would simply:
NSLog (@"Created QTMovie %@ at address %p", movie, (void *)movie);
The void * shouldn't be necessary, but it may make what you are doing
explicit.
Finally, in C, & means make-pointer-to and * means dereference-pointer.
Best,
Keary Suska
Esoteritech, Inc.
"Demystifying technology for your home or business"
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden