Some things of memory management

[Alec]

Hi. Im just beginner with objective c. I have a some problems with memory management. In here is some example code:
In the same method:
-(void)doSomething{

NSString *strTxt = @"This is txt";
NSString *strTxt2 = @"This is txt2";

NSMutableArray *maAllTxt = [NSMutableArray alloc] initWithObjects:strTxt, strTxt2

[maAllTxt removeObjectAtIndex:0 ];

NSLog(@"%@", strTxt);

}

The question is, when im printing strTxt to NSLog, has its memory alloc released already or did removeObjectAtIndex release only maAllTxt object at index 0? Is it the same with replaceObjectAtIndex- method?


Second question is, what is the difference with "self.variable" and "variable" if variable have add to class header file?

[hello24]

strTxt is an autoreleased NSString.

BTW, there is a mistake in your code - make sure you have nil as the final element in initWithObjects.
NSMutableArray *maAllTxt = [NSMutableArray alloc] initWithObjects:strTxt, strTxt2, nil];

Also, there is a memory leak in there as maAllTxt is never released. You seem pretty confused about memory management - maybe you should read a relevant chapter in a good iPhone dev book.

self.variable uses the setter/getter whilst variable accesses your variable directly.
I recommend to always use self.variable as this makes sure that, when the value changes, the old content is released and the new one retained.

[georgeburns]

Originally Posted by hello24

self.variable uses the setter/getter whilst variable accesses your variable directly.

Could you point me to a reference page that talks about that? Thanks

[hello24]

Here is a pretty good explanation:
http://www.iphonedevsdk.com/forum/ip...es-newbie.html

Also, can you please consider changing your signature - I believe you're trying too hard to sell and forgot us, the poor users that are reading this forum.

[georgeburns]

Originally Posted by hello24

Here is a pretty good explanation:
http://www.iphonedevsdk.com/forum/ip...es-newbie.html

Also, can you please consider changing your signature - I believe you're trying too hard to sell and forgot us, the poor users that are reading this forum.

Sorry... quoted the wrong part in my last reply.. I meant to quote this...
"I recommend to always use self.variable as this makes sure that, when the value changes, the old content is released and the new one retained. "

I wasn't aware that one would run the risk of not releasing something using direct access.

[Alec]

Thank you a lot for help and sorry my bad english. Now I understand my examples much better.
I found pretty good document from the websites of apple:
Mac Dev Center: Memory Management Programming Guide for Cocoa: Introduction