Re: Declaring Variables - Setting to nil VS Not Setting?
Re: Declaring Variables - Setting to nil VS Not Setting?
- Subject: Re: Declaring Variables - Setting to nil VS Not Setting?
- From: Nick Zitzmann <email@hidden>
- Date: Thu, 26 Apr 2012 14:33:09 -0600
On Apr 26, 2012, at 2:00 PM, Chris Tracewell wrote:
> I usually use the sample in line 1 when declaring vars inside my methods.
>
> NSString *theString = [NSString string];
Here you are creating a pointer to an empty string. This consumes memory.
> NSString *theString = nil;
Here you are creating a null pointer. This does not consume memory. If the program sends a message to a null pointer, then the runtime will catch it and not send the message.
> NSString *theString;
Here you are declaring an uninitialized pointer. This does not consume memory, but attempting to message it prior to initialization will either cause a crash if it points to an unallocated memory address, or cause bizarre behavior if it points to an allocated memory address.
> when do you use the style shown in line 3?
Only when you will store something in that pointer at a later time in the function/method. Never read from uninitialized memory unless you **really** know what you're doing.
> Thanks and pointers to docs are welcome.
This is C programming language 101, so I'd recommend you read a good book on C programming, particularly one that deals with pointers.
Nick Zitzmann
<http://www.chronosnet.com/>
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