Passing references as function parameters in Objective-C

Question

I dont undesratand in which situations is more convenient to pass references as functions parameters:

- (void)exportXMLToString:(NSMutableString **)aString

Can I just pass the string by value and have it back when the method finishes to execute ?

Thanks

score 1 · Answer 1 · edited May 23 '17 at 11:55

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You may find the following thread useful. I think your issue is vastly discussed here: Use of pass by reference in Objective-C

edited May 23 '17 at 11:55

Community

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answered Jun 18 '12 at 07:16

rshahriar

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score 0 · Accepted Answer · answered Jun 18 '12 at 07:11

It more convenient to pass references when you do not want an extra copy of String, Extra copy means more space, If you want to read/append the String< It is better if you do not create a new new one. You easily do this by passing String value (create a new one) but that's not very efficient. (you want two glasses space to store 1/2 glass of water :) )

score 0 · Answer 3 · answered Jun 18 '12 at 07:35

As I understand what you are trying to achieve, you could just name your method - (NSString *)xmlStringValue.

It is a matter of style, I personally only use references in ObjC when I have to (it is not really in the spirit of the language imho), and almost exclusively for (NSError **).

Passing references as function parameters in Objective-C

3 Answers3