Modifying an input NSString value in a Objective-C method

In terms of memory management, is it correct to modify the input variable content in the fol开发者_如何学JAVAlowing method?

- (NSMutableArray *) extractResults:(NSString *)content {
  ...
  regex = [NSRegularExpression ...];
  content = [regex stringByReplacingMatchesInString:content
                                            options:0
                                              range:NSMakeRange(0, [content length])
                                       withTemplate:@""];
  ...
}

In this particular case I do not care if the value remains modified outside the method scope. Just wondering if that assignment produces a memory leak.

Thanks!

No, it doesn't produce a leak because the return value of stringByReplacing... is autoreleased. However, you should be aware that you are not modifying the content object at all. NSString is immutable, so you can't do that, you're creating a new instance and assigning it to the variable.

As content variable is your local variable, so it is correct. You only change memory address that is stored in variable content. Don't forget to release memory, that you pass in variable content.