Underscore before property name, in setter

Question

I wrote a setter method -

- (void)setMyProp:(MyProp *)myProp{
    _myProp = myProp;
}

How is underscore put before property name is working? I know this question has been asked, but they are about user setting property name to _myProp, some convention. I am not synthesizing or changing the property name. How this underscore is working?

And here's another 16: http://stackoverflow.com/q/5582448/ http://stackoverflow.com/q/6049269/ http://stackoverflow.com/q/2371489/ http://stackoverflow.com/q/7174277/ http://stackoverflow.com/q/5659156 http://stackoverflow.com/q/837559/ http://stackoverflow.com/q/6146244/ http://stackoverflow.com/q/10651535/ http://stackoverflow.com/q/6124109/ http://stackoverflow.com/q/8145373/ http://stackoverflow.com/q/3521254/ http://stackoverflow.com/q/6064283/ http://stackoverflow.com/q/9696359/ http://stackoverflow.com/q/5521499/ http://stackoverflow.com/q/5466496/ http://stackoverflow.com/q/2114587/ — jscs, Mar 06 '13 at 18:56

Anoop Vaidya · Answer 1 · 2013-03-07T03:22:12.503

1

If you are using latest version of LLVM, then the compiler creates @synthesize for you with the syntax:

@synthesize myProp=_myProp;

Therefore you are able to use _myprop even though you have not synthesized explicitly.

~~*SideNote: _myProp makes you access the property directly, while self.myProp will call accessor. Always use self.myProp~~

edited Mar 07 '13 at 03:22

answered Mar 06 '13 at 18:34

Anoop Vaidya

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3

Your side note is incorrect. Using `_myProp` accesses the ivar directly. The property is not used at all this way. – rmaddy Mar 06 '13 at 19:10
2

"Always" is also wrong... You would never use it in the setter itself and should not use it in your init methods referring to the docs ;) – HAS Mar 06 '13 at 19:24
@rmaddy: I cut my sidenote. – Anoop Vaidya Mar 07 '13 at 03:22
@HAS: I cut my sidenote. – Anoop Vaidya Mar 07 '13 at 03:23

Underscore before property name, in setter

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