CODEWITHSUNDEEP
objective-cmemory-managementnsthread
GTAE86
GTAE86

Reputation: 1846

Does the system do a retain on object in performSelector:onThread:withObject:waitUntilDone: when no wait?

Consider the following code - obviously non-ARC:

.  
.  
.  
NSString* someValueToSend= [NSString alloc] initWithString@"Send me! Will I survive?"];  

if([delegate respondsToSelector:@selector(giveMeYourString:)])  
{  
  [delegate performSelector:@selector(giveMeYourString:) onThread:someOtherThread withObject:someValueToSend waitUntilDone:NO];  
}  
[someValueToSend release];  
.  
.  
.

Depending on what else is going on in the application, the delegate may or may not get around to running that selector before someValueToSend is released. Does the "system" do a "courtesy" retain on the object?

If not, and I am in a situation where I cannot block, what is a good strategy for sending a value across the boundary without a leak? Autorelease?

I did find a reference elsewhere that said the object is retained, but I have not seen that in the documentation....

Any input appreciated.

Upvotes: 1

Views: 187

Answers (1)

bbum
bbum

Reputation: 162722

Yes, the system will retain the object.

And, no, autorelease can never be used to protect an object from being released across a thread boundary. Technically, it can in the synchronous case, but don't do that.

Upvotes: 3

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