Re: Hang during AESend
Re: Hang during AESend
- Subject: Re: Hang during AESend
- From: Quincey Morris <email@hidden>
- Date: Tue, 13 May 2014 13:46:41 -0700
On May 13, 2014, at 13:03 , Trygve Inda <email@hidden> wrote:
> NSAppleEventDescriptor *appleEvent = [NSAppleEventDescriptor
> appleEventWithEventClass: kMyAEClass
> eventID: kMyAEEventID
> targetDescriptor: targetDescriptor
> returnID: kAutoGenerateReturnID
> transactionID: kAnyTransactionID];
> AESendMessage([appleEvent aeDesc], NULL, kAENoReply | kAENeverInteract,
> kAEDefaultTimeout);
What memory model? ARC?
You’re getting back back a NSAppleEventDescriptor with +0 semantics, which means (if ARC) it’s going to be locally retained, then released when it goes out of scope (possibly a scope optimized optimized to the last reference).
What you’re passing to AESendMessage is an interior pointer (‘aeDesc’ is marked NS_RETURNS_INNER_POINTER in the headers). AFAIK that keeps the underlying object alive *in the calling code* long enough for the interior pointer to be passed safely into the called function, but no longer.
In particular, I don’t know that the interior pointer can be assumed to be valid for the entire length of the called function’s execution. Of course, there’d have to be asynchronous activity (or perhaps a autorelease pool drain inside the called function) for this to matter, but since you’re not asking for a reply, that seems possible.
So, my theory: memory management bug in your code. A simple way to test this would be to put ‘[appleEvent self];’ after the AESendMessage call, and see if the problem goes away.
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