Re: Sending object between threads.
Re: Sending object between threads.
- Subject: Re: Sending object between threads.
- From: Jorge Monteiro <email@hidden>
- Date: Mon, 12 May 2003 21:46:50 -0400
Terry,
You need to implement the NSCopying and NSCoding protocols on all the
objects you want to pass. This will work within the same app or across
apps - using real DO.
Also remember if you pass the object pointer, like suggested before,
you should use an NSLock to lock access to the object so that the 2
threads do not access the object at the same time - if that happens the
app will crash and this problem will be very hard to track later on.
Regards,
Jorge Monteiro
http://www.jomosoft.com
On Thursday, January 23, 2003, at 05:23 AM, Terry Smyth wrote:
Thanks Nico & Jake,
That did the trick. By casting to a uintptr_t I can now see my object
at the other end of the connection. Though I still don't understand
why my objects are not getting encoded and transferred as I had
expected (it seems at present just a pointer to the object is sent).
This is fine for now while I am communicating between threads in the
same app. Later, my worker thread will need to run on a separate
machine, and I will need a full DO implementation - hopefully once
I've done that, I will see my objects encoded and transferred across
the connection.
Thanks for your help,
Terry
On Tuesday, January 21, 2003, at 08:12 pm, Nico wrote:
Hi Terry!
I also ran into this problem.
The simplest way to solve that problem is to pass your
object pointer castet to a uintptr_t.
After received by the worker thread simply cast the
pointer back.
Make sure the object is still valid for the worker.
Maybe you retain the object for the worker and the
worker releases it.
Hope that helps...
Nico
On Montag, Januar 20, 2003, at 07:05 Uhr, cocoa-dev-
email@hidden wrote:
Date: Mon, 20 Jan 2003 17:50:39 +0000
Subject: Sending object between threads.
From: Terry Smyth <email@hidden>
To: email@hidden
Hi,
Following the example given in the Cocoa documentation "Forming
Connections Between Threads", I have implemented a separate thread in
my app to do some stuff, using NSConnection/NSPort to communicate
between the main thread and the worker thread. It all works, except
that I'm having trouble passing my own custom objects to and from the
worker thread (so I can't actually get my worker to do any useful
work!!). I can pass other cocoa objects (eg NSString) just fine, and
they appear intact at the other side of the connection. If I pass my
own object, I just get junk at the other end.
Objects of my custom class conform to NSCoding, but my
encodeWithCoder:
and initWithCoder: methods never get called. Have I missed something
obvious here, or is it more likely a dumb coding bug? I'm going round
in circles reading the documentation, but can't see what I'm doing
wrong. Can anyone suggest what I might have missed, or where I can go
for further reading (better still, is there any sample code which
does
this - I couldn't find any?)
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