Re: Seeking advice on NSLock usage

FROM : Guy English
DATE : Mon Dec 13 20:48:42 2004

On Mon, 13 Dec 2004 11:54:51 +0000, Jeremy Dronfield
<jeremy.<email_removed>> wrote:
> On further reflection, I may offer both approaches as a user option. If
> my search thread uses the original model instance, the practical side
> effect is that the user can "tune" their search criteria on the fly,
> while a search is in progress. In some situations I  could see this
> being a useful option.

Uh ... wait a second. If your search is going to be running in another
thread and you want to alter the parameters while it's running then
you'll definately need a lock. Changing objects that a thread may be
reading from is bad mojo. Consider:
main thread:
[newCriteria retain];
[criteria release];
search thread then decides to run:
if ( [criteria isEqualTo: @"blah"] ) // app explodes here 'cause
criteria has been released.
main thread:
criteria = newCriteria; // too little to late.

Make sure you put locks around stuff that's going to be accessed by
both threads.

Guy