How to pause an NSThread until notified?

cocoa, nsthread

Solution

Look into NSCondition and the Conditions section in the Threading guide. The code will look something like:

NSCondition* condition; // initialize and release this as your app requires.

//Worker thread:
while([NSThread currentThread] isCancelled] == NO)
{
    [condition lock];
    while(partySuppliesAvailable == NO)
    {
        [condition wait];
    }

    // party!

    partySuppliesAvailable = NO;
    [condition unlock];
}

//Main thread:
[condition lock];
// Get party supplies
partySuppliesAvailable = YES;
[condition signal];
[condition unlock];

Problem

I have a worker thread that I want to do one bit of its task, then pause & wait for the "ok, continue" command from another thread, then pause & wait, etc. The use case is: the controlling object is a view that I want to display information about what's going on inside the worker-thread, and allow me to "single-step" through the worker as it does it's thing. The rather ugly and heavy-handed thing that I have in my worker is this: ``` NSLog(@"paused"); paused = YES; while (paused) { [NSThread sleepForTimeInterval:0.25]; } NSLog(@".. continuing"); ``` ...But I can't help but think that there must be a nicer way, perhaps involving NSLocks, or some such. Comments, hints suggestions? Thanks!

Original source