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!
Look into NSCondition and the Conditions section in the Threading guide. The code will look something like:
NSCondition* condition; // initialize and release this is 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];