Question

I writing my first OS X command line program which is a server style program. It’s job is to process various information and respond to other events.

I have the following code in my main.m

int main(int argc, const char * argv[]) {
    @autoreleasepool {

        PIPieman *pieman = [[[PIPieman alloc] init] autorelease];
        [pieman start];

        NSRunLoop *loop = [NSRunLoop currentRunLoop];
        while (!pieman.finished && [loop runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]);

    }
    return 0;
}

I got this code from various documents and the basic idea is that once pieman.finished is set to YES, that the program then exits.

The problem I have is that the flag is being set by code inside pieman, but the run loop is not being triggered, so the program does not exit. I’ve been looking for ways to trigger the run loop and there seem to be a variety, but none that feel like a good solution. For example I could reduce the beforeDate: to a few seconds to cause periodic triggering of the run loop.

My preference would be that something triggers the run loop on the change of the finished boolean value.

Any suggestions?

Answer 1

You need to tell the run loop to return from runMode:beforeDate:. The NSRunLoop class doesn’t define a message to do that, but NSRunLoop is built on CFRunLoop, and the CFRunLoopStop function does what you need.

@implementation PIPieman

...

- (void)setFinished:(BOOL)finished {
    _finished = finished;
    CFRunLoopStop(CFRunLoopGetMain());
}