CODEWITHSUNDEEP
iosobjective-cobjective-c-blocksgcdasyncsocket
SukyaMaki
SukyaMaki

Reputation: 183

iOS - No stack trace when calling dispatch_async

I've created some example code to demonstrate my problem.

- (void) test {

    void (^handler)(void)  = ^ {

        NSArray *test = [NSArray array];
        [test objectAtIndex: 5];
    };

    handler = [handler copy];

    dispatch_async(dispatch_get_main_queue(), handler);
}

When I call the test method I don't get a stack trace. The debugger just stops at main.m and has this line highlighted

int retVal = UIApplicationMain(argc, argv, nil, NSStringFromClass([FantasyUniversalAppDelegate class]));

If I remove the dispatch_async and just call handler(); then I do get a stack trace. Can some one explain why this is and is there a way to get a more descriptive stack trace?

Right now I am using Flurry to show me crashes but the crashes it is showing me isn't very useful because I get a very non-descriptive stack trace (which is symbolicated). It looks like this:

Thread: Unknown Name
0     libsystem_kernel.dylib                0x3a224eb4 mach_msg_trap + 20
1     CoreFoundation                        0x32067045 __CFRunLoopServiceMachPort + 129
2     CoreFoundation                        0x32065d5f __CFRunLoopRun + 815
3     CoreFoundation                        0x31fd8ebd CFRunLoopRunSpecific + 357
4     CoreFoundation                        0x31fd8d49 CFRunLoopRunInMode + 105
5     GraphicsServices                      0x35b9c2eb GSEventRunModal + 75
6     UIKit                                 0x33eee301 UIApplicationMain + 1121
7     IOSTestApp                        0x00025d7b main (main.m:14)

Upvotes: 3

Views: 645

Answers (1)

George Green
George Green

Reputation: 4915

You could wrap your code in a 

@try {
    NSArray *test = [NSArray array];
    [test objectAtIndex: 5];
}
@catch {
    // Get the stack track for the current thread
    NSArray *stacktrace = [NSThread callStackSymbols];
    // Do something with the symbols
}

all within the block that you are dispatching. Though I'm sure there is a much nicer way!

Upvotes: 0

Related Questions