Crash log without crash?

Question

Hey this may be a stupid question but I couldn't find the answer anywhere, apologies if the answer is easily found and if my research skills are pants.

anyway is it possible to generate a crash report when an app doesn't crash? so say if a user encounters a bug could there be an option to allow them to generate a crash report which can then be sent to me? also how would I go about doing this?

Thanks for any help :)

Answer 1

I have used it couple of times when I had to print stack trace:

+ (NSArray *)backtrace
{
    void* callstack[128];
    int frames = backtrace(callstack, 128);
    char **strs = backtrace_symbols(callstack, frames);

    int i;
    NSMutableArray *backtrace = [NSMutableArray arrayWithCapacity:frames];
    for (
        i = UncaughtExceptionHandlerSkipAddressCount;
        i < UncaughtExceptionHandlerSkipAddressCount +
            UncaughtExceptionHandlerReportAddressCount;
        i++)
    {
        [backtrace addObject:[NSString stringWithUTF8String:strs[i]]];
    }
    free(strs);

    return backtrace;
} 

"When an application crashes on the iPhone, it disappears without telling the user what happened. However, it is possible to add exception and signal handling to your applications so that an error message can be displayed to the user or you can save changes. It is even possible to try to recover from this situation without crashing at all." Look at http://cocoawithlove.com/2010/05/handling-unhandled-exceptions-and.html

Answer 2

Here's what I use for my stacktraces:

        NSArray *callStackArray = [exception callStackReturnAddresses];
        int frameCount = [callStackArray count];
        void *backtraceFrames[frameCount];

        for (int i=0; i < frameCount; i++) {
            backtraceFrames[i] = (void *)[[callStackArray objectAtIndex:i] unsignedIntegerValue];
        }

        char **strs = backtrace_symbols(backtraceFrames, frameCount);

        NSMutableArray *backtraceArray = [NSMutableArray arrayWithCapacity:frameCount];
        for (int i = 0; i < frameCount; i++) {
            NSString *entry = [NSString stringWithUTF8String:strs[i]];
            [backtraceArray addObject:entry];
        }
        free(strs);

You just have to make sure you don't do any harm to your app: http://landonf.bikemonkey.org/2011/09/14. You could also use PLCrashReporter to handle all your crashes or if you're lazy like me, use a service like Crittercism

Answer 3

I used to use backtrace_symbols for handling my crashes too, but then I found out that it could be dangerous since the method is not async-safe. I've since looked at a bunch of crash reporting solutions and went with Crittercism for my apps and it's been pretty sweet!

Answer 4

I suggest you check out TestFlight SDK released a few days ago. It has some awesome features like remote logging and even live crash reports.

Answer 5

For an ad hoc version, you could just call the function abort(), or throw and exception of some kind.

An App Store version will not be allowed to ship if it crashes at all during testing.