Its always been a little painful when you get an exception and the debugger decides not to cooperate, leaving you with something like:
Thanks!
As far as I could work out, traditional methods of grabbing a symbolic stack trace don’t work on the iPhone. (If I am remembering right, I don’t think NSStackTraceKey exists in UIKit.)
A little while ago I hacked the GTMStackTrace from google-toolbox-for-mac, to lookup the symbolic stack trace from the call stack return addresses (NSException#callStackReturnAddresses introduced in 10.5) and print it out using NSSetUncaughtExceptionHandler. Life has been a little bit easier ever since. Thankfully, the awesome people who work on GTM added it in themselves (see GTMStackTrace.h#61). Here is how you might set it up, in main.m:
#ifdef DEBUG
#import
#import "GTMStackTrace.h"
void exceptionHandler(NSException *exception) {
NSLog(@"%@", GTMStackTraceFromException(exception));
}
#endif
int main(int argc, char *argv[]) {
#ifdef DEBUG
NSLog(@"Debug enabled");
NSDebugEnabled = YES;
NSZombieEnabled = YES;
NSDeallocateZombies = NO;
NSHangOnUncaughtException = YES;
[NSAutoreleasePool enableFreedObjectCheck:YES];
NSSetUncaughtExceptionHandler(&exceptionHandler);
#endif
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, nil);
[pool release];
return retVal;
}
For me, DEBUG is set in GCC_PREPROCESSOR_DEFINITIONS via the awesome GTM xcconfg files, which you should also be using. Hopefully, you should get a trace that looks like:
[Session started at 2008-12-30 00:10:13 -0800.] 2008-12-30 00:10:15.772 TestExceptionIPhone[8493:20b] Debug enabled 2008-12-30 00:10:15.830 TestExceptionIPhone[8493:20b] #0 0x92c5614b _NSExceptionSetRubyToken() (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation) #1 0x9657ce3b objc_exception_throw() (/usr/lib/libobjc.A.dylib) #2 0x92c55f2b +[NSException raise:format:arguments:] (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation) #3 0x92c55f6a +[NSException raise:format:] (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation) #4 0x002350 +[TestExceptionIPhoneAppDelegate applicationDidFinishLaunching:] (/Users/gabe/Library/Application Support/iPhone Simulator/User/Applications/586E48B6-B758-4DBD-A534-D6927DA74583/TestExceptionIPhone.app/TestExceptionIPhone) #5 0x30a4e01a +[UIApplication performInitializationWithURL:asPanel:] (/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator2.2.sdk/System/Library/Frameworks/UIKit.framework/UIKit) #6 0x30a57363 +[UIApplication _runWithURL:] (/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator2.2.sdk/System/Library/Frameworks/UIKit.framework/UIKit) #7 0x900425ee +[NSRunLoop runMode:beforeDate:] (/System/Library/Frameworks/Foundation.framework/Versions/C/Foundation) #8 0x92bdcb45 CFRunLoopRunSpecific() (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation) #9 0x92bdccf8 CFRunLoopRunInMode() (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation) #10 0x31564600 GSEventRunModal() (/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator2.2.sdk/System/Library/PrivateFrameworks/GraphicsServices.framework/GraphicsServices) #11 0x315646c5 GSEventRun() (/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator2.2.sdk/System/Library/PrivateFrameworks/GraphicsServices.framework/GraphicsServices) #12 0x30a4ec98 +[UIApplication _run] (/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator2.2.sdk/System/Library/Frameworks/UIKit.framework/UIKit) #13 0x30a5a094 UIApplicationMain() (/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator2.2.sdk/System/Library/Frameworks/UIKit.framework/UIKit) 2008-12-30 00:10:15.834 TestExceptionIPhone[8493:20b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Give me a good stack trace'
And the source of the exception usually starts around the 5th line.
