Catching and handle exceptions in Objective-c/Cocoa:

 
    @try {
        if (argc > 1)  {
            @throw [NSException exceptionWithName:@"Throwing a test exception" 
                                           reason:@"Testing the @throw directive." 
                                         userInfo:nil];
        }
    } 
    @catch (id theException) {
        NSLog(@"%@", theException);
    } 
    @finally {
        NSLog(@"This always happens.");
    }
 

Many Cocoa methods use the NSError class in order to provide error feedback about their executions. In order to show the error, just use the code bellow:

 
- (void)logError:(NSError *)error {
    NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey];
    if(detailedErrors != nil && [detailedErrors count] > 0) {
        for(NSError* detailedError in detailedErrors) {
            NSLog(@"  DetailedError: %@", [detailedError userInfo]);
        }
    } else {
        NSLog(@"  %@", [error userInfo]);
    }
}