How can I view an NSError?

Question

What's the best way to log an NSError ?

- (void)checkThing:(Thing *)thing withError:(NSError *)error {
    NSLog(@"Error: %@", error);
}

Gives me a null message

Answer 1

Looking at the NSError documentation tells me that you'll need to do something like:

NSLog(@"%@",[error localizedDescription]);

This should then give you human readable output

Answer 2

 NSLog(@"Error: %@", error); 

Gives me a null message

Then error is nil , not an NSError instance.

Answer 3

Here's a rough method I use to log errors while developing; (Not for Cocoa-touch)

// Execute the fetch request put the results into array
NSError *error = nil;
NSArray *resultArray = [moc executeFetchRequest:request error:&error];
if (resultArray == nil)
{
    // Diagnostic error handling
    NSAlert *anAlert = [NSAlert alertWithError:error];
    [anAlert runModal];
}

NSAlert takes care of displaying the error.