This is how to check if an `NSError**` or the data it points to is empty. Very straight forward, we check if pointer is nil before checking if the data it points to is nil.Doing `*error` on a nil pointer will raise an exception.

iOS - Checking empty NSError** param.m

+ (void)errTest2:(NSError**)error {
    // Use error object ONLY IF it is provided, otherwise it will CRASH!!!
    if (error != NULL) {
        NSLog(@"Creating error object...");
        *error = [NSError errorWithDomain:...];
    }
    else { 
        NSLog(@"No error object provided, skip error object creation.");
    }
}

*error will initially point to a nil pointer so the if block will always fail & move to else.

Sorry, fixed. Now checking against NULL instead :)