How can I use NSError in my iPhone App?

Question

I am working on catching errors in my app, and I am looking into using NSError. I am slightly confused about how to use it, and how to populate it.

Answer 1

Great answer Alex. One potential issue is the NULL dereference. Apple's reference on Creating and Returning NSError objects

...
[details setValue:@"ran out of money" forKey:NSLocalizedDescriptionKey];

if (error != NULL) {
    // populate the error object with the details
    *error = [NSError errorWithDomain:@"world" code:200 userInfo:details];
}
// we couldn't feed the world's children...return nil..sniffle...sniffle
return nil;
...