Error while posting duplicate message in Twitter(MGTwitterEngine)

I am using MGTwitterEngine for iPhone to supp开发者_JS百科ort twitter, I am getting error(403) while posting a message second time how to handle this issue.

That is.. Let the message is "what are you doing" I am posting using [mTwitterEngine sendUpdate:"what are you doing"] for first time it is posted successfully, if i want to post the same message again it is throwing 403 error.

How to handle this? Can i put the alert "Duplicate message" if error no 403? Is 403 error for duplicate messages only?

Added : Is it possible to check if an message is already posted in MGTwitterEngine?

The 403 error is not only for duplicate message so that you cannot throw the error message to user.

http://developer.twitter.com/pages/responses_errors

You have to find the duplicate message in your application code by keeping the last updated message.