How to check if your promotional code valid?

Apple provides developers with the ability to distribute free promotional codes to their applications. The authors use their programs for the promotion of products - give the codes to journalists, bloggers, podcasters and other observers.

Promotional codes have limited validity, and yet they are burned, when a new version of the application. How to check whether the code is valid?

Apple is not such a possibility explicitly. But there is a workaround, the developer of the proposed Cam (author Walkabout).

Their advice is simple: razlogintes from the iTunes Store, then sign in again, but do not save the password; restart iTunes. Now that iTunes is working, enter the promotional code. If it is invalid, Apple will report about it (for example: This code has been used - codes may be used only once - This code has already been used, the codes only be used once). If the working code, iTunes will prompt you for your password. Do not do this. Refused to continue the redemption procedure code, you keep it.

If this procedure is carried out with a saved password, iTunes simply redeem your code. If you log out and then do not save your password, iTunes will let you know that the promotional code is valid and will not repay it prematurely.

UPDATE. You can do even easier: simply razloginittes and enter the code. iTunes even nezaloginennomu user reports on the status of this code: