How to track a user's action for posting on facebook (actually posted VS canceled)?

Question

To be specific, I'm using Unity3d (targetting iOS 8) and a plugin to post on facebook. actually two plugins that unfortunatelly behaved similarely; they both failed at doing what I expected, meanning that the problem doesn't come from them (prime31 & u3dxt). The answer I'm looking for doesn't have to be specific to my setup.

What I want to do, is to let the user post a message on his facebook timeline, and reward him upon doing so. The problem is that I can't properly track whether the post did complete or not, due to the follwing situations:

• If the facebook app is not installed on the iOS device, cancelling or failling on posting due to whathever reason returns "false", while successfully posting returns "true".
• If the facebook app is installed on the iOS device, cancelling or actually completing the post, all return "true".

Any idea why having the fb app installed make things work differently? is rewarding people by posting something that is supposed to work fine? or am I trying to do something not intended to be?

Thanks

Answer 1

Only incentivize a person to log into your app, enter a promotion on your app’s Page, or check-in at a place. Don’t incentivize other actions.

Source: https://developers.facebook.com/policy/

Meaning, you are not allowed to reward users in any way for sharing something on their wall. That´s why Facebook made it hard to check if something got shared.