I'm facing a problem while i want to post just text-msg to FB friend wall. I know that i can share link and than additionally write the msg of the post. But i am wondering if there is any way automatically to pass the msg field as a param to the dialog. I want my text to be shown on the place of the hint "Write something..."
It is not possible and not allowed. Check out the platform policy:
2.3: Don't prefill captions, comments, messages, or the user message parameter of posts with content a person didn’t create, even if the person can edit or remove the content before sharing.