Is ghusl obligatory upon a man if he has a wet dream and does not find water in the dream, and what is the prescribed method for the obligatory ghusl?

If a sleeper awakens and sees semen, ghusl (ritual bath) becomes obligatory, whether he had a wet dream or not. However, if he sees nothing, then ghusl is not obligatory, even if he dreamt that he was engaging in sexual intercourse. This is based on the hadith of Umm Sulaym: "Is ghusl obligatory for a woman if she has a wet dream?" He (the Prophet) said: "Yes, if she sees fluid." And based on the hadith of 'Aisha concerning a man who finds wetness but does not recall a wet dream, so he performs ghusl; and concerning a man who sees that he had a wet dream but finds no wetness, then ghusl is not obligatory for him. There is no difference in this ruling between men and women.