imap_search question

hi. in the php manual the entry for imap_search states it has 3 arguments "imap_search ( resource imap_stream, string criteria, int options)" i get the first 2, but whats the third. at the end of the page it says "Valid values for flags are SE_UID, which causes the returned array to contain UIDs instead of messages sequence numbers. " so should imap_search ( $myStream, "ALL", SE_UID); return an array of the UIDs of the emails? because this is what i want. i need to work with the UIDs not the mesage numbers cheers folks Greg Brant