PHP GUID...possibility of duplication?

[louis_coetzee]

If I am using a php guid, is it necessary for me to worry about it being duplicated? Is there a way that I can insure that this never happens, because I want to use a guid as an unique id for each of the users in my db, never mind the size, it must be impossible even if I have millions of members.

 

This is how I do it:

$actlink = md5(uniqid(rand(), true));