temporary table shared between multiple users

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Is temporary table or Heap/Memory tables shared between all user?
For e.g
if i have a temporary table named table1 and two users, lets say user1 and user2 dump data to that table, what will user1 and user2 see.
Will both the users see all data or only the data that has been dumped by that particular user.

I have gone through mysql docs but still can't get the idea right.

Need help desparately.