What does "?" mean in Erlang?

Question

I see alot of code in erlang with a question mark before it, what does it mean? Is it Macros or can it be used in another way? Example:

    {Total, Pids} = run(10, 20),
    ?assertEqual(200, Total),
    ?assert(processes_stopped(Pids)).

    or:

    ?MODULE

Answer 1

When you try call macros, you need add in start of name ‘?’. Notes: the macros can create with or without arguments.