erlang - How does receive block work? -

i had simple question , can't seem find answer it. question if have function recording state (recursive) , send multiple messages it, keep going through receive block until no longer has messages in "mailbox"?

state(fridge) ->     receive         pat1 ->             io:format("ok"),             state(s);         pat2 ->             io:format("not ok"),             state(s)     end. 

so if i'd send process 3 messages (pat1, pat2, pat1) using "!" , not able go loop before receiving messages still print out following?

1> "ok" 2> "not ok" 3> "ok" 

sorry if isn't put, simplifying question might make hard picture asking.

your question isn't clear seem asking whether process receive 3 messages if they're sent before target process has called receive — if that's question, answer yes. when send message process, goes process's message queue until process calls receive remove message queue , deal it.

if call erlang:process_info(pid, messages) pid receiver's process id, can see messages in queue. might try erlang shell.

as extreme example of message queueing, under heavy load conditions can source of out-of-memory problems if receiver can't keep fast sender. under these conditions, receiver's message queue might grow without bound until system runs out of memory.