⍝ The send primitive is a dyadic function
⍝ message ⍈ to

message←'Hello there'

⍝ We can send it to ourselves
us←⎕self
us
message ⍈ us

⍝ Let's examine the state of the system
us ⎕threads 0 ⍝ Thread ID
us ⎕threads 1 ⍝ Thread name
us ⎕threads 2 ⍝ Number of messages in mailbox
us ⎕threads 3 ⍝ Approximate C stack usage (in bytes)

⍝ All at once, for all currently running threads
⎕threads 0 1 2 3

⍝ We have one message in our mailbox, let's receive it
⍝ The recieve primitive is a monadic operator
⍝ filter ⍇ timeout
{1 ⍵} ⍇ 0

⍝ Again?
{1 ⍵} ⍇ 0
⍝ The time we asked it to wait was 0, so it failed immediately.
{1 ⍵} ⍇ 5

⍝ What if we don't want it to timeout?
{1 ⍵} ⍇ ⍬  ⍝ No one will send it anything, so it hangs