# Processes
**Processes** are the Elixir equivalent of threads. Threads are used in [Concurrent Programming](https://www.educative.io/answers/what-is-concurrent-programming) to simultaneously carry out functions.

# Inter-process messaging
Messages can be transmitted among different processes in Elixir. This operation is done using the `send` function and the `receive do` operator.  

processId = self()

spawn fn -> send(processId, {:hello, "Message sent and received"}) end

receive do
  {:hello, msg} -> IO.puts msg
end


ElixirEnvironment

In this program, a process is started using the `spawn` function. This process sends a message with the key `:hello` to the main thread. The main thread's process ID is obtained using the `self()` function and stored in the `processId` variable.

Processes can also be programmed to wait a certain amount of time for a message, and then do something else if no message that matches the possible keys arrives.

processId = self()

spawn fn -> send(processId, {:nonmatchingkey, "Message"}) end

receive do
  {:hello, msg} -> IO.puts msg
  {:world, _msg} -> IO.puts "Key matches"
after
  1_000 -> IO.puts "No matching key received within 1 second"
end


This example does the same things as the previous example, except there is a timer on the receiving operator. When the timer runs out, it outputs the "no" message with any matching key that has been received. The spawned process does send a message; however, this message's key does not match with any of the set keys.

Elixir.tar.gz

How to send and receive messages in Elixir processes

Elixir processes communicate via the send function and the receive do operator, enabling efficient concurrent programming.