Today I Learned

A Hashrocket project

Creating A PID

Often times, when invoking a function that spawns a process, the PID of the spawned process is returned and we bind to it. That PID is a reference to some BEAM process in our system.

We can create our own references using the pid/3 function.

Let’s assume we have the following processes, among others, in our system at the moment.

> Process.list |> Enum.reverse |> Enum.take(3)
[#PID<0.284.0>, #PID<0.283.0>, #PID<0.282.0>]

We can create a reference to any of them using the three number parts that they are made up of.

> pid(0, 284, 0)
#PID<0.284.0>

See, it’s alive.

> pid(0, 284, 0) |> Process.alive?
true

What if we make up a PID that doesn’t actually reference any process?

> pid(0, 333, 0) |> Process.alive?
false

Note: there is also a pid/1 version of the function. See h pid for more details.

Looking for help? Elixir is quickly gaining momentum for web applications that need concurrency, performance, and the ability to connect to many different clients. The developers at Hashrocket are learning along with the rest of the development community that Elixir and Phoenix are viable Rails alternatives for the right application. Contact us if you need help with your Elixir project.