I would like to know if the function Process.exit(pid, :kill) Is synchronous : once the function has returned, are we sure that no more code from the process pid will be executed ? If not how could we kill a process in a synchronous way ? Best

I am not sure that the function is synchronous, but to be sure, you could first set a monitor on the process with Process.monitor, then kill it, then wait for the :DOWN message from the monitor.

Because the Elixir documentation (as well as the Erlang documentation of :erlang.exit/2 , which this function delegates to) only mention “sends an exit signal”, I am fairly certain that the function is asynchronous. The approach mentioned by @lud works. However, this will not (always) prevent other …

Here is what I try to achieve : I want to run a process and be able to kill it if needed. When the process is either killed or terminates normally, there is a piece of code that I always want to run. The issue I see with @lud’s solution is the following : To monitor a process, you need a pid. So wh…

From the documentation of Process.monitor/1 : If the process is already dead when calling Process.monitor/1 , a :DOWN message is delivered immediately. So you will receive the :DOWN message in that case as well.

Well, then it seems to be a good way to implement what I want :slight_smile:

Also if you call Process.monitor on a pid that is not alive, the down message will contain :noproc as the reason, so you will know your process was not alive.

if you use spawn_monitor/3 you will remove the race condition on starting the process

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Killing a process synchronously

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archimondain August 18, 2019, 12:35pm 6

Well, then it seems to be a good way to implement what I want