Std.Process

Low-level process control: exiting the VM and catching panics.

Types

SignalKind

type SignalKind =
  | SigHup
  | SigQuit
  | SigAbrt
  | SigAlrm
  | SigTerm
  | SigUsr1
  | SigUsr2
  | SigChld
  | SigTstp

OS signals that can be observed via the Signal effect. Note: SIGINT (Ctrl-C) and SIGKILL are not in this list — SIGINT is claimed by the BEAM break handler and SIGKILL is uncatchable at the OS level. For graceful shutdown, send SIGTERM (e.g. kill -TERM <pid>).

Effects

Signal

effect Signal {
  fun await_signal : (kind: SignalKind) -> Unit
}

Signal effect: blocks the calling process until the given OS signal arrives.

Handlers

beam_signal

handler beam_signal for Signal

Native handler for the Signal effect.

Functions

exit

fun exit : (code: Int) -> a

Immediately terminates the VM with the given exit code. This is equivalent to erlang:halt/1.

shutdown

fun shutdown : (code: Int) -> a

Gracefully shuts down the VM with the given exit code. Flushes IO, runs shutdown procedures, then terminates. This is equivalent to init:stop/1.

catch_panic

fun catch_panic : (f: Unit -> a needs {..e}) -> Result a String needs {..e}

Run a function and recover if it panics. Returns Ok(value) on success, Err(message) if the function panicked. Panics still crash the program by default — this is an opt-in recovery boundary.