Add events to those caught for the lifetime of this process.
Interrupt catches Ctrl-C. Terminate(unix) catches Unix SIGTERM,
including systemd's default stop request. User1(unix) and User2(unix)
catch SIGUSR1 and SIGUSR2. WindowResize(unix) catches SIGWINCH.
Duplicate registrations and an empty list do nothing. Repeated events
coalesce and never force exit.
Signal
Signal :: # (opaque)Cooperatively handle signals delivered to the process.
Register before acquiring resources that need application cleanup. A caught
event makes blocking effects return Interrupted; acknowledge it with
[poll!] before retrying an effect or running application cleanup. Catching
does not clean up remote resources automatically.
If Interrupted reaches main!, the platform restores terminal raw mode
and exits with 128 plus the native signal number on Unix, or 130 on Windows.
When several events are pending, Terminate takes precedence, followed by
Interrupt, User1, User2, WindowResize.
Acknowledge pending events, returning each kind at most once, in the order Interrupt, Terminate, User1, User2, WindowResize. An interrupted effect does not acknowledge events itself. Native forced termination cannot be caught.
Kind : [Interrupt, Terminate, User1, User2, WindowResize]Request : [Interrupt, Terminate(Unix), User1(Unix), User2(Unix), WindowResize(Unix)]