How should I deal with resource cleanup on interru...

# kotlin-native

[martmists]

How should I deal with resource cleanup on interrupt signals? I had a look at https://dev.to/mreichelt/handling-sigint-in-kotlin-native-2ac6 but it seems like a staticCFunction can't take local variables to stop the loop or similar.

var loop = true
        // TODO: Make this compatible with windows
        signal(SIGINT, staticCFunction<Int, Unit> {
            loop = false
        })
        while (loop) {
            Pa_Sleep(20)  // Sleep 20ms
        }
        io.cleanup()
        Pa_Terminate()

[ephemient]

POSIX signal API is quite limiting whether you're in C or Kotlin

[ephemient]

as the callback is static, it can only reference globals

[martmists]

Then what should I do to handle ^C? I didn't see any methods for it in stdlib (not that stdlib really adds many platform-independent functions in the first place)

[ephemient]

it can set a global variable which you check in your loop

[ephemient]

in C, your only options are to do that or to use siglongjmp, but the latter isn't an option in K/N, so use the former

[napperley]

Top level functions can be called in the event handlers.

[ephemient]

yes, but the general rule is that only async-signal-safe functions may be called from signal handlers, or else unintended program behavior may rise

[ephemient]

as Kotlin doesn't document anything as being async-signal-safe, do as little as possible from your signal handlers

[napperley]

Just delegate the heavy duty work from the event handler to dedicated functions. The Kotlin Native Runtime does get in the way at times; be aware when the KN Runtime is throwing runtime errors that widespread changes (mainly minor ones) might need to be made to the program.

[ephemient]

if you are call a function from a signal handler, you are still in the signal handler. you need to return or siglongjmp out of it in order to be in a state that is safe to call non-async-signal-safe functions.