[swift-dev] Glibc struct sigaction and sigaction

[Joseph Bell]

Using signal rather than sigaction does work:

typealias SignalHandler = __sighandler_t

func trap(signum:Signal, action:SignalHandler) {
  signal(signum.rawValue, action)
}

Not ideal but serviceable.  I'd still be curious to understand whether
sigaction can be used.
Joe


On Sun, Jan 10, 2016 at 11:01 PM, Joseph Bell <joe at iachieved.it> wrote:

> Not sure if anyone has ran into this use case before; thought I'd ask.
>
> On many Unices the sigaction function is used to trap receipt of a signal
> and run a signal handler action.  I want to use this to trap SIGINT and I
> think Swift's presentation of Glibc is leaving the struct sigaction
> definition masked by the function definition (see man 2 sigaction).
>
> Example:
>
> import Glibc
>
> enum Signal: Int32 {
>   case HUP    = 1
>   case INT    = 2
>   case QUIT   = 3
>   case ABRT   = 6
>   case KILL   = 9
>   case ALRM   = 14
>   case TERM   = 15
> }
>
> typealias SignalHandler = (Int) -> Void
>
> func trap(signal:Signal, action:SignalHandler) {
>   var act:sigaction = sigaction() // would expect this to be struct
>   act.sa_handler = &action        // but woe, it is not
>   sigaction(signal.rawValue, &act, nil)
> }
>
> trap(.INT) { signal in
>   print("Intercepted signal \(signal)")
> }
>
> print("going to sleep...")
> sigsuspend(nil)
>
> This code gives:
>
> sighandle.swift:17:3: error: value of type 'sigaction' has no member
> 'sa_handler'
>   act.sa_handler = &action        // but woe, it is not
>
> Any ideas of working around this or alternative approach to trapping
> signals on Linux with Swift?
>
> Joe
>
> Credit for original to Adam Sharp's gist at
> https://gist.github.com/sharplet/d640eea5b6c99605ac79
>
> --
> ---
> http://dev.iachieved.it/iachievedit/
> @iachievedit
>



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