Simple signal handling in Swift

trap.swift

import Darwin

enum Signal: Int32 {
  case HUP    = 1
  case INT    = 2
  case QUIT   = 3
  case ABRT   = 6
  case KILL   = 9
  case ALRM   = 14
  case TERM   = 15
}

func trap(signal: Signal, action: @convention(c) Int32 -> ()) {
  // From Swift, sigaction.init() collides with the Darwin.sigaction() function.
  // This local typealias allows us to disambiguate them.
  typealias SignalAction = sigaction

  var signalAction = SignalAction(__sigaction_u: unsafeBitCast(action, __sigaction_u.self), sa_mask: 0, sa_flags: 0)

  withUnsafePointer(&signalAction) { actionPointer in
    sigaction(signal.rawValue, actionPointer, nil)
  }
}

trap(.INT) { signal in
  print("intercepted signal \(signal")
}

print("going to sleep...")

sigsuspend(nil)