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      1 // Copyright 2012 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 package signal
      6 
      7 import (
      8 	"os"
      9 	"syscall"
     10 )
     11 
     12 var sigtab = make(map[os.Signal]int)
     13 
     14 // In sig.s; jumps to runtime.
     15 func signal_disable(uint32)
     16 func signal_enable(uint32)
     17 func signal_ignore(uint32)
     18 func signal_recv() string
     19 
     20 func init() {
     21 	signal_enable(0) // first call - initialize
     22 	go loop()
     23 }
     24 
     25 func loop() {
     26 	for {
     27 		process(syscall.Note(signal_recv()))
     28 	}
     29 }
     30 
     31 const numSig = 256
     32 
     33 func signum(sig os.Signal) int {
     34 	switch sig := sig.(type) {
     35 	case syscall.Note:
     36 		n, ok := sigtab[sig]
     37 		if !ok {
     38 			n = len(sigtab) + 1
     39 			if n > numSig {
     40 				return -1
     41 			}
     42 			sigtab[sig] = n
     43 		}
     44 		return n
     45 	default:
     46 		return -1
     47 	}
     48 }
     49 
     50 func enableSignal(sig int) {
     51 	signal_enable(uint32(sig))
     52 }
     53 
     54 func disableSignal(sig int) {
     55 	signal_disable(uint32(sig))
     56 }
     57 
     58 func ignoreSignal(sig int) {
     59 	signal_ignore(uint32(sig))
     60 }
     61