blob: dfdcf40617391fefbb9f9449f84da648228c796d [file] [log] [blame]
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package signal implements access to incoming signals.
package signal
// BUG(rsc): This package is not yet implemented on Plan 9 and Windows.
import (
var handlers struct {
list []handler
type handler struct {
c chan<- os.Signal
sig os.Signal
all bool
// Notify causes package signal to relay incoming signals to c.
// If no signals are listed, all incoming signals will be relayed to c.
// Otherwise, just the listed signals will.
// Package signal will not block sending to c: the caller must ensure
// that c has sufficient buffer space to keep up with the expected
// signal rate. For a channel used for notification of just one signal value,
// a buffer of size 1 is sufficient.
func Notify(c chan<- os.Signal, sig ...os.Signal) {
if c == nil {
panic("os/signal: Notify using nil channel")
defer handlers.Unlock()
if len(sig) == 0 {
handlers.list = append(handlers.list, handler{c: c, all: true})
} else {
for _, s := range sig {
// We use nil as a special wildcard value for enableSignal,
// so filter it out of the list of arguments. This is safe because
// we will never get an incoming nil signal, so discarding the
// registration cannot affect the observed behavior.
if s != nil {
handlers.list = append(handlers.list, handler{c: c, sig: s})
func process(sig os.Signal) {
defer handlers.Unlock()
for _, h := range handlers.list {
if h.all || h.sig == sig {
// send but do not block for it
select {
case h.c <- sig: