os/signal: selective signal handling
Restore package os/signal, with new API:
Notify replaces Incoming, allowing clients
to ask for certain signals only. Also, signals
go to everyone who asks, not just one client.
This could plausibly move into package os now
that there are no magic side effects as a result
of the import.
Update runtime for new API: move common Unix
signal handling code into signal_unix.c.
(It's so easy to do this now that we don't have
to edit Makefiles!)
Tested on darwin,linux 386,amd64.
Fixes #1266.
R=r, dsymonds, bradfitz, iant, borman
CC=golang-dev
https://golang.org/cl/3749041
diff --git a/doc/go1.html b/doc/go1.html
index 8d01d96..0cf0c0a 100644
--- a/doc/go1.html
+++ b/doc/go1.html
@@ -1363,6 +1363,39 @@
The compiler will catch code using the old interface.
</p>
+<h3 id="os/signal">The os/signal package</h3>
+
+<p>
+The <code>os/signal</code> package in Go 1 replaces the
+<code>Incoming</code> function, which returned a channel
+that received all incoming signals,
+with the selective <code>Notify</code> function, which asks
+for delivery of specific signals on an existing channel.
+</p>
+
+<p>
+<em>Updating</em>:
+Code must be updated by hand.
+A literal translation of
+</p>
+<pre>
+c := signal.Incoming()
+</pre>
+<p>
+is
+</p>
+<pre>
+c := make(chan os.Signal)
+signal.Notify(c) // ask for all signals
+</pre>
+<p>
+but most code should list the specific signals it wants to handle instead:
+</p>
+<pre>
+c := make(chan os.Signal)
+signal.Notify(c, syscall.SIGHUP, syscall.SIGQUIT)
+</pre>
+
<h3 id="runtime">The runtime package</h3>
<p>
