os/signal: selective signal handling

[gjemiller]

Current signal handling functionality in the runtime handles all signals, preventing
default behavior for SIGTSTP, SIGTTIN, and SIGTTOU.  One proximate effect of this is
that Ctrl-Z from a unix shell does not suspend any Go process that handles signals.
 
It might be generally convenient to have a way to catch only a specific 
subset of all signals, and to have some set of signals have their 
default behaviour. 

It might also occasionally be convenient to have a way to catch a 
signal and then to invoke the signal's default behaviour, or to deliver another signal
to itself or another process.

[adg]

Comment 1:

Labels changed: added packagechange.

Status changed to HelpWanted.

[gopherbot]

Comment 2 by m@capitanio.org:

Currently are also all the signals SIGRTMIN - SIGRTMAX ignored, so it
is in go not possible to use them.

[alberts]

Comment 3:

http://groups.google.com/group/golang-dev/browse_thread/thread/a24470107bc3cac8

[rsc]

Comment 4:

Issue #2161 has been merged into this issue.

[rsc]

Comment 5:

Labels changed: added priority-low, removed priority-medium.

[rsc]

Comment 7:

Labels changed: added priority-someday, removed priority-low.

[rsc]

Comment 8:

Labels changed: added priority-go1.

[robpike]

Comment 9:

Owner changed to builder@golang.org.

[rsc]

Comment 11:

Labels changed: added go1-must.

[dsymonds]

Comment 12:

os/signal has been moved to exp/signal, and so won't be in Go 1. I'm demoting this bug's
priority.

Labels changed: added priority-later, removed priority-go1, go1-must.

Status changed to Thinking.

[rsc]

Comment 13:

Owner changed to @rsc.

Status changed to Started.

[rsc]

Comment 14:

This issue was closed by revision 35586f7.

Status changed to Fixed.