Get the current function used to handle control+z

exodist has asked for the wisdom of the Perl Monks concerning the following question:

Hello monks, I am writing a module that gets input in raw mode and interprets the special chartacters such as escape, insert, F1-F12, and control keys such as control+a-z.

Currently I have actions occur when certain keys are pressed. I want these to be overridable. For control+c I bound it like so:
'<CONTROL+C>' => sub { exit(0) };
I need to do something similar for control+z, to make it background the process. At first I tried this:
'<CONTROL+Z>' => $SIG{INT};
But it seems this is empty unless set to something new.

I need to know of a way to do this if it is possible.

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I would rather take 30 minutes to re-invent the wheel then take 30 days to learn how to use someone else's. Before pestering me about my re-invention prepare to defend yourself with a way of learning how to use the wheel in less time than it takes for me to make one, one that I might add is specialized to my specific task!

Comment on Get the current function used to handle control+z

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Re: Get the current function used to handle control+z by diotalevi (Canon) on Dec 14, 2008 at 05:51 UTC
The key press `Control-z` is typically mapped by your termcap or terminfo database to the capability `susp`. Your terminal interprets that and sends a SIGSTOP signal to your foreground process. SIGSTOP is 19 on the CentOS box I looked at and 17 on the Mac OS X machine I also looked at. The kill program on your *NIX takes a signal name. `kill()` in Perl doesn't though the Config module stores your local system's mapping as well. `system "kill -STOP $$"; # stop self` ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply] [d/l] [select]
Re^2: Get the current function used to handle control+z by friedo (Prior) on Dec 14, 2008 at 07:46 UTC
It's a little clunky, but you can do the `kill` from within perl by counting SIGSTOP's position in `$Config{sig_name}` (which, unfortunately, is a space-separated list rather than an array.) `perl -MConfig -le 'for( split /\s/, $Config{sig_name} ) { last if /^STOP$/; $n++ } kill $n, $$'` [download] This just counts signal names until it gets to STOP, and `$n` will contain the right number.	[reply] [d/l] [select]
Re^3: Get the current function used to handle control+z by zwon (Abbot) on Dec 14, 2008 at 11:13 UTC
There's no need to search signal number in `$Config` `kill STOP => $$;` [download] will work just fine.	[reply] [d/l]
Re: Get the current function used to handle control+z by ikegami (Patriarch) on Dec 14, 2008 at 04:53 UTC
Signals are sent using kill. `'<CONTROL+Z>' => sub { kill INT => $$ }` [download] PS — Save yourself and ourselves trouble. Use `<c>...</c>` around code and data blocks.	[reply] [d/l] [select]
Re^2: Get the current function used to handle control+z by exodist (Monk) on Dec 14, 2008 at 05:08 UTC
Thanks, however that seems to terminate the process, I want it to background the process. Maybe INT was not what I was looking for? -------------------------------------- I would rather take 30 minutes to re-invent the wheel then take 30 days to learn how to use someone else's. Before pestering me about my re-invention prepare to defend yourself with a way of learning how to use the wheel in less time than it takes for me to make one, one that I might add is specialized to my specific task!	[reply]