in reply to Get the current function used to handle control+z

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

⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊