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I have a (C, Linux) application which handles Ctrl-C SIGINT by shutting down. I'd like to add another signal handler so that I can use another keystroke combo for "reload configuration while running".

So I'm looking from a signal I can send to the foreground process by keystroke, which doesn't force the process to quit or suspend. Are there any others?

blueshift
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3 Answers3

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You can use ctrl+Z,

SIGTSTP

Value = 20

For more details refer this link.

Anantha Krishnan
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4

You can try Ctrl - \ which is SIGQUIT if you absolutely need it to be a keystroke (you can catch it).

cnicutar
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Your program can use SIGUSR1 and SIGUSR2 to do whatever it wants, but there's no single-stroke way of sending them like how a Ctrl+C sends a SIGINT signal. You have to use something like kill(1) to send the signal, e.g. kill -USR1 <mypid>.

Adam Rosenfield
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    Correct, so that's not what I want. – blueshift Mar 30 '12 at 06:07
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    @blueshift But keep in mind that those are the signals you are _supposed_ to handle. By changing the others you are creating unexpected behavior. This is not necessarily bad unless you are distributing the program. – Aaron Dufour Mar 30 '12 at 06:13
  • A fair point. But this is internal only, embedded system, not a problem. – blueshift Mar 30 '12 at 06:17
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    It is a shame. SIGUSR1 and SIGUSR2 are precisely the signals that we can handle better and would be very useful to have keyboard shortcuts for them. – yucer Mar 11 '17 at 05:34