On Sat, May 7, 2016, at 02:43 PM, Christian Seiler wrote:
>
> No, it does catch the signal without a problem. But start-stop-daemon
> closes the standard filedescriptors and replaces them with /dev/null.
>
> Try it:
>
> /tmp/t.sh start
> ps ax | grep a.out
> lsof -p $PID
> -> look for FD = 0u, 1u and 2u, those are all /dev/null
>
> That means that the error output is dropped, because it goes to
> /dev/null.
>
> If you alter your test code to include #include <fstream> and replace
> the following function:
>
> void signal_handler(int signal_number)
> {
> std::ofstream error_out("/tmp/daemon-error.out");
> error_out << "Caught signal# " << signal_number << std::endl;
> caught_signal=signal_number;
> }
>
> Then you will see that /tmp/daemon-error.out is generated and that
> there is the text "Caught signal#15" inside, if you terminate the
> daemon via the init script.
>
Dear Christian,
You have saved me from resorting to debuggers after days' fruitless
digging.
Big thanks to your kind enlightenment!
Best regards,
CN
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