CODEWITHSUNDEEP
linuxsignals
Topilski Alexandr
Topilski Alexandr

Reputation: 669

Why i can't catching SIGINT signal?

Good day, i have next code:

server s;
namespace signals_handler
{
    //sig_atomic_t is_stop=0;
    void signal_handler(int sig)
    {
        if(sig==SIGHUP)
        {
            printf("recived :SIGHUP\n");
            s.restart();
        }
        else if(sig==SIGINT)
        {
            printf("recived :SIGINT\n");
            //is_stop = 1;
            s.interupt();
        }
    }
}
int main(int argc, char* argv[])
{
    signal(SIGHUP, signals_handler::signal_handler);
    signal(SIGINT, signals_handler::signal_handler);
    s.start();
    s.listen();
    return 0;
}

When i start execution of this code i can to catch SIGHUP, SIGINT not deliver for my application but debugger stoped in the "listen" function but not move to signalhandler function, Why this happens and what i doing wrongly?

Upvotes: 0

Views: 1054

Answers (1)

Karoly Horvath
Karoly Horvath

Reputation: 96258

It's normal. gdb catches the signal. From the manual:

Normally, gdb is set up to let the non-erroneous signals like SIGALRM be silently passed to your program (so as not to interfere with their role in the program's functioning) but to stop your program immediately whenever an error signal happens. You can change these settings with the handle command.

To change the behaviour, use:

handle SIGINT nostop pass

handle signal [keywords...] Change the way gdb handles signal signal. signal can be the number of a signal or its name (with or without the ‘SIG’ at the beginning); a list of signal numbers of the form ‘low-high’; or the word ‘all’, meaning all the known signals. Optional arguments keywords, described below, say what change to make.

The keywords allowed by the handle command can be abbreviated. Their full names are:

nostop
    gdb should not stop your program when this signal happens. It may still print a message telling you that the signal has come in.
stop
    gdb should stop your program when this signal happens. This implies the print keyword as well.
print
    gdb should print a message when this signal happens.
noprint
    gdb should not mention the occurrence of the signal at all. This implies the nostop keyword as well.
pass
noignore
    gdb should allow your program to see this signal; your program can handle the signal, or else it may terminate if the signal is fatal and not handled. pass and noignore are synonyms.
nopass
ignore
    gdb should not allow your program to see this signal. nopass and ignore are synonyms.

Upvotes: 1

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