[itistoday]

Is there any way that I can execute some code before the a C application quits when sending it Ctrl-C?

[BLAZE_MkIV]

should be a sigalam handler right?

[itistoday]

Originally posted by BLAZE_MkIV:
should be a sigalam handler right?

Ah, don't know what a sigalam handler is, but that pointed me in the right direction. I'm no C programmer (java here), but need to know this, so apparently it's called "signal handling". I found myself a nice tutorial thanks.

[proton]

I believe you'll find it's SIGINT not SIGALRM.

- proton

[geran]

I got a small exemple that catch a Ctrl C signal. It small and should be easy to understand.

you can d/l it from:

http://www.cs.umu.se/~dv02mgn/sigtest.c
http://www.cs.umu.se/~dv02mgn/sig.c
http://www.cs.umu.se/~dv02mgn/sig.h

conmpiles whit:

gcc -Wall -pedantic -o sigtest sigtest.c sig.c

execute with

./sigtest

it sets upp the signal handler and loops forever, press ctrl c to exit. If you look in the sig.c file, the ctrlC function is executed when a SIGINT (ctrl c) signal is sent.

hope it helps.

[holygoat]

Code:
// Signal handler function.
void handleSignal(int signum) {
        switch(signum) {
                case SIGHUP:
                        printf("Caught signal HUP, quitting...");
                        break;
                case SIGQUIT:
                        printf("Quitting...");
                        break;
                case SIGINT:
                        printf("Interrupted, quitting...");
                        break;
                default:
                        printf("Catching signal %i, quitting...", signum);
        }
        // Shutdown gracefully.           
        exit(0);
}
// Register signal handlers for common signals.
void registerSignalHandlers() { 
        signal(SIGHUP, handleSignal);
        signal(SIGQUIT, handleSignal);
        signal(SIGINT, handleSignal);
        signal(SIGABRT, handleSignal);
}

Just call registerSignalHandlers() somewhere at the start of your program, and fill in what you want to do where I've put the printf statements.

[Angus_D]

Note that there are very few functions that are safe to call from signal handlers.

[itistoday]

Thanks everyone for the great help!