How can I catch a ctrl-c event? (C++)

Question

How do I catch a ctrl-c event in C++?

Answer 1

You have to catch the SIGINT signal (we are talking POSIX right?)

See @Gab Royer´s answer for sigaction.

Example:

#include <signal.h>
#include <stdlib.h>
#include <stdio.h>

void my_handler(sig_t s){
           printf("Caught signal %d\n",s);
           exit(1); 

}

int main(int argc,char** argv)
{
   signal (SIGINT,my_handler);

   while(1);
   return 0;

}

Answer 2

IMHO it's platform dependent.

Answer 3

signal isn't the most reliable way as it differs in implementations. I would recommend using sigaction. Tom's code would now look like this :

#include <signal.h>
#include <stdlib.h>
#include <stdio.h>

void my_handler(sig_t s){
           printf("Caught signal %d\n",s);
           exit(1); 

}

int main(int argc,char** argv)
{

   struct sigaction sigIntHandler;

   sigIntHandler.sa_handler = my_handler;
   sigemptyset(&sigIntHandler.sa_mask);
   sigIntHandler.sa_flags = 0;

   sigaction(SIGINT, &sigIntHandler, NULL);

   while(1);
   return 0;

}

Answer 4

Yeah, this is a platform dependent question.

If you are writing a console program on POSIX, use the signal API (#include <signal.h>).

In a WIN32 GUI application you should handle the WM_KEYDOWN message.

Answer 5

For a Windows console app, you want to use SetConsoleCtrlHandler to handle CTRL+C and CTRL+BREAK.

See here for an example.

Answer 6

For whatever it's worth, here's how I did it in my program:

  QChar chr(getch());
  if(chr == 3)
  {
    emit sigCtrlC();
  }

I tested it, and it works.

Answer 7

Can anybody help me? how can I do catch a CTRL+X event. CTRL+X should terminate (kill) all tasks except task 0 (shell) <<-- it's my homework(((. thanks