Why none any signals raised on application exited NORMALLY?

Question

I write a library, register signal handler in function that application always called. I register following signals:

• SIGQUIT
• SIGINT
• SIGKILL
• SIGCHLD
• SIGHUP
• SIGSTOP
• SIGTERM

All signal handlers point to same function just like that:

signal(SIGQUIT,signal_handler);
signal(SIGINT,signal_handler);
signal(SIGKILL,signal_handler);
....

When I run the application, and exited NORMALLY, there aren't any signals raised at all. But if I break it with <ctrl-c>, SIGINT will raised and my signal handler is triggered,too. Why aren't any signals raised when the application exited normally?

Answer 1

Because that's how it works. Signals are only raised when something abnormal happens.

If you want to run something when the program exits normally, try using atexit() or on_exit().