Hands-On System Programming with Linux

Running of case 1 – SA_NODEFER bit cleared [default]

Next, we execute the test case wherein the SA_NODEFER flag is cleared; this is the default behavior:

$ ./defer_or_not Usage: ./defer_or_not {option}option=1 : don't use (clear) SA_NODEFER flag (default sigaction style)option=2 : use (set) SA_NODEFER flag (will process signal immd)$ ./defer_or_not 1PID 3016: running with the SA_NODEFER signal flag Cleared [default]Process awaiting signals ...

Now, in another terminal window, we run the shell script:

$ ./bombard_sig.sh $(pgrep defer_or_not) 12

The pgrep figures out the PID of the defer_or_not process: useful! Just ensure the following: (a) Only one instance of the process you are sending signals to is alive, or pgrep returns multiple PIDs ...