Is there anyway to pass arguments to a signal handler? [duplicate]

Question

I'm registering in the main an handler for the SIGTERM like this:

signal(SIGTERM, sigterm_handler);

And the handler is a simple:

void sigterm_handler()
{    exit(1);    }

What if I need to pass to the handler a few arguments like a 2 pointers or anything else? How do I register the handler in the signal function? Or at least... is there anyway to achieve that?

Notice: the process is killed by a third party process, not by itself. But before closing I need to manually free some structures and write them on files.

Answer 1

Where do you intend to pass the arguments from? The only time sending a signal would be a reasonable way to do what you're doing is when the process you're terminating is not the process itself, but in that case, pointers would be meaningless. You can pass a pointer with the sigqueue function and SA_SIGINFO type signal handlers, but it looks to me like you don't understand signals or have any good reason for using them in the first place. Just make a function call when you want to exit rather than raising signals...

Answer 2

Simply use a global variable. As others have pointed out, your signal handler will be invoked by a call stack not under your control.

You might consider using setjmp() and longjmp() to transfer control from your signal handler to a previously-executed code path. This old-school approach could be really fun for you.