Question

My signal handler looks like:

volatile sig_atomic_t loop     = 1;

void handle()
{
    loop = 0;
}

And, I have a daemon which is like:

void _start_()
{
...
sa.sa_handler = handle;
sigaction(SIGINT, &sa, NULL);
while(loop)
{
   //add a line to a file
}
...
}

I want to stop the daemon, from another function like:

void _stop_()
{
    raise(SIGINT);
}

My idea is, somehow if the value of loop is 0, then the while would be evaluated as false, and the daemon exits.
I am planning to use these two functions like:

_start_(); //daemon starts
//computation
_stop_() //daemon stops writing to the file. exits

How can I achieve this? The problem is I am not able to stop the daemon from _stop_().

Thanks

Answer 1

Is the _stop() function called from a separate process from your daemon? If so, then it needs to know the ID of the process to signal. Normal practice is that the daemon writes its process ID to a file (a PID file) which can the be read by the process that stops the daemon.