Will ctrl+c send SIGINT signals to both parent and child processes in Linux?

Question

In the terminal, I executed a main parent process which will fork a child process. In both the parent and child processes I implemented a SIGINT signal handler. So when I press "ctrl+c", will both the handlers be called at the same time? Or do I need to call the child process's signal handler explicitly in the parent process's handler?

I looked up this post: How does Ctrl-C terminate a child process? which says that "The SIGINT signal is generated by the terminal line discipline, and broadcast to all processes in the terminal's foreground process group". I just didn't quite understand what does "foreground process group" means.

Thanks,

Answer 1

In both the parent and child processes I implemented a SIGINT signal handler. So when I press "ctrl+c", will both the handlers be called at the same time?

Yes, they both will receive SIGINT.

Or do I need to call the child process's signal handler explicitly in the parent process's handler?

"Calling" another process' signal handler doesn't make sense. If the both the process have a handler installed then they will be called once they receive the signal SIGINT.

I just didn't quite understand what does "foreground process group" means.

Typically, a process associated with a controlling terminal is foreground process and its process group is called foreground process group. When you start a process from the command line, it's a foreground process:

E.g.

$ ./script.sh # foreground process
$ ./script & # background process

I suggest you read about tty and The TTY demystified for a detailed explanation.