CODEWITHSUNDEEP
clinuxterminalsystem-calls
Simplex
Simplex

Reputation: 1733

Why are all processes killed when a terminal session ends?

Not long ago, I wondered about the question: why are all processes killed when you close a terminal on Linux, and not passed to the "init" process (with pid 1)? Because, all child processes are adopted by "init" process after termination of the parent. Please, help me understand difference and the errors in my reasoning.

And also: If it's possible, then can we use a system call to stop this happening? I think, that for this the programs need use setsid(), but in practice it's not correct.

Upvotes: 1

Views: 652

Answers (3)

Jens
Jens

Reputation: 72639

As explained by cnicutar, it's due to the SIGHUP sent to all processes in the process group associated with the controlling terminal. You may either install a handler for this signal or ignore it completely. For arbitrary programs, you can start them with the nohup utility designed for this purpose.

You can also place the process in a new process group without a controlling terminal.

Upvotes: 2

Charan Pai
Charan Pai

Reputation: 2318

i think this will help you to understand http://www.digipedia.pl/usenet/thread/18802/10189/

Upvotes: 0

cnicutar
cnicutar

Reputation: 182619

why on close terminal on linux all his processes will terminated, but not passed to "init" process (with pid 1)

The processes are losing their controlling terminal so the kernel sends them a SIGHUP. The default action of SIGHUP is to terminate the process.

Upvotes: 1

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