c - 创建守护进程时离开调用 setsid() 有什么影响？

Question

守护进程时不调用 setsid() 有什么危险？

Answer 1

When a user logs out from a session, all processes associated with that session are killed. For processes that are daemons you do not want this to happen. The solution is to call setsid. Provided that the daemon is not already a process group leader (which it will not be following the fork performed above), this will:

1. start a new session, with the daemon as session leader and with no controlling terminal, and
2. start a new process group, with the daemon as process group leader.

来自 here

所以基本上，如果你不给它一个新的 session ID，它可能会被无意中杀死。