how to get pid of a process which issued a signal

[FrankMacri]

hi, there exists a way to get the pid of a process which issued a signal?

because I'm writing a little shell where there are several processes running in the background, so I need to know which process has issued a SIGCHLD

regards

frank

[Rubberman]

It won't tell you what the signal was that terminated it, but you can execute the wait command in a bash shell which will return the pid of a terminating child process. If you are running a C/C++ program, then the wait() function basically does the same thing.

[FrankMacri]

yes, I already knew it. The problem is that for my purpose this solution does not work, since I made the backgrounds processes as processes which are not waited from the parent, and so the wait() is done only for the foreground processes.
Sadly now the parent never waits for the backgrounds ones, neither when they have finished. So I'm trying to implement a sigchld handler in order to allow the shell to wait also for those into bg, but I have no way to know which process has issued the sig, and so I can't know if the process signaled is a bg one, and so it has to perform wait() yet, or if it is a foreground one, so it should not wait again, since it has already waited. Otherwise I get two waits and it's not very useful

There are no other ways?

regards