How to get all descendent child process id of pid in c in linux [duplicate]

Question

This question already has answers here:

How to get child process from parent process (11 answers)

Closed 8 years ago.

If I fork and the child process then exec and creates more child processes (which themselves can create more processes) , how do I get a list of pids of all the descendent process from the first process?

Is there a better way then looping though /proc/ and checking the PPid (the parent of process's id) of each of process?

Answer 1

Iterating through /proc is the "standard" way to do this. That's how ps and friends (pstree, etc.) are implemented.

Answer 2

If you are looking for commands to see the process tree, check below commands.

ps -ejH
ps axjf
pstree $PID

Check the man pages of ps and pstree commands.