[TheDong]

You also need to specifically have the subreaper process call the "wait" syscall, and wait for all children, otherwise of course they'll end up reparented to init.

If you want to write a process manager, one of the process manager's responsibilities is waiting on its children.

[ComputerGuru]

Just a nitpick: They don’t get reparented to init regardless of whether you call wait or not, so long as the parent process exists. They’ll be in a zombie state waiting to be reaped via a parent call to wait. Only if the parent dies/exits without reaping will they be reparented to init.