How to kill a process and all of its descendants in Nim?

[mrhdias]

I replicated the following code from a python program to nim to create 
processes via fork. But how to do to kill all processes (parent and child's) at 
once?
    
    
    import posix
    import os
    
    proc parent_child(p = 0) =
      while true:
        echo "Process: ", p
        sleep(1000)
    
    proc main() =
      var children: seq[Pid]
      let forks = 3
      
      for f in 0 .. forks - 1:
        let pid = fork()
        if pid < 0:
          # error forking a child
          quit(QuitFailure)
        elif pid > 0:
          let p = getpid()
          echo "In parent process: ", int(p)
          children.add(pid)
        else:
          let p = getpid()
          echo "In child process: ", int(p)
          parent_child(f)
          quit()
      
      
      for child in children:
        var status: cint
        discard waitpid(child, status, 0)
    
    main()
    
    
    Run