Module death_pipe 

Functions

close_fd

create_death_pipe

Create a pipe for parent-death detection. Returns (read_fd, write_fd). Neither end has CLOEXEC set. Parent holds write_fd open. Child monitors read_fd for POLLHUP.

spawn_death_watcher

Monitor a death pipe FD in a background thread. When the write end closes (parent dies), POLLHUP fires and running is set to false, triggering the probe’s graceful shutdown.