As long as a pidfd is on a child it can be safely reaped. Taking it would mean the child would now have to be awaited through its pid, but could also be awaited through the pidfd. This could then suffer from a recycling race.
Unix{Datagram,Stream}::{set_}passcred()
tcp_deferaccept
{As,Borrowed,Owned}Fd
std::os::solid::prelude
size_of
size_of_val
align_of
align_of_val
io::Error