When the system supports it (as all Linux kernels ≥ 5.3 should), it’s
preferable to use pidfd_open() and waitid() to be notified of
child processes exiting or being signalled, rather than installing a
default SIGCHLD handler.
A default SIGCHLD handler is global, and can never interact well with
other code (from the application or other libraries) which also wants to
install a SIGCHLD handler.
This use of pidfd_open() is racy (the PID may be reused between
g_child_watch_source_new() being called and pidfd_open() being
called), so it doesn’t improve behaviour there. For that, we’d need
continuous use of pidfds throughout GLib, from fork/spawn time until
here. See #1866 for that.
Signed-off-by: Philip Withnall pwithnall@endlessos.org
Closes #2216