C<getppid()> return different values from different threads. In order to
be portable, this behavior is not reflected by the perl-level function
C<getppid()>, that returns a consistent value across threads. If you want
-to call the underlying C<getppid()>, consider using C<Inline::C> or
-another way to call a C library function.
+to call the underlying C<getppid()>, you may use the CPAN module
+C<Linux::Pid>.
=item getpriority WHICH,WHO