From da83e8a2379f78358aed86258691df6fae64048b Mon Sep 17 00:00:00 2001
From: Michael Kerrisk <mtk.manpages@gmail.com>
Date: Thu, 26 Mar 2015 09:09:16 +0100
Subject: [PATCH] getpid.2: Note that getppid() returns 0 if parent is in
 different PID namespace

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/getpid.2 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/man2/getpid.2 b/man2/getpid.2
index a5bf582b9..9c5f3d71d 100644
--- a/man2/getpid.2
+++ b/man2/getpid.2
@@ -46,6 +46,11 @@ These functions are always successful.
 .SH CONFORMING TO
 POSIX.1-2001, 4.3BSD, SVr4.
 .SH NOTES
+If the caller's parent is in a different PID namespace (see
+.BR pid_namespaces (7)),
+.BR getppid ()
+returns 0.
+.\"
 .SS C library/kernel ABI differences
 Since glibc version 2.3.4,
 the glibc wrapper function for