From 00a1fbcfc46fa9f542dd4d689bf2d2f9b7274114 Mon Sep 17 00:00:00 2001
From: Michael Kerrisk <mtk.manpages@gmail.com>
Date: Mon, 26 Nov 2012 05:25:00 +0100
Subject: [PATCH] wait.2: BUGS: Document odd waitid() behavior when 'infop' is
 NULL

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/wait.2 | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/man2/wait.2 b/man2/wait.2
index df015139b..7f466b88e 100644
--- a/man2/wait.2
+++ b/man2/wait.2
@@ -602,6 +602,21 @@ main(int argc, char *argv[])
     }
 }
 .fi
+.SH BUGS
+According to POSIX.1-2008, an application calling
+.BR waitid ()
+must ensure that
+.I infop
+points to a
+.I siginfo_t
+structure (i.e., that it is a non-NULL pointer).
+On Linux, if
+.I infop
+is NULL,
+.BR waitid ()
+succeeds, and returns the process ID of the waited-for child.
+Applications should avoid relying on this inconsistent,
+nonstandard, and unnecessary feature.
 .SH "SEE ALSO"
 .BR _exit (2),
 .BR clone (2),