From a63243b9e2ae4c704b3a781bc35a802be41d7dd9 Mon Sep 17 00:00:00 2001
From: Michael Kerrisk <mtk.manpages@gmail.com>
Date: Tue, 25 Feb 2020 16:29:19 +0100
Subject: [PATCH] msgctl.2: Add information on permission bits (based on
 sysvipc(7) text)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/msgctl.2 | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/man2/msgctl.2 b/man2/msgctl.2
index ac59ff862..753f68aca 100644
--- a/man2/msgctl.2
+++ b/man2/msgctl.2
@@ -139,6 +139,24 @@ struct ipc_perm {
 .EE
 .in
 .PP
+The least significant 9 bits of the
+.I mode
+field of the
+.I ipc_perm
+structure define the access permissions for the message queue.
+The permission bits are as follows:
+.TS
+l l.
+0400	Read by user
+0200	Write by user
+0040	Read by group
+0020	Write by group
+0004	Read by others
+0002	Write by others
+.TE
+.PP
+Bits 0100, 0010, and 0001 (the execute bits) are unused by the system.
+.PP
 Valid values for
 .I cmd
 are: