From b6f7c57ecf2fcefa805b1cebb1751d5fecd1ddfe Mon Sep 17 00:00:00 2001
From: Colin Percival <cperciva@FreeBSD.org>
Date: Sun, 18 Apr 2004 23:36:45 +0000
Subject: Document POSIX stupidity: Attempts to mmap zero bytes will succeed
 (and have no effect), while attempts to munmap zero bytes will fail.

---
 lib/libc/sys/mmap.2 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/libc/sys/mmap.2 b/lib/libc/sys/mmap.2
index f7fd62dd4efd..8d6cfd76dfe7 100644
--- a/lib/libc/sys/mmap.2
+++ b/lib/libc/sys/mmap.2
@@ -363,3 +363,10 @@ the file system code that causes the limit to be further restricted to
 .Pp
 Another reason for the 2GB limit is that file system metadata can
 reside at negative offsets.
+.Pp
+Note that an attempt to
+.Fn mmap
+zero bytes has no effect and succeeds, while an attempt to
+.Fn munmap
+zero bytes will return
+.Bq Er EINVAL .
-- 
cgit v1.3