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authorColin Percival <cperciva@FreeBSD.org>2004-04-18 23:36:45 +0000
committerColin Percival <cperciva@FreeBSD.org>2004-04-18 23:36:45 +0000
commitb6f7c57ecf2fcefa805b1cebb1751d5fecd1ddfe (patch)
tree07ef1e76c8def16be1b199656e49826a43005d9f /lib
parent076419d2073e67d516cb96f8b837ac6cfa754624 (diff)
downloadsrc-b6f7c57ecf2fcefa805b1cebb1751d5fecd1ddfe.tar.gz
src-b6f7c57ecf2fcefa805b1cebb1751d5fecd1ddfe.zip
Document POSIX stupidity: Attempts to mmap zero bytes will succeed (and
have no effect), while attempts to munmap zero bytes will fail.
Notes
Notes: svn path=/head/; revision=128411
Diffstat (limited to 'lib')
-rw-r--r--lib/libc/sys/mmap.27
1 files changed, 7 insertions, 0 deletions
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 .