diff --git a/man7/sem_overview.7 b/man7/sem_overview.7
index 6575a3e43..d2c6c2762 100644
--- a/man7/sem_overview.7
+++ b/man7/sem_overview.7
@@ -23,7 +23,7 @@
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
 .\"
-.TH SEM_OVERVIEW 7 2008-06-15 "Linux" "Linux Programmer's Manual"
+.TH SEM_OVERVIEW 7 2009-02-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 sem_overview \- Overview of POSIX semaphores
 .SH DESCRIPTION
@@ -44,7 +44,20 @@ unnamed semaphores.
 .TP
 .B Named semaphores
 A named semaphore is identified by a name of the form
-.IR /somename .
+.IR /somename ;
+that is, a null-terminated string of up to
+.BI NAME_MAX +1
+(i.e., 256) characters consisting of an initial slash,
+.\" glibc allows the initial slash to be omitted, and makes
+.\" multiple initial slashes equivalent to a single slash.
+.\" This differs from the implementation of POSIX message queues.
+followed by one or more characters, none of which are slashes.
+.\" glibc allows subdirectory components in the name, in which
+.\" case the subdirectory tree must exist under /dev/shm, and
+.\" the fist subdirectory component must exist as the name
+.\" sem.name, and all of the subdirectory components must allow the
+.\" required permissions if a user wants to create a semaphore
+.\" object in a subdirectory.
 Two processes can operate on the same named semaphore by passing
 the same name to
 .BR sem_open (3).
@@ -113,7 +126,7 @@ On Linux, named semaphores are created in a virtual file system,
 normally mounted under
 .IR /dev/shm ,
 with names of the form
-.IR \fBsem.\fPname .
+.IR \fBsem.\fPsomename .
 
 Since Linux 2.6.19, ACLs can be placed on files under this directory,
 to control object permissions on a per-user and per-group basis.