(add-hook): Doc fix.

diff --git a/lisp/subr.el b/lisp/subr.el
index c87bc90136c3782e303d9000a517176924f22a56..3ff0f96afcf6586b846267383debdf5e0b7ddaf4 100644 (file)
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -734,7 +734,9 @@ FUNCTION is added at the end.
 
 The optional fourth argument, LOCAL, if non-nil, says to modify
 the hook's buffer-local value rather than its default value.
-This makes the hook buffer-local if needed.
+This makes the hook buffer-local if needed, and it makes t a member
+of the buffer-local value.  That acts as a flag to run the hook
+functions in the default value as well as in the local value.
 
 HOOK should be a symbol, and FUNCTION may be any valid function.  If
 HOOK is void, it is first set to nil.  If HOOK's value is a single