minor update to thread-join docs

diff --git a/doc/lispref/threads.texi b/doc/lispref/threads.texi
index 434915cdbc20d44d92f944b35ae58882464647f9..5c4c62f2c06a2a4ef8d145a7ff2a9d1cfae28c7b 100644 (file)
--- a/doc/lispref/threads.texi
+++ b/doc/lispref/threads.texi
@@ -67,7 +67,9 @@ thread, @code{nil} otherwise.
 @end defun
 
 @defun thread-join thread
-Block until @var{thread} exits, or until the current thread is signaled.
+Block until @var{thread} exits, or until the current thread is
+signaled.  If @var{thread} has already exited, this returns
+immediately.
 @end defun
 
 @defun thread-signal thread error-symbol data