diff --git a/src/buffer.h b/src/buffer.h
index 403b249df6f..986cc6fbede 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -1457,7 +1457,9 @@ BUF_FETCH_CHAR_AS_MULTIBYTE (struct buffer *buf, ptrdiff_t pos)
 	  : UNIBYTE_TO_CHAR (BUF_FETCH_BYTE (buf, pos)));
 }
 
-/* Return number of windows showing B.  */
+/* Return number of windows showing B or a buffer that has B as its base
+   buffer.  If B is an indirect buffer, this returns buffer_window_count
+   of its base buffer.  */
 
 INLINE int
 buffer_window_count (struct buffer *b)