Index: file.c
===================================================================
--- file.c	(revision 37088)
+++ file.c	(working copy)
@@ -3830,7 +3830,7 @@
  *     File.extname(path)  ->  string
  *
  *  Returns the extension (the portion of file name in <i>path</i>
- *  after the period).
+ *  starting from the last period).
  *
  *     File.extname("test.rb")         #=> ".rb"
  *     File.extname("a/b/d/test.rb")   #=> ".rb"