diff --git a/ChangeLog b/ChangeLog
index 4171fb6cc8..a12319fa91 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Mar 26 11:33:13 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/rdoc/ri/paths.rb (RDoc::RI::Paths): considers
+	  --program-prefix and --program-suffix.  reapplied r19923.
+
 Mon Mar 23 21:41:14 2009  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/dbm/dbm.c (fdbm_initialize): Make the file variable
diff --git a/lib/rdoc/ri/paths.rb b/lib/rdoc/ri/paths.rb
index 6279723529..2bcf8615e5 100644
--- a/lib/rdoc/ri/paths.rb
+++ b/lib/rdoc/ri/paths.rb
@@ -28,13 +28,20 @@ module RDoc::RI::Paths
 
   VERSION = RbConfig::CONFIG['ruby_version']
 
-  base    = File.join(RbConfig::CONFIG['datadir'], "ri", VERSION)
+  if m = /ruby/.match(RbConfig::CONFIG['RUBY_INSTALL_NAME'])
+    m = [m.pre_match, m.post_match]
+  else
+    m = [""] * 2
+  end
+  ri = "#{m[0]}ri#{m[1]}"
+  rdoc = "#{m[0]}rdoc#{m[1]}"
+  base    = File.join(RbConfig::CONFIG['datadir'], ri, VERSION)
   SYSDIR  = File.join(base, "system")
   SITEDIR = File.join(base, "site")
   homedir = ENV['HOME'] || ENV['USERPROFILE'] || ENV['HOMEPATH']
 
   if homedir then
-    HOMEDIR = File.join(homedir, ".rdoc")
+    HOMEDIR = File.join(homedir, ".#{rdoc}")
   else
     HOMEDIR = nil
   end