diff --git a/ChangeLog b/ChangeLog
index 78a589884f..96adb4ef91 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jul 23 14:19:17 2003  Nobuyoshi Nakada  <nobu.nokada@softhome.net>
+
+	* lib/mkmf.rb (log_src, checking_for, create_header):
+	  Logging.message is printf like format.
+
 Wed Jul 23 10:11:15 2003  Nobuyoshi Nakada  <nobu.nokada@softhome.net>
 
 	* ext/iconv/iconv.c (check_iconv): check if Iconv instance.
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index f9e9a35533..513e7683b5 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -169,10 +169,10 @@ def xpopen command, *mode, &block
 end
 
 def log_src(src)
-  Logging::message <<"EOM"
+  Logging::message <<"EOM", src
 checked program was:
 /* begin */
-#{src}/* end */
+%s/* end */
 
 EOM
 end
@@ -363,11 +363,11 @@ end
 def checking_for(m)
   f = caller[0][/in `(.*)'$/, 1] and f << ": " #` for vim
   m = "checking for #{m}... "
-  message m
-  Logging::message "#{f}#{m}--------------------\n"
+  message "%s", m
+  Logging::message "%s%s--------------------\n", f, m
   r = yield
   message(a = r ? "yes\n" : "no\n")
-  Logging::message "-------------------- #{a}\n"
+  Logging::message "-------------------- %s\n", a
   r
 end
 
@@ -481,7 +481,7 @@ def enable_config(config, default=nil)
 end
 
 def create_header(header = "extconf.h")
-  message "creating #{header}\n"
+  message "creating %s\n", header
   if $defs.length > 0
     sym = header.tr("a-z./\055", "A-Z___")
     open(header, "w") do |hfile|