diff --git a/ChangeLog b/ChangeLog
index 98bd809012..b4bbe7b9b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Oct 29 11:50:57 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (dln-a-out): cannot make shared library nor work with
+	  ELF.  [ruby-core:19571]
+
 Wed Oct 29 11:00:25 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.c (rb_w32_open): shouldn't seek here.
diff --git a/configure.in b/configure.in
index dfa495bee6..83e76711df 100644
--- a/configure.in
+++ b/configure.in
@@ -1253,7 +1253,13 @@ dnl wheather use dln_a_out or not
 AC_ARG_WITH(dln-a-out, 
 	[  --with-dln-a-out        use dln_a_out if possible], [
 	case $withval in
-	yes) with_dln_a_out=yes;;
+	dnl (
+	yes)
+	    if test "$enable_shared" = yes; then
+		AC_MSG_ERROR(dln_a_out can not make shared library)
+	    fi
+	    with_dln_a_out=yes;;
+	dnl (
 	*)   with_dln_a_out=no;;
 	esac], [with_dln_a_out=no])
 
@@ -1271,6 +1277,9 @@ rb_cv_binary_elf=no)])
 
 if test "$rb_cv_binary_elf" = yes; then
   AC_DEFINE(USE_ELF)
+  if test "$with_dln_a_out" = yes; then
+    AC_MSG_ERROR(dln_a_out does not work with ELF)
+  fi
 fi
 
 case "$target_os" in