diff --git a/ChangeLog b/ChangeLog
index 2317f8bcf5..c098e11d38 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Apr 25 01:18:43 2005  Tanaka Akira  <akr@m17n.org>
+
+        * oniguruma.h (OnigWarnFunc): add a variadic argument.
+	[ruby-core:4751]
+
 Sat Apr 23 19:49:21 2005  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
 
 	* ext/tk/tcltklib.c (ip_RubyExitCommand): exit with status code
diff --git a/oniguruma.h b/oniguruma.h
index ef448cc698..95dfbebc5f 100644
--- a/oniguruma.h
+++ b/oniguruma.h
@@ -704,8 +704,8 @@ typedef struct {
   int upper;
 } OnigRepeatRange;
 
-typedef void (*OnigWarnFunc) P_((const char* s));
-extern void onig_null_warn P_((const char* s));
+typedef void (*OnigWarnFunc) P_((const char* s, ...));
+extern void onig_null_warn P_((const char* s, ...));
 #define ONIG_NULL_WARN       onig_null_warn
 
 #define ONIG_CHAR_TABLE_SIZE   256
diff --git a/regparse.c b/regparse.c
index 04a0ccea5b..0d8f5bc0bb 100644
--- a/regparse.c
+++ b/regparse.c
@@ -58,7 +58,7 @@ OnigSyntaxType OnigSyntaxRuby = {
 
 OnigSyntaxType*  OnigDefaultSyntax = ONIG_SYNTAX_RUBY;
 
-extern void onig_null_warn(const char* s) { }
+extern void onig_null_warn(const char* s, ...) { }
 
 #ifdef DEFAULT_WARN_FUNCTION
 static OnigWarnFunc onig_warn = (OnigWarnFunc )DEFAULT_WARN_FUNCTION;