diff --git a/ChangeLog b/ChangeLog
index 341277d1b4..cbe29c617c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+Mon Jun 23 23:59:56 2003  Minero Aoki  <aamine@loveruby.net>
+
+	* io.c (io_close): missing prototype.
+
+	* ext/socket/socket.c (bsock_do_not_rev_lookup_set): ditto.
+
+	* ext/win32ole/win32ole.c (foletype_guid, foletype_progid): ditto.
+
+	* error.c (syserr_initialize): length argument of sprintf() is an
+	  int.
+
 Mon Jun 23 23:28:14 2003  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* MANIFEST: add wince files.
diff --git a/error.c b/error.c
index f62150f3e5..901d0f0273 100644
--- a/error.c
+++ b/error.c
@@ -582,7 +582,7 @@ syserr_initialize(argc, argv, self)
     if (!NIL_P(mesg)) {
 	StringValue(mesg);
 	buf = ALLOCA_N(char, strlen(err)+RSTRING(mesg)->len+4);
-	sprintf(buf, "%s - %.*s", err, RSTRING(mesg)->len, RSTRING(mesg)->ptr);
+	sprintf(buf, "%s - %.*s", err, (int)RSTRING(mesg)->len, RSTRING(mesg)->ptr);
 	mesg = rb_str_new2(buf);
     }
     else {
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index 0198a8e1d6..87ca9b874a 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -484,6 +484,7 @@ bsock_do_not_rev_lookup()
 
 static VALUE
 bsock_do_not_rev_lookup_set(self, val)
+    VALUE self, val;
 {
     rb_secure(4);
     do_not_reverse_lookup = RTEST(val);
diff --git a/ext/win32ole/win32ole.c b/ext/win32ole/win32ole.c
index c738063aa8..b8b5bcf471 100644
--- a/ext/win32ole/win32ole.c
+++ b/ext/win32ole/win32ole.c
@@ -3190,6 +3190,7 @@ ole_type_guid(pTypeInfo)
  */
 static VALUE
 foletype_guid(self)
+    VALUE self;
 {
     struct oletypedata *ptype;
     Data_Get_Struct(self, struct oletypedata, ptype);
@@ -3221,6 +3222,7 @@ ole_type_progid(pTypeInfo)
  */
 static VALUE
 foletype_progid(self)
+    VALUE self;
 {
     struct oletypedata *ptype;
     Data_Get_Struct(self, struct oletypedata, ptype);
diff --git a/io.c b/io.c
index 1377df4b51..956d698511 100644
--- a/io.c
+++ b/io.c
@@ -1424,6 +1424,7 @@ rb_io_close_m(io)
 
 static VALUE
 io_close(io)
+    VALUE io;
 {
     return rb_funcall(io, rb_intern("close"), 0, 0);
 }