diff --git a/ChangeLog b/ChangeLog
index ead1f75999..55172778dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Mar 22 00:50:33 2010  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/rubysocket.h (rsock_revlookup_flag): declared.
+
 Mon Mar 22 00:01:24 2010  Alexander Zavorine  <alexandre.zavorine@nokia.com>
 
 	* symbian/setup (config.h): RUBY_EXEC_PREFIX defined.
diff --git a/ext/socket/rubysocket.h b/ext/socket/rubysocket.h
index 2159e74d8c..c5b8cd7aa9 100644
--- a/ext/socket/rubysocket.h
+++ b/ext/socket/rubysocket.h
@@ -218,6 +218,8 @@ VALUE rsock_make_ipaddr(struct sockaddr *addr);
 VALUE rsock_ipaddr(struct sockaddr *sockaddr, int norevlookup);
 VALUE rsock_make_hostent(VALUE host, struct addrinfo *addr, VALUE (*ipaddr)(struct sockaddr *, size_t));
 
+int rsock_revlookup_flag(VALUE revlookup, int *norevlookup);
+
 #ifdef HAVE_SYS_UN_H
 const char* rsock_unixpath(struct sockaddr_un *sockaddr, socklen_t len);
 VALUE rsock_unixaddr(struct sockaddr_un *sockaddr, socklen_t len);