diff --git a/ext/pg.c b/ext/pg.c
index a2dd359e0..c2e2ef289 100644
--- a/ext/pg.c
+++ b/ext/pg.c
@@ -125,7 +125,7 @@ const char * const (pg_enc_pg2ruby_mapping[][2]) = {
  * - returns NULL if the client encoding is 'SQL_ASCII'.
  * - returns ASCII-8BIT if the client encoding is unknown.
  */
-rb_encoding *
+static rb_encoding *
 pg_get_pg_encoding_as_rb_encoding( int enc_id )
 {
 	const char *name = pg_encoding_to_char( enc_id );
diff --git a/ext/pg.h b/ext/pg.h
index f5c8e9fe6..744a090aa 100644
--- a/ext/pg.h
+++ b/ext/pg.h
@@ -369,7 +369,6 @@ pgresult_get_this( VALUE self )
 }
 
 
-rb_encoding * pg_get_pg_encoding_as_rb_encoding        _(( int ));
 rb_encoding * pg_get_pg_encname_as_rb_encoding         _(( const char * ));
 const char * pg_get_rb_encoding_as_pg_encoding         _(( rb_encoding * ));
 rb_encoding *pg_conn_enc_get                           _(( PGconn * ));