diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index cd657ca32729b1cb52a3da3ee86da63ff0e585ca..4f9cd3fefa71784cb7d3dcc14b38a8a04e7c657a 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -6,7 +6,7 @@
  * Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.32 1999/08/09 03:13:30 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.33 1999/08/16 02:06:25 tgl Exp $
  *
  * NOTES
  *	  Eventually, the index information should go through here, too.
@@ -15,6 +15,7 @@
 #include "postgres.h"
 
 #include "catalog/pg_operator.h"
+#include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
@@ -453,6 +454,31 @@ get_oprjoin(Oid opno)
 		return (RegProcedure) NULL;
 }
 
+/*				---------- FUNCTION CACHE ----------					 */
+
+/*
+ * get_func_rettype
+ *		Given procedure id, return the function's result type.
+ */
+Oid
+get_func_rettype(Oid funcid)
+{
+	HeapTuple	func_tuple;
+	Oid			funcrettype;
+
+	func_tuple = SearchSysCacheTuple(PROOID,
+									 ObjectIdGetDatum(funcid),
+									 0, 0, 0);
+
+	if (!HeapTupleIsValid(func_tuple))
+		elog(ERROR, "Function OID %u does not exist", funcid);
+
+	funcrettype = (Oid)
+		((Form_pg_proc) GETSTRUCT(func_tuple))->prorettype;
+
+	return funcrettype;
+}
+
 /*				---------- RELATION CACHE ----------					 */
 
 /*
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 4ca8fddda108359a512ef2077c425c70245dee66..3686b13c5f06c6abfba88a679f3cf8b58d11ac0c 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -5,7 +5,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: lsyscache.h,v 1.19 1999/08/09 03:13:28 tgl Exp $
+ * $Id: lsyscache.h,v 1.20 1999/08/16 02:06:23 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,6 +32,7 @@ extern HeapTuple get_operator_tuple(Oid opno);
 extern Oid	get_negator(Oid opid);
 extern RegProcedure get_oprrest(Oid opid);
 extern RegProcedure get_oprjoin(Oid opid);
+extern Oid	get_func_rettype(Oid funcid);
 extern int	get_relnatts(Oid relid);
 extern char *get_rel_name(Oid relid);
 extern struct varlena *get_relstub(Oid relid, int no, bool *islast);