Function get_typsubscript

src/backend/utils/cache/lsyscache.c:3697–3719

* get_typsubscript * * Given the type OID, return the type's subscripting handler's OID, * if it has one. * * If typelemp isn't NULL, we also store the type's typelem value there. * This saves some callers an extra catalog lookup. */

 * This saves some callers an extra catalog lookup.
 */
RegProcedure
get_typsubscript(Oid typid, Oid *typelemp)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typform = (Form_pg_type) GETSTRUCT(tp);
		RegProcedure handler = typform->typsubscript;

		if (typelemp)
			*typelemp = typform->typelem;
		ReleaseSysCache(tp);
		return handler;
	}
	else
	{
		if (typelemp)
			*typelemp = InvalidOid;
		return InvalidOid;
	}
}

/*
 * getSubscriptingRoutines