Function findRangeCanonicalFunction

src/backend/commands/typecmds.c:2458–2497

}

static Oid
findRangeCanonicalFunction(List *procname, Oid typeOid)
{
	Oid			argList[1];
	Oid			procOid;
	AclResult	aclresult;

	/*
	 * Range canonical functions must take and return the range type, and must
	 * be immutable.
	 */
	argList[0] = typeOid;

	procOid = LookupFuncName(procname, 1, argList, true);

	if (!OidIsValid(procOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("function %s does not exist",
						func_signature_string(procname, 1, NIL, argList))));

	if (get_func_rettype(procOid) != typeOid)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("range canonical function %s must return range type",
						func_signature_string(procname, 1, NIL, argList))));

	if (func_volatile(procOid) != PROVOLATILE_IMMUTABLE)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("range canonical function %s must be immutable",
						func_signature_string(procname, 1, NIL, argList))));

	/* Also, range type's creator must have permission to call function */
	aclresult = pg_proc_aclcheck(procOid, GetUserId(), ACL_EXECUTE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(procOid));

	return procOid;
}

static Oid
findRangeSubtypeDiffFunction(List *procname, Oid subtype)