openssl windows 本地配置问题

$config = array(
'config'=>'D:\wamp\bin\apache\apache2.2.22\conf\openssl.cnf',//本地测试用
'digest_alg' => $code,
'private_key_bits' => 2048,
'private_key_type' => OPENSSL_KEYTYPE_RSA,
);

//创建公钥密钥中间变量
$tmp = openssl_pkey_new($config);

//如果中间变量生成成功
if ($tmp) {
//根据中间变量生成私钥
//            openssl_pkey_export($tmp, $privateKey);
openssl_pkey_export($tmp, $privateKey, null, $config);//本地测试用
//            var_dump($privateKey);exit;
//根据中间变量生成公钥
$publicKey = openssl_pkey_get_details($tmp);
$publicKey = $publicKey['key'];

} else {
Yii::app()->end();
}

原因在于配置里没指定openssl配置文件路径  ：'config'=>'D:\wamp\bin\apache\apache2.2.22\conf\openssl.cnf',//本地测