PHP: Fatal error:Call to undefined function com_create_guid()

本地Windows环境执行正常，放在Linux服务器上出现致命错误：
Fatal error:Call to undefined function com_create_guid()

原因是服务器PHP版本较高(5.4)，没有内置支持com_create_guid()函数，
参见PHP官方网站安装说明（ http://php.net/manual/en/com.installation.php）：

"From PHP 5.4.5, COM and DOTNET is no longer built into the php core. You have to add COM support in php.ini"

所以要么在php.ini中添加com扩展，要么修改下获取GUID函数的实现以兼容各个PHP版本，如下所示：

function getGUID(){
    if (function_exists('com_create_guid')){
        return com_create_guid();
    }else{
        mt_srand((double)microtime()*10000);//optional for php 4.2.0 and up.
        $charid = strtoupper(md5(uniqid(rand(), true)));
        $hyphen = chr(45);// "-"
        $uuid = chr(123)// "{"
            .substr($charid, 0, 8).$hyphen
            .substr($charid, 8, 4).$hyphen
            .substr($charid,12, 4).$hyphen
            .substr($charid,16, 4).$hyphen
            .substr($charid,20,12)
            .chr(125);// "}"
        return $uuid;
    }
}

参考链接：
http://php.net/manual/en/function.com-create-guid.php

by iefreer