- var_dump: documentation ( source)
- microtime: documentation ( source)
- date: documentation ( source)
- preg_replace: documentation ( source)
- str_pad: documentation ( source)
<?php
$sMicrotime = microtime(true);
$sMsgId = preg_replace('/^.+\./', '', $sMicrotime);
$sDatetime = date('YmdHis').str_pad(preg_replace('/^.+\./', '', $sMicrotime), 4, '0', STR_PAD_LEFT);
echo '<pre>';
var_dump($sMicrotime);
var_dump($sMsgId);
var_dump($sDatetime);
echo '</pre>';