你不能打包整个对象，成员。所以，像

You can't pack() a whole object, but you can pack() and concatenate the members. So, something like

$packed = pack('I', $pMsgBlock->nSize)
.pack('I', $pMsgBlock->nSanity1)
.pack('I', $pMsgBlock->nSanity2)
.pack('I', $pMsgBlock->nChecksum)
.mb_convert_encoding($pMsgBlock->szText, 'UTF-16');