WSARecvFrom的奇怪问题

[zhyaaa123]

下面这个接收过程，当我接收一个大小为MAX_PACKET_SIZE的包时，接收一次，再接收就失败了，但是如果我把MAX_PACKET_SIZE加1或减1就能够连续接收（减有些数字还是不能，MAX_PACKET_SIZE=1024），是什么原因？

DWORD WINAPI CP2PClient::RecvThreadProc(LPVOID lpParam)
{
CP2PClient *pThis = (CP2PClient *)lpParam;
char buff[MAX_PACKET_SIZE];
sockaddr_in remoteAddr;
int nAddrLen = sizeof(remoteAddr);
WSABUF wsaBuf;
wsaBuf.buf = buff;
wsaBuf.len = MAX_PACKET_SIZE;

while(TRUE)
{
DWORD dwRecv, dwFlags = 0;
int nRet = ::WSARecvFrom(pThis->m_s, &wsaBuf,
1, &dwRecv, &dwFlags, (sockaddr*)&remoteAddr, &nAddrLen, &pThis->m_ol, NULL);
if(nRet == SOCKET_ERROR && ::WSAGetLastError() == WSA_IO_PENDING)
{
::WSAGetOverlappedResult(pThis->m_s, &pThis->m_ol, &dwRecv, TRUE, &dwFlags);
}

if(pThis->m_bThreadExit)
break;
pThis->HandleIO(buff, dwRecv, (sockaddr *)&remoteAddr, nAddrLen);
}
return 0;
}

[toxyboy]

..有这有接收的吗？接收事件因该是你完成事件通知的时候在接收，这个好循环接收的吗？

[zhyaaa123]

发现如果MAX_PACKET_SIZE是8的倍数的时候就会失败，如果不是就没有问题