C++面试5_ TCP 粘包2（工业级）

//接收端
#pragma pack(1)
struct protocol_head_
{
    int MainMsgID; // 主消息ID
    int SubMsgID; // 子消息ID
    int DataLen; // 数据长度,不包含头
    int Reserve1; // 预留字段1
};

void Test::recvData()
{
    LOG_DEBUGGING("启动接收数据线程");
    int headLen = sizeof(protocol_head_);
    char *pHeadData = new char[headLen];
    char *pData = nullptr;
    int npDataLen = 0;
    while (m_bInited)
    {
        if (!m_bConnected)
        {
            Sleep(1);
            continue;
        }
        int nRecvLen = 0;
        memset(pHeadData, 0, headLen);

        // 读取头数据，先收固定长度包头
        while (1)
        {

            int len = ::recv(m_s, pHeadData + nRecvLen, headLen - nRecvLen, 0);

            if (len <= 0)
            {// 连接异常
                m_bConnected = false;
                break;