void SendStr(int connfd, std::string str)
{
    uint16_t *len = new uint16_t(str.size());
    const char * lenByte = (char *)len;
    char *sendByte = new char[*len + 2]{0};
    memcpy(sendByte,lenByte,sizeof(*len));
    memcpy(sendByte + 2, str.c_str(), *len);
    std::cout << "str size " << *len << std::endl;
    //std::cout << "len size " << sizeof(len) << std::endl;

    size_t nleft = *len + 2;
    std::cout << "need to send " << nleft << std::endl;
    int nsend = 0;
    while (nleft > 0)
    {
        //std::cout << "sending " << nleft << "bytes" << std::endl;
        if (nsend = (write(connfd, sendByte + nsend, nleft)) < 0)
        {
            if (errno == EINTR)
                continue;
            ERROR_EXIT("send");
        }
        else if (nsend == 0)
            //continue;
            break;
        nleft -= nsend;
        std::cout << "sended " << nsend << " left " << nleft << std::endl;
    }
    std::cout << "send complete" << std::endl;
    delete[] sendByte;
    delete len;
}

这里是完整的代码
我看到write和send函数返回字节数的和，而这里返回0，并且客户端似乎运行正常，这让我很困惑。