WINSOCK 非套接字上的套接字操作

Question

这是类方法（所有方法和变量都声明为公共） 注意：DiscoverWinsockLib 负责 WSAStartup 的工作，我知道该部分可以工作。它还执行 LoadLibrary 并查找以下函数的 DLL 入口点，并使用 lpfn_ 前缀重命名。

无论我做什么，我似乎都无法解决为什么我会收到线程中非套接字上的套接字操作的错误条件。

非常感谢任何帮助。

bool __fastcall TRANSPORT::Establish (const char *host, int port, int timeout)
{
bool rFlag;
int rval;

rFlag = false;
DiscoverWinsockLib();

if( WSH )
{
    hostEntry = gethostbyname(host);

    if( !hostEntry )
    {
        LastErrorCode = lpfn_WSAGetLastError();
        lpfn_WSACleanup();
        SetErrorMsg();
    }
    else
    {
        CSocket = lpfn_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

        if (CSocket == INVALID_SOCKET)
        {
            LastErrorCode = lpfn_WSAGetLastError();
            SetErrorMsg();
            lpfn_WSACleanup();
        }
        else
        {

            RxDataBuf.len = RXDATA_BUFSIZE;
            RxDataBuf.buf = RxBuffer;
            RxOverlapped.hEvent = lpfn_WSACreateEvent();

            if(RxOverlapped.hEvent == WSA_INVALID_EVENT)
            {
                LastErrorCode = lpfn_WSAGetLastError();
                SetErrorMsg();
                SocketShutdown();
                //lpfn_closesocket(CSocket);
            }
            else
            {
                if(lpfn_WSAEventSelect(CSocket, RxOverlapped.hEvent, FD_ALL_EVENTS) == SOCKET_ERROR)
                {
                    LastErrorCode = lpfn_WSAGetLastError();
                    SetErrorMsg();
                    lpfn_closesocket(CSocket);
                    lpfn_WSACloseEvent(RxOverlapped.hEvent);
                }
                else
                {
                    hThreadIO = CreateThread(0, 0, ProcessEvents, (void *)this, 0, &ThreadID);

                    // Try to connect to the server
                    serverInfo.sin_family = AF_INET;
                    serverInfo.sin_addr = *((LPIN_ADDR)*hostEntry->h_addr_list);
                    serverInfo.sin_port = htons(port);

                    if( lpfn_connect(CSocket, (LPSOCKADDR)&serverInfo, sizeof(struct sockaddr)) == SOCKET_ERROR  )
                    {
                        LastErrorCode = lpfn_WSAGetLastError();
                        if( LastErrorCode != WSAEWOULDBLOCK )
                        {
                            SetErrorMsg();
                            SocketShutdown();
                        }
                        else
            rFlag = true;
                    }
                    else
                        rFlag = true;
                }
            }
        }
    }
}
return(rFlag);
}

这是上面引用的线程：

DWORD WINAPI ProcessEvents(void *pParam)
{

TRANSPORT *T;
WSANETWORKEVENTS NetEvents;
DWORD EIndex;
DWORD  rc;
bool Failure;


T = (TRANSPORT *)pParam;
Failure = false;

do
{
    EIndex = T->lpfn_WSAWaitForMultipleEvents( 1, &T->RxOverlapped.hEvent, false, 3000, true );

    if( EIndex == WSA_WAIT_FAILED )
    {
        T->LastErrorCode = T->lpfn_WSAGetLastError();
        T->SetErrorMsg();
        Failure = true;
    }

    if( EIndex == WSA_WAIT_TIMEOUT )
    {
        if( T->OnConnectTimeout )
            T->OnConnectTimeout(T);

        Failure = true;
    }

}while( EIndex != WAIT_IO_COMPLETION && !Failure );

if( Failure )
    return(EIndex);

// Get the event(s) that occurred and their associated error array
if(T->lpfn_WSAEnumNetworkEvents(T->CSocket, T->RxOverlapped.hEvent, &NetEvents) == SOCKET_ERROR)
{
    T->LastErrorCode = T->lpfn_WSAGetLastError();
    T->SetErrorMsg();
    return(EIndex);
}

// =================================================================
// Code above fetches the event that woke this thread up
// Code below deals with the events as they are detected
// =================================================================

if( NetEvents.lNetworkEvents & FD_CONNECT  )
{
    if( T->OnConnect )
        T->OnConnect(T);

    T->lpfn_WSAResetEvent(T->RxOverlapped.hEvent);
}
else if( ( NetEvents.lNetworkEvents & FD_READ) )
{
    rc = T->lpfn_WSARecv(T->CSocket, &T->RxDataBuf, 1, &T->RxBytes, &T->Flags, &T->RxOverlapped, NULL);
    EIndex = T->lpfn_WSAGetLastError();

    if( (rc == SOCKET_ERROR) && (EIndex != WSA_IO_PENDING || EIndex != WSAEWOULDBLOCK ) )
    {
        T->LastErrorCode = EIndex;
        T->SetErrorMsg();
    }
    else
    {
        rc = T->lpfn_WSAWaitForMultipleEvents(1, &T->RxOverlapped.hEvent, true, INFINITE, true);

        if(rc == WSA_WAIT_FAILED)
        {
            T->LastErrorCode = T->lpfn_WSAGetLastError();
            T->SetErrorMsg();
        }
        else
        {
            rc = T->lpfn_WSAGetOverlappedResult(T->CSocket, &T->RxOverlapped, &T->RxBytes, false, &T->Flags);
            if(!rc)
            {
                T->LastErrorCode = T->lpfn_WSAGetLastError();
                T->SetErrorMsg();
            }
            else
            {
                if( T->RxBytes > 0 && T->OnReceive )
                    T->OnReceive(T);

                T->lpfn_WSAResetEvent(T->RxOverlapped.hEvent);
            }
        }
    }
}

return(rc);
}

**更新** 我发现调用 EIndex = T->lpfn_WSAWaitForMultipleEvents( 1, &T->RxOverlapped.hEvent, false, 3000, true ); 线程函数内部返回 WSA_WAIT_FAILED

如果我禁用线程函数并检查返回值 lpfn_WSAWaitForMultipleEvents，在线程外部，在 connect 调用之后，我得到了 WSAEWOULDBLOCK 的有效返回值。

考虑到我可能在从线程内部获取地址时遇到问题，我将线程代码更改为如下：

DWORD WINAPI ProcessEvents(void *pParam)
{
 ...

WSAEVENT events[1];

T = (TRANSPORT *)pParam;
Failure = false;


do
{
    events[0] = T->RxOverlapped.hEvent;
    EIndex = T->lpfn_WSAWaitForMultipleEvents( 1, events, false, 3000, true );

            ....

但我仍然无法使 WSAWaitForMultipleEvents 满意！

对此有什么想法/建议吗？

Answer 1

如果 connect() 失败，则您将调用 SocketShutdown()。据推测，它会关闭套接字（您没有显示该代码），但是如果线程正在运行，它会首先终止线程吗？否则，您可能会在线程后面关闭套接字。