CSocket如何配置Timeout的功能!!接收的时候老是阻塞!!请教如何写呢?
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Last reviewed: September 19, 1997
Article ID: Q154649
The information in this article applies to:
The Microsoft Foundation Classes (MFC) included with: Microsoft Visual C++, 32-bit Edition, version 4.2
SYMPTOMS
A call to CSocket Connect, Accept, Send, or Receive hangs if a timer is active. CAUSE
CSocket operations are written using "pseudo-blocking." The WinSock API call is not a true blocking call, but if it doesn't return immediately then CSocket will call PumpMessages. PumpMessages looks for the FD_xxx notification and the CSocket function will not return until the FD_xxx notification arrives. PumpMessages will not detect the socket notification if a timer is active because it looks for WM_TIMER messages first. When a WM_TIMER message arrives, the function doesn't look any further for other messages. The PumpMessages function is looking for WM_TIMER messages because it sets up its own timer to cause the application to retry its socket calls and do periodic idle-time processing while waiting for the socket notification. RESOLUTION
There are two possible resolutions:
Disable all timers while making CSocket calls. Override the PumpMessages function so that it only looks for its own WM_TIMER messages and does not pick up other timer messages. This can be done by borrowing the CSocket::PumpMessages function from SOCKCORE.CPP and changing it as follows:
#if _MFC_VER == 0x0420
#define _AFX_SOCK_THREAD_STATE AFX_MODULE_THREAD_STATE
#define WM_SOCKET_NOTIFY 0x0373
#define WM_SOCKET_DEAD 0x0374 #define _afxSockThreadState AfxGetModuleThreadState() #endif BOOL CMySocket::PumpMessages(UINT uStopFlag)
{
#if _MFC_VER != 0x0420
return CSocket::PumpMessages(uStopFlag);
#else // The same socket better not be blocking in more than one place.
ASSERT(m_pbBlocking == NULL); _AFX_SOCK_THREAD_STATE* pState = _afxSockThreadState; ASSERT(pState->m_hSocketWindow != NULL); BOOL bBlocking = TRUE;
m_pbBlocking = &bBlocking;
CWinThread* pThread = AfxGetThread(); // This is not a timeout in the WinSock sense, but more
// like a WM_KICKIDLE to keep message pumping alive
UINT nTimerID = ::SetTimer(pState->m_hSocketWindow, 0,
m_nTimeOut, NULL); if (nTimerID == 0)
AfxThrowResourceException(); BOOL bPeek = TRUE; while (bBlocking)
{
TRY
{
MSG msg;
if (::PeekMessage(&msg, pState->m_hSocketWindow,
WM_SOCKET_NOTIFY, WM_SOCKET_DEAD, PM_REMOVE))
{
if (msg.message == WM_SOCKET_NOTIFY &&
(SOCKET)msg.wParam == m_hSocket)
{
if (WSAGETSELECTEVENT(msg.lParam) == FD_CLOSE)
{
break;
}
if (WSAGETSELECTEVENT(msg.lParam) == uStopFlag)
{
if (uStopFlag == FD_CONNECT)
m_nConnectError = WSAGETSELECTERROR(msg.lParam);
break;
}
}
if (msg.wParam != 0 || msg.lParam != 0)
CSocket::AuxQueueAdd(msg.message, msg.wParam, msg.lParam); bPeek = TRUE;
}
else if (::PeekMessage(&msg, pState->m_hSocketWindow,
WM_TIMER, WM_TIMER, PM_REMOVE))
{
break;
} if (bPeek && ::PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE))
{
if (OnMessagePending())
{
// allow user-interface updates
pThread->OnIdle(-1);
}
else
{
bPeek = FALSE;
}
}
else
{
// no work to do -- allow CPU to sleep
WaitMessage();
bPeek = TRUE;
}
}
CATCH_ALL(e)
{
TRACE0("Error: caught exception in PumpMessage - continuing.\n");
bPeek = TRUE;
}
END_CATCH_ALL
} ::KillTimer(pState->m_hSocketWindow, nTimerID); if (!bBlocking)
{
WSASetLastError(WSAEINTR);
return FALSE;
}
m_pbBlocking = NULL; ::PostMessage(pState->m_hSocketWindow,WM_SOCKET_NOTIFY,0,0); return TRUE; #endif // _MFC_VER
}
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed with the Visual C++ 4.2b patch. For more information on this patch, please see the following articles in the Microsoft Knowledge Base:
ARTICLE-ID: Q156934
TITLE : PATCH: Visual C++ 4.2b Patch ARTICLE-ID: Q160491
TITLE : Information on Files Modified by VC42b Patch: Part 1 of 4 ARTICLE-ID: Q160496
TITLE : Information on Files Modified by VC42b Patch: Part 2 of 4 ARTICLE-ID: Q160505
TITLE : Information on Files Modified by VC42b Patch: Part 3 of 4 ARTICLE-ID: Q160506
TITLE : Information on Files Modified by VC42b Patch: Part 4 of 4
--------------------------------------------------------------------------------Additional query words: CAsyncSocket CSocket hangs timer
Keywords : MfcSockets vcbuglist420 vcfixlist420 kbnetwork kbprg kbbuglist kbfixlist
Technology : kbMfc
Version : 4.2
Platform : NT WINDOWS
Issue type : kbbug
Solution Type : kbfix
THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.
Last reviewed: September 19, 1997
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.
#include "stdafx.h"class CSock : public CSocket
{
virtual BOOL ConnectHelper(const SOCKADDR* lpSockAddr, int nSockAddrLen);
virtual void OnClose( int nErrorCode );
public:
CSock() { m_Kill = TRUE; }
BOOL m_Kill;
};///// sock.cpp
#include "stdafx.h"
#include "Sock.h"/// CSocket modify - timeout module.
BOOL CSock::ConnectHelper(const SOCKADDR* lpSockAddr, int nSockAddrLen)
{
if (m_pbBlocking != NULL)
{
WSASetLastError(WSAEINPROGRESS);
return FALSE;
} m_nConnectError = -1; if (!CAsyncSocket::ConnectHelper(lpSockAddr, nSockAddrLen))
{
if (GetLastError() == WSAEWOULDBLOCK)
{
// Insert....
CTime curt, st;
CTimeSpan span(0, 0, 0, m_nTimeOut); st = CTime().GetCurrentTime();
//.......
while (PumpMessages(FD_CONNECT))
{
if (m_nConnectError != -1)
{
WSASetLastError(m_nConnectError);
return (m_nConnectError == 0);
}
// Insert....
curt = CTime().GetCurrentTime();
if(curt > (st+span))
return FALSE;
//..............
}
}
return FALSE;
}
m_Kill = FALSE;
return TRUE;
}void CSock::OnClose(int nErrorCode)
{
m_Kill = TRUE;
}
nsent=m_MainDlg->m_sRequstSocket->Send(SubmitBox,264);
if (nsent==SOCKET_ERROR)
{
m_MainDlg->AddString("发送失败!");
}
//到下一句就阻塞!!怎样正常接收呢?
nrecv = pMainDlg->m_sRequstSocket->Receive(req,29);
可以直接用CAsyncSocket, 然后可以实现在select 的消息处理函数里
比如实现了OnReceive, 数据来的时候自然后调用该函数了