Re: Using CWinThread in MFC apps

From:
Stephen Myers <""StephenMyers\"@discussions@microsoft.com">
Newsgroups:
microsoft.public.vc.mfc
Date:
Mon, 03 Aug 2009 12:25:07 -0500
Message-ID:
<#Z5vZ9FFKHA.3708@TK2MSFTNGP02.phx.gbl>
Jack wrote:

Thanks guys for the help..
I ran into another problem now.
My CSocket::OnReceive is never called.
I searched the net and some website suggested
that I was stucked in a loop instead of the message pump
I looked here and there for a couple of hours but still
couldn't find the bug...
Could you please help?

[code]
// Socket.cpp : implementation file

//

#include "stdafx.h"

#include "CDemo.h"

#include "Socket.h"

#include ".\socket.h"

class CCDemoDoc;

UINT __cdecl Sock_Handler(LPVOID arg);

SOCKET hConnected;

// cSocket

cSocket::cSocket()

{

OutputDebugString("cSocket::cSocket\n");

}

cSocket::cSocket(CCDemoDoc *pDoc)

{

m_Doc = pDoc;

}

cSocket::~cSocket()

{

OutputDebugString("cSocket::~cSocket\n");

}

// cSocket member functions

void cSocket::OnAccept(int nErrorCode)

{

OutputDebugString("cSocket::OnAccept\n");

//Accept(this);

Attach(hConnected);

// TODO: Add your specialized code here and/or call the base class

AfxBeginThread(Sock_Handler, this);

CSocket::OnAccept(nErrorCode);

}

void cSocket::OnClose(int nErrorCode)

{

OutputDebugString("cSocket::OnClose\n");

// TODO: Add your specialized code here and/or call the base class

CSocket::OnClose(nErrorCode);

}

void cSocket::OnConnect(int nErrorCode)

{

OutputDebugString("cSocket::OnConnect\n");

// TODO: Add your specialized code here and/or call the base class

CSocket::OnConnect(nErrorCode);

}

void cSocket::OnOutOfBandData(int nErrorCode)

{

OutputDebugString("cSocket::OnOutOfBandData\n");

// TODO: Add your specialized code here and/or call the base class

CSocket::OnOutOfBandData(nErrorCode);

}

void cSocket::OnReceive(int nErrorCode)

{

OutputDebugString("cSocket::OnReceive\n");

char buff[4096];

int nRead;

nRead = Receive(buff, 4096);

if (nRead != SOCKET_ERROR)

{

if (nRead)

{

buff[nRead] = 0;

CString szTemp(buff);

// ((CMsocsDlg*)m_pDlg)->m_strRecv += szTemp;

// ((CMsocsDlg*)m_pDlg)->UpdateData(FALSE);

// if (szTemp.CompareNoCase("bye") == 0 ) ShutDown();

}

else Close();

}

else

{

wsprintf (buff, "Error number is %d", GetLastError());

AfxMessageBox (buff);

}

CSocket::OnReceive(nErrorCode);

// TODO: Add your specialized code here and/or call the base class

}

void cSocket::OnSend(int nErrorCode)

{

OutputDebugString("cSocket::OnSend\n");

// TODO: Add your specialized code here and/or call the base class

CSocket::OnSend(nErrorCode);

}

int cSocket::Receive(void* lpBuf, int nBufLen, int nFlags)

{

OutputDebugString("cSocket::Receive\n");

// TODO: Add your specialized code here and/or call the base class

return CSocket::Receive(lpBuf, nBufLen, nFlags);

}

int cSocket::Send(const void* lpBuf, int nBufLen, int nFlags)

{

OutputDebugString("cSocket::Send\n");

// TODO: Add your specialized code here and/or call the base class

return CSocket::Send(lpBuf, nBufLen, nFlags);

}

BOOL cSocket::OnMessagePending()

{

OutputDebugString("cSocket::OnMessagePending\n");

// TODO: Add your specialized code here and/or call the base class

return CSocket::OnMessagePending();

}

//////////////////////////////////////

UINT __cdecl Sock_Handler(LPVOID arg)

{

cSocket *pSock = (cSocket*) arg;

while(true)

{

if (!pSock->buff.empty())

{

// pSock->CopyDataToPacket();

pSock->buff.clear();

}

Sleep(500);

}

return 0;

}

[/code]


You've created a worker thread. A worker thread does not have a message
pump so the socket can't notify the thread that there's data available
(OnReceive).

Instead you should derive a class based on CWinThread and use the other
constructor
pThread = static_cast<MyThread>(AfxBeginThread(RUNTIME_CLASS(MyThread));

Joe has some excellent articles on his site.

Steve

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