a problem about stackoverflow

[Jonathan Darka]

Try single stepping through your code in the debugger, it should be obvious then.

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Jonathan Wilkes Darka[Xanya.net]

[nibabug]

get data from three different tables , and then do something , and then show them, look the flowing: void CSerialRecieveDlg::OnTimer(UINT nIDEvent) { // TODO: Add your message handler code here and/or call default CString strSql; // int m=atoi(m_strNum); _variant_t var; CString str,strnum; CString strSendFW,strSendFY,strSendQX; CString strSend; str=""; SQLNum++; if(SQLNum==130) SQLNum-=129; strSql.Format("%d",SQLNum); strnum=strSql; strSql.Format("SELECT * FROM TB_FANGWEI WHERE ID = '%s'",strnum); try { //先关闭已经打开的记录集对象 m_pRecordset->Close(); //根据新的Sql查询语句，重新打开记录集对象 m_pRecordset->Open(strSql.AllocSysString(), theApp.m_pConnection.GetInterfacePtr(), adOpenDynamic, adLockOptimistic, adCmdText); } catch(_com_error *e) { AfxMessageBox(e->ErrorMessage()); } //在ADO操作中建议语句中要常用try...catch()来捕获错误信息， //因为它有时会经常出现一些想不到的错误。 var = m_pRecordset->GetCollect("Value"); if(var.vt != VT_NULL) str = (LPCSTR)_bstr_t(var); m_strAGFW=str; var = m_pRecordset->GetCollect("HexValue"); if(var.vt != VT_NULL) str = (LPCSTR)_bstr_t(var); strSendFW=str; // char* pszTest = (char*)(LPCTSTR)strSendFW; // unsigned char* ptr=(unsigned char*)pszTest; // unsigned char uchartemp; // unsigned char m=4; unsigned int intFW=(unsigned int)_tcstoul(strSendFW, 0, 16); intFW&=0x3fff; intFW<<=2; intFW|=0x0000; strSql.Format("SELECT * FROM TB_FUYANG WHERE ID = '%s'",strnum); try { //先关闭已经打开的记录集对象 m_pRecordset->Close(); //根据新的Sql查询语句，重新打开记录集对象 m_pRecordset->Open(strSql.AllocSysString(), theApp.m_pConnection.GetInterfacePtr(), adOpenDynamic, adLockOptimistic, adCmdText); } catch(_com_error *e) { AfxMessageBox(e->Err

[David Crow]

You are doing WAY too much in response to a WM_TIMER message that occurs every 1/2 second.

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"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[nibabug]

it has no businiss with the timer, because when i change it to 2second, it also appear error： （step debug) unhandled exception in SerialRecieve.exe(KERNEL32.DLL):0xE06D7363:Microsoft C++ EXCEPTION no matter where the error appears, it appears always in the CSerialRecieveDlg::OnTimer(UINT nIDEvent)

wuhuaiji

[David Crow]

nibabug wrote:

it has no businiss with the timer...it appears always in the CSerialRecieveDlg::OnTimer(UINT nIDEvent)

Do you see the irony in this statement? Yes, the timer is the problem. Changing the frequency to 2 seconds won't necessarily solve the problem if it takes longer than that to process a single WM_TIMER request. Put a flag in the function indicating whether it is busy or not. Check that flag before continuing.

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"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[toxcct]

:laugh::laugh::laugh:

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[VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

[David Crow]

What, pray tell, are you finding amusing?

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"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[toxcct]

it was just obvious, but i loved the way you said it

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[VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

[Mike Dimmick]

It's not just the timer - a thread hosting Windows UI can only process one message at a time, after all. The problem is that the MessageBox call and the modal dialog create nested message loops, which will process timer messages and thereby cause recursion. Most likely it's one of the AfxMessageBox calls in the exception handlers in the OnTimer routine which is causing OnTimer to go re-entrant.

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DoEvents: Generating unexpected recursion since 1991

[nibabug]

thanks a lot:)

wuhuaiji