C / C++ / MFC

12-Oct-07 3:29

void CSerialRecieveDlg::OnBtnAutosend()
{
// TODO: Add your control notification handler code here
if(!m_ctrlMSCommCOM1.GetPortOpen())
AfxMessageBox("please open the port!");
else
{
CCreateName Dlg;
CString TB_Name;
CString mstr;
if(Dlg.DoModal()==IDOK)
{
TB_Name=Dlg.m_TableName;
}

m_pRecordset->Close();

//// create a new table in SQL

mstr.Format("IF NOT EXISTS (SELECT * FROM sysobjects WHERE name = '");
mstr+=TB_Name;
mstr+="') CREATE TABLE ";
mstr+=TB_Name;
mstr+=" (ID INT,FangWei TEXT,FuYang TEXT,QingXie TEXT)";

try
{
m_pRecordset->Open(mstr.AllocSysString theApp.m_pConnection.GetInterfacePtr(),
adOpenDynamic,
adLockOptimistic,
adCmdText);

}

catch(_com_error *e)
{
AfxMessageBox(e->ErrorMessage());

}

SetTimer(1,500,NULL);

}
}

when debug to the end, appear an error about "stackoverflow"
what is the problem??

wuhuaiji

David Crow12-Oct-07 3:44

12-Oct-07 3:44

nibabug wrote:
SetTimer(1,500,NULL);

What are you doing in response to the WM_TIMER message?

"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

nibabug12-Oct-07 3:51

12-Oct-07 3:51

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->ErrorMessage());
}

var = m_pRecordset->GetCollect("Value");
if(var.vt != VT_NULL)
str = (LPCSTR)_bstr_t(var);
m_strAGFY=str;
var = m_pRecordset->GetCollect("HexValue");
if(var.vt != VT_NULL)
str = (LPCSTR)_bstr_t(var);
strSendFY=str;
unsigned int intFY=(unsigned int)_tcstoul(strSendFY, 0, 16);
intFY&=0x3fff;
intFY<<=2;
intFY|=0x0001;

SQLNumQX++;
if(SQLNumQX==458)
SQLNumQX-=457;
strSql.Format("%d",SQLNum);
strnum=strSql;

strSql.Format("SELECT * FROM TB_QINGXIE 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());
}

var = m_pRecordset->GetCollect("Value");
if(var.vt != VT_NULL)
str = (LPCSTR)_bstr_t(var);
m_strAGQX=str;
var = m_pRecordset->GetCollect("HexValue");
if(var.vt != VT_NULL)
str = (LPCSTR)_bstr_t(var);
strSendQX=str;

unsigned int intQX=(unsigned int)_tcstoul(strSendQX, 0, 16);
intQX&=0x3fff;
intQX<<=2;
intQX|=0x0002;

strSend="";
// strSend+="$";
str.Format("%4x",intFW);
strSend+=str;
str.Format("%4x",intFY);
strSend+=str;
str.Format("%4x",intQX);
strSend+=str;

// CString m_str;
unsigned int crc;
unsigned char* ptr;
unsigned char len;

str=strSend;
char* pszTest = (char*)(LPCTSTR)str;

ptr=(unsigned char*)pszTest;
len=str.GetLength();

crc=0;
crc=ban_crc(ptr,len);//计算校验值
strSend.Format("$");
strSend+=str;
// str=m_sSendData;
// m_str+=str;
str.Format("*");
strSend+=str;

str.Format("%04x",crc);
strSend+=str;
m_ctrlMSCommCOM1.SetOutput(COleVariant(strSend));//发送数据

UpdateData(FALSE);

// m_AccessList.AddString( strName + " --> "+strAge );

// m_pRecordset->MoveNext();

CDialog::OnTimer(nIDEvent);
}

wuhuaiji

David Crow12-Oct-07 3:56

12-Oct-07 3:56

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

"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

toxcct12-Oct-07 4:36

toxcct

12-Oct-07 4:36

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

David Crow12-Oct-07 4:43

12-Oct-07 4:43

What, pray tell, are you finding amusing?

"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

toxcct12-Oct-07 4:47

toxcct

12-Oct-07 4:47

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

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

nibabug12-Oct-07 4:11

12-Oct-07 4:11

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 Crow12-Oct-07 4:32

12-Oct-07 4:32

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.

"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

Mike Dimmick12-Oct-07 6:10

Mike Dimmick

12-Oct-07 6:10

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.

DoEvents: Generating unexpected recursion since 1991

nibabug12-Oct-07 15:24

12-Oct-07 15:24

thanks a lot Smile | :)

wuhuaiji

Monitor hard drive light via a C++ program in Windows XP

Jonathan [Darka]12-Oct-07 3:44

Jonathan [Darka]

12-Oct-07 3:44

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

Jonathan Wilkes
Darka[Xanya.net]

isikorsky9112-Oct-07 3:22

isikorsky91

12-Oct-07 3:22

Hello!

I am trying to monitor the hard drive LED via a program I am writing in C++ for Windows XP. I just need to know if the light is on/off (the hard drive running). The user will not be able to see the light because of the placement of the computer & we cannot crack open the computer to wire it someplace else because of warranty issues. I need to incorporate it directly into a program I am writing - I cannot use any off the shelf program to show me the LED in the corner of the windows page because my custom display will take up the whole screen.

Any suggestions of how to get to status of the hard drive LED from my c++ program?

Thanks!
Margaret

Re: Monitor hard drive light via a C++ program in Windows XP

David Crow12-Oct-07 3:43