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I am trying to write a C++ program to be used on Win2000 that talks through a RocketPort Serial Hub form Comport. The RocketPort connects to the computer via an ethernet connection and is addressed by virtual COM ports (currently COM3 - COM10). Basically, I will have a rack of devices with each device connected to one of the ports on the back of hub. Since the rack device use will be simple and controlled with function calls and development time is limited, I am using using non-overlapped I/O. From reading through the Platform SDK and Windows API documentation, non-overlapped I/O seems sufficient given how the devices will be used. The program is to write data to the devices in the rack and then receive and parse their response.
The basic structure of each of the program's functions is as follows:
1. Open the port using CreateFile(), and set control settings using
GetCommState() and SetCommState().
2. Write data to the rack device using WriteFile().
3. Receive data from the rack device using ReadFile() and parse the response.
4. Restore previous port settings and close the port.
The problem I am having is in using the Communication Time-outs. When I
don't use them, the program works fine. However, I need to use the
timeouts so that my program can report an error state if there is a
problem with communication (ex. one of the serial cables is unplugged). Without using the timeouts, the current program will
freeze on the ReadFile function if the computer is unable to communicate with the devices.
When I try to set the timeouts, using the COMMTIMEOUTS structure with
GetCommTimeouts() and SetCommTimeouts(), the WriteFile() function returns
as if the data was sent. However, the data isn't actually being sent.
Since the data is not actually being sent, the rack device doesn't respond and the program freezes waiting for the devices' response.
I determined the data is not being sent because (1) the port LED doesn't
flash, (2) the rack device doesn't respond, and (3) when I fill the
COMSTAT structure, using the ClearCommError() function after I called the
WriteFile() function, the cbOutQue member indicates that data is remaining to be transmitted even though the Microsoft Platform SDK explicitly states that this member is zero when non-overlapped operations are used.
Another interesting quirk, if I step through the program in debug mode,
the program actually works with the timeouts, but this is the only way it
will work when using the timeouts.
When I run this same program over the serial port on the back of the
computer (COM1), it works whether or not I use the timeouts. Its only when I try to use one of the ports on the RocketPort (COM3 - COM10), that I have this problem. Also, I've tried this by naming the ports both COM# and \\.\COM# (the naming convention that is suggested may be necessary in Comtrol's documentation) with both naming conventions producing the same results.
/**********************************************************************/
/* This function connects to and configures a COM port */
/**********************************************************************/
BOOL JM::OpenPort()
{
BOOL bSuccess;
dwLastError=ERROR_SUCCESS;
CString m_PortName = "COM3";
hFile = CreateFile(m_PortName,
GENERIC_READ | GENERIC_WRITE,
0, // comm devices must be opened w/exclusive-access
NULL, // no security attributes
OPEN_EXISTING, // comm devices must use OPEN_EXISTING
0, // not overlapped I/O
NULL // hTemplate must be NULL for comm devices
);
if(hFile == INVALID_HANDLE_VALUE)
{
dwLastError = GetLastError();
return false;
}
bSuccess = GetCommTimeouts(hFile, &TimeOuts);
if (!bSuccess)
{
dwLastError = GetLastError();
return false;
}
old_TimeOuts = TimeOuts;
memset(&TimeOuts, 0, sizeof(COMMTIMEOUTS));
TimeOuts.ReadIntervalTimeout = 0;
TimeOuts.ReadTotalTimeoutMultiplier = 0;
TimeOuts.ReadTotalTimeoutConstant = 0;
TimeOuts.WriteTotalTimeoutMultiplier = 0;
TimeOuts.WriteTotalTimeoutConstant = 0;
bSuccess = SetCommTimeouts(hFile, &TimeOuts);
if (!bSuccess)
{
dwLastError = GetLastError();
return false;
}
bSuccess = GetCommState(hFile, &dcb);
if (!bSuccess)
{
dwLastError = GetLastError();
return false;
}
old_dcb = dcb;
dcb.BaudRate = CBR_9600; // set the baud rate
dcb.ByteSize = 8; // data size, xmit, and rcv
dcb.Parity = NOPARITY; // no parity bit
dcb.StopBits = ONESTOPBIT; // one stop bit
dcb.fBinary=true;
dcb.fDtrControl=DTR_CONTROL_ENABLE;
dcb.fRtsControl=RTS_CONTROL_ENABLE;
dcb.fParity=false;
dcb.fOutX=false;
dcb.fInX=false;
dcb.fNull=false;
dcb.fAbortOnError=false;
dcb.fOutxCtsFlow=false;
dcb.fOutxDsrFlow=false;
dcb.fTXContinueOnXoff=false;
dcb.fDsrSensitivity=false;
bSuccess = SetCommState(hFile, &dcb);
if (!bSuccess)
{
dwLastError = GetLastError();
return false;
}
return true;
}
/****************************************************************/
/* This is a boiler-plate query function that is called by each */
/* specific query function. *mstrRX is the CString where the */
/* ASCII response is stored. mstrCommand is the command string */
/* that determines what information is retrieved */
/****************************************************************/
BOOL JM::Query(CString *mstrRX, CString mstrCommand)
{
BOOL bWrite_chk, bRead_chk, bSuccess, bPort_chk;
CString TX_str, Rx_temp_str;
DWORD dwBytes_Written, dwBytes_Read;
char *pcRead_Buff = new char;
int i;
bPort_chk = OpenPort(); //Connect to port and configure
if(!bPort_chk)
return false;
TX_str += mstrCommand;
bWrite_chk = WriteFile(hFile,TX_str,TX_str.GetLength(),
&dwBytes_Written,NULL);
if(!bWrite_chk)
{
dwLastError = GetLastError();
return false;
}
bPort_chk = ClearCommError(hFile,&dwCommError,&PortStatus);
if(!bPort_chk)
return false;
i=0;
bRead_chk = ReadFile(hFile,pcRead_Buff,1,&dwBytes_Read,NULL);
if(bRead_chk)
{
while ((pcRead_Buff[i] != '\r'))
{
bRead_chk = ReadFile(hFile,pcRead_Buff,1,&dwBytes_Read,NULL);
Rx_temp_str += *pcRead_Buff;
}
*mstrRX = Rx_temp_str;
}
else
{
dwLastError = GetLastError();
return false;
}
bSuccess = ClosePort();
if(!bSuccess)
return false;
delete pcRead_Buff;
return true;
}
Thanks in advance for any help that can be offered.
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This is how I normally configure the timeouts for a COM port:
COMMTIMEOUTS timeouts;
timeouts.ReadIntervalTimeout = MAXDWORD;
timeouts.ReadTotalTimeoutConstant = 0;
timeouts.ReadTotalTimeoutMultiplier = 0;
timeouts.WriteTotalTimeoutConstant = 0;
timeouts.WriteTotalTimeoutMultiplier = 0;
SetCommTimeouts(m_hSerialPortHandle, &timeouts);
This means that the WriteFile() call doe snot return until the characters have been sent, but for ReadFile() this becomes a polling operation. I normally loop around a thread that tries to read a character every x ms and sleeps in between. This has always worked well for me. You just need to check the value of dwNumBytesRead in the ReadFile() call.
Hope its of help.
Roger Allen
Sonork 100.10016
Were you different as a kid? Did you ever say "Ooohhh, shiny red" even once? - Paul Watson 11-February-2003
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I have a FormView based mfc program. I am trying to adjust my program so it can adapt to different screen resolution.
I have the following code in my OnDraw function, but it fails to adapt window size on different screen resolution.
CRect rc;
SystemParametersInfo(SPI_GETWORKAREA,0,rc,0);
I don't know what I'm missing, or if there is anything wrong with my code.
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I would do it like this:
RECT rc;
SystemParametersInfo(SPI_GETWORKAREA, 0, &rc, 0);
-Dominik
_outp(0x64, 0xAD);
and
__asm mov al, 0xAD __asm out 0x64, al
do the same... but what do they do?? 
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I tried this, but it still will not adapt to different screen resolution. Is it okay to have GetSystemMetrics in MainFrame?
void CMainFrame::OnMove(int x, int y)
{
Rect rc;
SystemParametersInfo(SPI_GETWORKAREA,0,&rc,0);
}
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Does anyone know how to disable a checkbox without disabling its text? I want the box disabled but the text to be normal. Basically so it looks like a regular checkbox you have no control over.
-dork
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I would just introduce an internal flag which indicates if the checkbox is disabled or not. Then implement a callback function which gets called when the state of the checkbox changes. UpdateData(TRUE). If the checkbox flag indicates disabled, invert the current state, else not.
-Dominik
_outp(0x64, 0xAD);
and
__asm mov al, 0xAD __asm out 0x64, al
do the same... but what do they do??
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Dominik Reichl wrote:
If the checkbox flag indicates disabled, invert the current state, else not.
this would enable the checkbox if it is disabled. this is not what he wants. he wants that check box is disabled but its text appears as enabled i.e checkbox is no longer able to respond to user but its text appears as enabled.
Muhammad Shoaib Khan
http://geocities.com/lansolution
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M.Shoaib Khan wrote:
this would enable the checkbox if it is disabled.
Nope. You make a call to the UpdateData(TRUE) function. Therefor the member variable for the checkbox contains the _new_ state of the checkbox. If you want to ignore the change, you therefor have to invert the state now.
-Dominik
_outp(0x64, 0xAD);
and
__asm mov al, 0xAD __asm out 0x64, al
do the same... but what do they do??
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You can derive class from CButton. In your derived class, provide a function in which u create a static control and places it just over the text area of your check box. Use GetWindowText or any other function to get combo box text.
Provide your own function for enabling and disabling in which after calling base class implementation, redraw static control. i hope that works.
Muhammad Shoaib Khan
http://geocities.com/lansolution
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I need a HBITMAP to add a bitmap to a toolbar and menu. I can get an HICON from the .exe's that contain the images, but I'm not sure if there is a simple way to get an HBITMAP from the HICON without going through the whole bitblt process.
Any idea if there is a fairly simple way to do this?
Thank you,
Dave
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I am not sure, but perhaps you should have a look at the GetIconInfo Windows API function. This function gives you an ICONINFO struct which contains HBITMAP handles to the color and the mask bitmap.
If you use GetIconInfo you have to delete the handles to the two newly created bitmaps yourself. Read MSDN for more.
-Dominik
_outp(0x64, 0xAD);
and
__asm mov al, 0xAD __asm out 0x64, al
do the same... but what do they do??
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Hi everybody
I'm developing an application for my final thesis. I need to use a Real Time transport protocol to carry some data from a PC to a PDA (Pocket PC). I thought maybe WinRTP could work in the PDA side, but I don't find the "CE version". Actually, i don't even know if it does exist. If it does, where can I find it? and maybe some examples...if it doesn't, any idea what other real time protocol could i use?
Thank you all in advance,
Javi
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Greetings
I am writing an app to import data from an Access DB. I am fetching the information about columns of a table by using the following method -
SQLCHAR colname[SIZE_128+1]={0};
SQLINTEGER colsize=0;
SQLSMALLINT decimaldigit=0;
// allocate.
VERIFY ( (retcode = SQLAllocHandle ( SQL_HANDLE_STMT, sqlhdbc, &hstmt )) == SQL_SUCCESS );
retcode = SQLColumns ( hstmt, NULL, 0, NULL, 0, (SQLCHAR*)szTable, SQL_NTS, NULL, 0 );
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
/* Bind columns in result set to buffers */
SQLBindCol(hstmt, 4, SQL_C_CHAR, colname, SIZE_128, &size );
SQLBindCol(hstmt, 7, SQL_C_SLONG, &colsize, 0, &size );
SQLBindCol(hstmt, 9, SQL_C_SSHORT, &decimaldigit, 0, &decsize );
}
while( TRUE )
{
retcode = SQLFetch(hstmt);
if ( retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO ) {
// do stuff
} else {
break;
}
}
Now the problem is that even if a column is defined as DOUBLE in Access and has data like 2.345, 3.001, 0.0001 etc.
The decimaldigit is always returned with value 0. Therefore I am not able to get the correct decimal point for the column.
So instead of getting colsize = 15 and decimaldigit = 2, I am always getting colsize = 15 and decimaldigit = 0?
Am I doing something wrong?
Thanks in advance.
Karam
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Perhaps you should have something like:
SQL_C_DOUBLE decimaldigit;<br />
SQLBindCol(hstmt, 9, SQL_C_DOUBLE, &decimaldigit, 0, &decsize);
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SQL_C_DOUBLE is defined as 8. So I used
SQLDOUBLE decimaldigit;
SQLBindCOl ( hstmt, 9, SQL_C_DOUBLE, &decimaldigit, 0, &decsize );
For the double column the decimaldigit value is 0.000000000 and decsize it is -1.
I am confused. Even the MSDN docs tell me to use the function this way 
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I have never been a fan of SQLColumns.... usually I just do a 'select * from <tablename> where 1=0' and use the following fcns to get metadata (sorry for the code bloat...):
short DBStatement::GetColDBType(int iColumnNum)
{
short iStatus;
char caDummy[2];
short iDummy;
long lColType = -1;
if (m_hStmtHdl)
{
ResetError();
iStatus = ::SQLColAttributes(m_hStmtHdl,(UWORD)iColumnNum,(UWORD)SQL_COLUMN_TYPE,(PTR)caDummy,(SWORD)1,(SWORD *)&iDummy,(SDWORD *)&lColType);
if (iStatus != SQL_SUCCESS && iStatus != SQL_SUCCESS_WITH_INFO)
{
UpdateDBError();
lColType = -1;
}
}
else
NoActiveStatement();
return (short)lColType;
}
LPSTR DBStatement::GetColName(int iColumnNum)
{
short iStatus;
long lDummy;
short iDummy;
InitDataBuffer();
if (m_hStmtHdl)
{
ResetError();
iStatus = ::SQLColAttributes(m_hStmtHdl,(UWORD)iColumnNum,(UWORD)SQL_COLUMN_NAME,(PTR)m_caDataBuf,(SWORD)1000,(SWORD *)&iDummy,(SDWORD *)&lDummy);
if (iStatus != SQL_SUCCESS && iStatus != SQL_SUCCESS_WITH_INFO)
{
UpdateDBError();
m_caDataBuf[0] = 0;
}
}
else
NoActiveStatement();
return m_caDataBuf;
}
long DBStatement::GetColWidth(int iColumnNum)
{
short iStatus;
char caDummy[2];
long lColWidth = -1;
short iDummy;
if (m_hStmtHdl)
{
ResetError();
iStatus = ::SQLColAttributes(m_hStmtHdl,(UWORD)iColumnNum,(UWORD)SQL_COLUMN_LENGTH,(PTR)caDummy,(SWORD)1,(SWORD *)&iDummy,(SDWORD *)&lColWidth);
if (iStatus != SQL_SUCCESS && iStatus != SQL_SUCCESS_WITH_INFO)
UpdateDBError();
}
else
NoActiveStatement();
return lColWidth;
}
int DBStatement::GetNumCols()
{
short iStatus;
short iRetval = -1;
if (m_hStmtHdl)
{
ResetError();
iStatus = ::SQLNumResultCols(m_hStmtHdl,(short *)&iRetval);
if (iStatus != SQL_SUCCESS && iStatus != SQL_SUCCESS_WITH_INFO)
UpdateDBError();
}
else
NoActiveStatement();
return (int)iRetval;
}
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The point being that you can develop a generic function to return your metadata using the SQLColAttributes ODBC call.
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Hi guys
Somebody knows how to add the tooltip feature to the CLabel class that is here in Codeproject (SledgeHammer did this class). I've tried a solution but it doesn't work.
Best Regards
Dr.Pi
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Hi guys
I've got an SDI app and from the View window I call a Modal Dialog.
When this dialog opens, the underneath view is not refreshed (all text is unreadable).
What I have to do to repaint the view meantime I am in the modal dialog?
Best Regards
Dr.Pi
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One solution is Invalidate().
Kuphryn
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I've got the same thing with one of my SDI apps, but it works fine. What styles are you using to create the dialog with?
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Hi David
My styles are
Style : Child
Border : None
Nothing more checked in this dialog.
Hi Kuphryn
Where I have to put the Invalidate() meantime I am in the modal dialog?
Bsst Regards
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Just for grins, change the style to Popup and see what happens.
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Hi guys
I've discovered part of the problem.
I'm using CLabel class and when is repainted when the modal dialog is open the values are centered instead that left aligned amd made me thing that I had a repaint problem.
I don't know where could be the problem. I'll try to find.
Thanks
Dr.Pi
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