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I'm trying to achieve overlapped communication with a device, using a virtual serial port. Basic command-response, where \r\n (CRLF, #013#010) ends both command and response. Multiple commands/responses are chained with ';', no response is given if either the command sets up the device, or the command is invalid.
Ie:
"COMMAND1?\r\n" -> "RESP_TO_1\r\n"
"COMMAND2\r\n" -> no response through serial, but flashes a led on the external device
"COMMAND3;COMMAND4?\r\n" -> "RESP_TO_4\r\n"
"COMMAND5?;COMMAND6?\r\n"-> "RESP_TO_5;RESP_TO_6\r\n"
On W98, using latest VCOM drivers, it works perfect. On XP, WriteFile writes nothing, and GetLastError always returns 997..
997 Overlapped I/O operation is in progress. ERROR_IO_PENDING
I looped the code to check all COM ports, and even the unused IR and VCOM ports are showing up ERROR_IO_PENDING...
I changed timeouts, dcb fields, anything, but 997 keeps haunting me.
So, if anyone using XP, virtual com-ports and OVERLAPPED communication could give me a hand?
I included a piece of sample code. (I left out the part where response is read, since WriteFile never writes anything to respond to anyway)
bool CSerial4::OpenPort(int port)<br />
{<br />
if(port<1) <br />
{<br />
m_sError=_T("Illegal port number");<br />
m_iPort=0;<br />
return false;<br />
}<br />
if(m_hPort!=INVALID_HANDLE_VALUE)<br />
{<br />
return true;<br />
}<br />
else<br />
{<br />
char strPort[15];<br />
sprintf(strPort,"\\\\.\\COM%d",port);<br />
m_hPort = ::CreateFile(strPort,<br />
GENERIC_READ|GENERIC_WRITE,
0,
0,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,
0
);<br />
if(m_hPort==INVALID_HANDLE_VALUE )<br />
{<br />
m_sError.Format("CommError(%d)",GetLastError());<br />
return false;<br />
}<br />
DCB dcb = {0};<br />
dcb.DCBlength = sizeof(DCB);<br />
<br />
if (!::GetCommState (m_hPort,&dcb))<br />
{<br />
m_sError.Format("GetCommState: CommError(%d)",GetLastError());<br />
return false;<br />
}<br />
<br />
dcb.fRtsControl = RTS_CONTROL_ENABLE;<br />
dcb.fDtrControl = DTR_CONTROL_ENABLE;<br />
dcb.BaudRate = CBR_9600;<br />
dcb.ByteSize = 8;<br />
dcb.Parity = NOPARITY;<br />
dcb.StopBits = ONESTOPBIT;
dcb.EvtChar = 10;<br />
dcb.XoffChar = 19;<br />
dcb.XoffLim = 512;<br />
dcb.XonChar = 17;<br />
dcb.XonLim = 2048;<br />
<br />
<br />
if (!::SetCommState (m_hPort,&dcb))<br />
{<br />
m_sError.Format("SetCommState: CommError(%d)", GetLastError());<br />
return false;<br />
}<br />
<br />
COMMTIMEOUTS timeouts;<br />
timeouts.ReadIntervalTimeout = MAXDWORD; <br />
timeouts.ReadTotalTimeoutMultiplier = 0;<br />
timeouts.ReadTotalTimeoutConstant = 0;<br />
timeouts.WriteTotalTimeoutMultiplier= 0;<br />
timeouts.WriteTotalTimeoutConstant = 0;<br />
<br />
if (!SetCommTimeouts(m_hPort, &timeouts))<br />
{<br />
m_sError.Format("SetCommTimeouts: CommError(%d)",GetLastError());<br />
return false;<br />
}<br />
<br />
DWORD flags=0;<br />
flags|=EV_RXFLAG;
if (!::SetCommMask(m_hPort,flags))<br />
{<br />
m_sError.Format("SetCommMask: CommError(%d)",GetLastError());<br />
return false;<br />
}<br />
<br />
return true;
}<br />
}<br />
<br />
<br />
bool CSerial4::Request(CString in, CString &out)<br />
{<br />
DWORD dwSize=in.GetLength();<br />
DWORD dwBytesWritten=0;<br />
DWORD dwRead;<br />
DWORD dwMask;<br />
char *psp=m_data;<br />
psp[0]=0;<br />
<br />
OVERLAPPED ovRead; <br />
memset(&ovRead,0,sizeof(OVERLAPPED));<br />
ovRead.hEvent=::CreateEvent(0,1,0,0); <br />
<br />
OVERLAPPED ovWrite; <br />
memset(&ovWrite,0,sizeof(OVERLAPPED));<br />
<br />
char* pin=new char[dwSize+1];<br />
strcpy(pin,in);<br />
::PurgeComm(m_hPort,PURGE_TXABORT|PURGE_RXABORT|PURGE_TXCLEAR|PURGE_RXCLEAR);<br />
if(!::WriteFile (m_hPort,pin,dwSize,&dwBytesWritten ,&ovWrite))<br />
{<br />
m_sError.Format("Write Failed: CommError(%d)",GetLastError());<br />
::CloseHandle(ovWrite.hEvent);<br />
return false;<br />
}<br />
...<br />
..<br />
.<br />
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1. The foll code is what I will use.
STARTUPINFO si = { sizeof(STARTUPINFO) }; PROCESS_INFORMATION pi;
Q1. If the exe launched is a windows app that needs some stuff done by the user, and then it is exited, will the WaitForSIngleObject will come back only after this launched windows app terminates?
Q2. If the launched process awaits the user, but he decides to press some other button on the main program (not the launched program) will the button respond? Or will the main app be unresponsive until the user has dealt with the launched app and exited it?
Appreciate your help,
ns
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Q1: Yes
Q2: Depends. If your code is called from the application thread (the one with the message loop), then yes it will block your app until the launched app exits.
But if you call it from an other thread then your app will not block.
Magnus
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i used the MAPI functions in my C++ program to access my inbox and read the mails from it..
the program worked fine only when i open the outlook window..
is MAPI designed in such a way that it works only when the inbox is opened..
iff the window is not opened i get the output as error: could not log on..
can i access the inbox without opening it?iff yes?how do i do that?
ranjani
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Look at MAPILogon() closely, specifically the items dealing with a session.
Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?
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The reason for this small test program was that I read on google about a possibility that you could not delete a directory that has a FindFirstChangeNotification watch on it. As it turned out, its no problem at all (at least on WinXP). But I noticed another stranger thing.
When I delete the directory in Explorer, the HANDLE is set to signal state and I get a continuous flow of "Something happened".
But when I delete the directory in Total Commander (new name for Windows Commander) I get error 5 (Access is denied.) from FindNextChangeNotification. And the program ends.
This is not really a question, since the correct implementation should check that the director (or file) you are watching still exists. But what really bothered me were the different results from Explorer and Total Commander. So I wondered if some one else has had this problem or if some one knows why this happens.
Here is the small test program I ran while deleting the directory (its written in Visual Studio 6.0 sp5):
int main( int argc, char* argv[] )
{
HANDLE h = ::FindFirstChangeNotification( "d:\\test\\magnus", FALSE, FILE_NOTIFY_CHANGE_FILE_NAME );
if( h == INVALID_HANDLE_VALUE )
{
std::cout << "Error on FFCN: " << ::GetLastError() << std::endl;
return 0;
}
std::cout << "Entering loop" << std::endl;
for( ;; )
{
DWORD dwWaitState = ::WaitForSingleObject( h, INFINITE );
switch( dwWaitState )
{
case WAIT_OBJECT_0:
std::cout << "Something happened" << std::endl;
break;
case WAIT_ABANDONED:
std::cout << "Error WAIT_ABANDONED" << std::endl;
break;
case WAIT_TIMEOUT:
std::cout << "Error WAIT_TIMEOUT" << std::endl;
break;
default:
std::cout << "Error DEFAULT" << std::endl;
break;
}
if( dwWaitState != WAIT_OBJECT_0 )
break;
if( ::FindNextChangeNotification( h ) == 0 )
{
std::cout << "Error on FNCN: " << ::GetLastError() << std::endl;
break;
}
}
::FindCloseChangeNotification( h );
return 0;
}
Magnus
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hello friends..
I am writing a Wizard application. now i want to change the default focus
i.e if i press enter then the wizard automatically set the Next as default button and as this button gets press the app moves to the next Wizard page.
But in between this i want to change the Default button to Cancel. that means when the user clicks the enter key then instead of the Next the Cancel key should be pressed.
In short i want to change the Default button to Cancel instead of next..
Help
Thanx
TAKE CARE
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One solution is SendMessage().
if (pFromButtom->GetSafeHwnd() && pToButton->GetSafeHwnd())
{
DWORD style = pToButton->GetStyle();
if ((style & BS_DEFPUSHBUTTON) != 1)
{
style = pFromButtom->GetStyle();
// Remove default push button style.
style &= ~BS_DEFPUSHBUTTON;
// Set the new style.
::SendMessage(pFromButtom->GetSafeHwnd(), BM_SETSTYLE, static_cast<wparam>(style), static_cast<lparam>(TRUE));
// Inform the dialog about the new default control ID.
::SendMessage(hWnd, DM_SETDEFID, pToButton->GetDlgCtrlID(), 0);
// Get the style.
style = pToButton->GetStyle();
// Add the default push button style.
style |= BS_DEFPUSHBUTTON;
// Set the new style.
::SendMessage(pToButton->GetSafeHwnd(), BM_SETSTYLE, static_cast<wparam>(style), static_cast<lparam>(TRUE));
}
}
Kuphryn
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Hi kuphryn
Where this code should be written i mean in Initdialog or in PreCreate window ??
Thanx
TAKE CARE
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Put in it stdafx.h. Call it whenever you want to change the default button.
Kuphryn
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I'm not sure, but I think SetDefID(IDCANCEL) would work.
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sorry friend Philnessosity
this doesnt Work !!!!
Thanx
TAKE CARE
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Does anyone have source code that you can give me, or a link to a site, for creating/filtering/manipulating shape files? That is, the file set made up of .shp, .shx, and .dbf files?
It doesn't really look too hard, but I don't want to have to start from scratch.
Thanks,
Dave
"You can say that again." -- Dept. of Redundancy Dept.
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I think ArcObjects will do it - but for a price
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I am printing a graphic on a printer DC. I am using the same drawing library for the screen and for the printer output. If I do the printing I have to scale the DC with SetViewportExt to get a proper output on the paper.
But if I scale the printer DC I get a completly ugly output of the graphic on the printer if the ICM (Image Color Matching) option is set in the printer dialog! If I disable ICM in the dialog or using the SetICMMode(hDC, ICM_OFF) the output is correct.
Has anyone an idea why ICM doesn't work correctly if I scale the printer DC?
Thanks in advance.
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I am writing this application for a pocketpc, but I would assume that the basics of the CScrollView class would not differ to much. Here is what I would like to be able to do:
Is it possible to set the size of the view port smaller than the size of the screen and still have a portion of the screen scroll when text rolls off the screen?
What I need is I have some title printed at the top of a View that need to stay static. When text goes beyond the bottom of the screen I want the vertical scroll bars to appear so the user can scroll up and down to view the data, but still have the title's remain visible. Sort of like a frozen row in Excel.
Currently the only work around that I have found is to repaint the entire screen on each up/down click no the scroll bar. This results in screen flicker and is extremley inefficient. Also, using this method does not allow the user to click and drag the scroll bar to a position as the application attempts to redraw the entire screen with each increment.
Thanks,
-Eric
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Adjust the size of the non-client area of the window (in OnNcCreate()) and paint the title in the non-client area.
Ryan "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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Ryan,
Thanks for the help. I don't see an OnNcCreate() in the ppc framework. I thought it would be part of the CWd class but I don't see it defined. I tried altering the CREATESTRUCT in the PreCreateWindow and setting the cy attribute to 300 since the screen is 240 x 320. This I was hoping would give me 20 pixels to work with at the top of the screen.
When you say adjust the non-client area are these actual members of the CWD class?
Thanks again for the help,
-Eric
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I need to get a Modal-Dialog's handle (HWND) before I enter the blocking DoModal() call.
The thing is the Dialog is only created inside DoModal().
Is there a way to create it in some way and then call DoModal() seperately ?
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I need to call DoModal(), I need a Modal dialog that blocks everything else.
I just need to create it before entering the modal loop.
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ohadp wrote:
I need to get a Modal-Dialog's handle (HWND) before I enter the blocking DoModal() call
Why??
Put your code inside OnInitDialog() or OnCreate() in your dialog.
Ryan "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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if you r planning to intialize any variable then you can just write some function in the dialog class and call these just by creating the Object of the class and calling the function before calling domodal
Thanx
TAKE CARE
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This specific dialog doesn't need to knwo to do special stuff in it's OnInitDialog().
What I did eventually was send it a pointer to :
class CRunner
{
public:
virtual void Run() = 0;
};
but I'm still looking for a better way, as in externaly creating the dialog, accessing it's HWND, then entering the Modal-Loop.
Does someone have an example of creating the dialog Modeless, and then entering some sort of message-pumping loop that would make it modal ?
thanks
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I don't have the exact code, but you can do something like this:
CMyDlg dlg = this;
dlg.Create(dlg.IDD);
HWND hWnd = dlg.m_hWnd
EnableWindow(FALSE);
dlg.CenterWindow();
dlg.ShowWindow(SW_SHOW);
int nResult = dlg.RunModalLoop(MLF_SHOWONIDLE);
dlg.DestroyWindow();
EnableWindow(TRUE);
You can also check out MFC's code for DoModal.
Regards,
Alvaro
Hey! It compiles! Ship it.
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