read from comport problem - C / C++ / MFC Discussion Boards

Alexander ^M.,28-Jul-05 8:57

28-Jul-05 8:57

You can't create an easy timeout loop that way. What kind of code is running in the loop? There are normally better ways.

Don't try it, just do it! Wink | ;-)

Re: timeout for while loop

trigger9128-Jul-05 9:33

trigger91

28-Jul-05 9:33

Actually inside the while loop I am reading or writing to a usb device using our library apis...what are the other ways doing it better.

Re: timeout for while loop

Alexander ^M.,29-Jul-05 4:26

Alexander ^M.,

29-Jul-05 4:26

Use completion routines and kinda timeout thread, that makes it easier.

Don't try it, just do it! Wink | ;-)

Re: timeout for while loop

Peter Weyzen28-Jul-05 9:46

Peter Weyzen

28-Jul-05 9:46

HANDLE hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );<br />
<br />
while ( looping )<br />
{<br />
    if( WaitForSingleObject( hEvent, 300 ) == WAIT_TIMEOUT )<br />
    {<br />
        // timeout expired<br />
    }<br />
    else<br />
    {<br />
        // someone called SetEvent on my hEvent (likely)<br />
        // use SetEvent for cause the wait to expire<br />
    }<br />
}

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
<A HREF="http://www.santacruznetworks.com">Santa Cruz Networks</A>

Re: timeout for while loop

Alexander ^M.,29-Jul-05 4:25

Alexander ^M.,

29-Jul-05 4:25

That does not work because when there are more than 1 loop the timeout will be 300ms FOR EVERY LOOP, and not for the whole loop.

Don't try it, just do it! Wink | ;-)

Re: timeout for while loop

David Crow29-Jul-05 6:03

David Crow

29-Jul-05 6:03

Where was it mentioned that multiple loops were involved?

"One must learn from the bite of the fire to leave it alone." - Native American Proverb

Re: timeout for while loop

nm_11429-Jul-05 14:16

nm_114

29-Jul-05 14:16

I don't know if this is a good way to do it but you could try something like:

DWORD t = GetTickCount();
while (1)
{
if ((GetTickCount() - t) > 300)
	break;
}

read from comport problem

quarry_0628-Jul-05 8:42

quarry_06

28-Jul-05 8:42

Hi I am using the library I found here:
http://www.codeproject.com/system/serial.asp
in my program. However, I run into the following problem when I am reading from a comport. (example listener).

I took the code, and created a little function

int readme(CSerial &serial)<br />
{<br />
	LONG    lLastError = ERROR_SUCCESS;<br />
	lLastError = serial.SetMask(CSerial::EEventBreak |<br />
								CSerial::EEventCTS   |<br />
								CSerial::EEventDSR   |<br />
								CSerial::EEventError |<br />
								CSerial::EEventRing  |<br />
								CSerial::EEventRLSD  |<br />
								CSerial::EEventRecv);<br />
	if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Unable to set COM-port event mask"));<br />
<br />
	// Use 'non-blocking' reads, because we don't know how many bytes<br />
	// will be received. This is normally the most convenient mode<br />
	// (and also the default mode for reading data).<br />
    lLastError = serial.SetupReadTimeouts(CSerial::EReadTimeoutNonblocking);<br />
	if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Unable to set COM-port read timeout."));<br />
	<br />
	bool fContinue = true;<br />
	do<br />
	{<br />
		// Wait for an event<br />
		lLastError = serial.WaitEvent();<br />
		if (lLastError != ERROR_SUCCESS)<br />
			return ::ShowError(serial.GetLastError(), _T("Unable to wait for a COM-port event."));<br />
<br />
		// Save event<br />
		const CSerial::EEvent eEvent = serial.GetEventType();<br />
<br />
		// Handle break event<br />
		if (eEvent & CSerial::EEventBreak)<br />
		{<br />
			printf("\n### BREAK received ###\n");<br />
		}<br />
<br />
		// Handle CTS event<br />
		if (eEvent & CSerial::EEventCTS)<br />
		{<br />
			printf("\n### Clear to send %s ###\n", serial.GetCTS()?"on":"off");<br />
		}<br />
<br />
		// Handle DSR event<br />
		if (eEvent & CSerial::EEventDSR)<br />
		{<br />
			printf("\n### Data set ready %s ###\n", serial.GetDSR()?"on":"off");<br />
		}<br />
<br />
		// Handle error event<br />
		if (eEvent & CSerial::EEventError)<br />
		{<br />
			printf("\n### ERROR: ");<br />
			switch (serial.GetError())<br />
			{<br />
			case CSerial::EErrorBreak:		printf("Break condition");			break;<br />
			case CSerial::EErrorFrame:		printf("Framing error");			break;<br />
			case CSerial::EErrorIOE:		printf("IO device error");			break;<br />
			case CSerial::EErrorMode:		printf("Unsupported mode");			break;<br />
			case CSerial::EErrorOverrun:	printf("Buffer overrun");			break;<br />
			case CSerial::EErrorRxOver:		printf("Input buffer overflow");	break;<br />
			case CSerial::EErrorParity:		printf("Input parity error");		break;<br />
			case CSerial::EErrorTxFull:		printf("Output buffer full");		break;<br />
			default:						printf("Unknown");					break;<br />
			}<br />
			printf(" ###\n");<br />
		}<br />
<br />
		// Handle ring event<br />
		if (eEvent & CSerial::EEventRing)<br />
		{<br />
			printf("\n### RING ###\n");<br />
		}<br />
<br />
		// Handle RLSD/CD event<br />
		if (eEvent & CSerial::EEventRLSD)<br />
		{<br />
			printf("\n### RLSD/CD %s ###\n", serial.GetRLSD()?"on":"off");<br />
		}<br />
<br />
		// Handle data receive event<br />
		if (eEvent & CSerial::EEventRecv)<br />
		{<br />
			// Read data, until there is nothing left<br />
			DWORD dwBytesRead = 0;<br />
			char szBuffer[101];<br />
			do<br />
			{<br />
				// Read data from the COM-port<br />
				lLastError = serial.Read(szBuffer,sizeof(szBuffer)-1,&dwBytesRead);<br />
				if (lLastError != ERROR_SUCCESS)<br />
					return ::ShowError(serial.GetLastError(), _T("Unable to read from COM-port."));<br />
<br />
				if (dwBytesRead > 0)<br />
				{<br />
					// Finalize the data, so it is a valid string<br />
					szBuffer[dwBytesRead] = '\0';<br />
<br />
					// Display the data<br />
					printf("%s|", szBuffer);<br />
					<br />
					// Check if EOF (CTRL+'[') has been specified<br />
					if (strchr(szBuffer,EOF_Char))<br />
						fContinue = false;<br />
				}<br />
			}<br />
		    while (dwBytesRead == sizeof(szBuffer)-1);<br />
		}<br />
	}<br />
	while (fContinue);<br />
	serial.Close();<br />
	lLastError = serial.Open(_T("COM1"),0,0,false);<br />
	if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Unable to open COM-port"));<br />
<br />
    // Setup the serial port (9600,8N1, which is the default setting)<br />
    lLastError = serial.Setup(CSerial::EBaud38400,CSerial::EData8,CSerial::EParNone,CSerial::EStop1);<br />
	if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Unable to set COM-port setting"));<br />
	return 0;<br />
}

then, what I do is following:

int __cdecl _tmain (int /*argc*/, char** /*argv*/)<br />
{<br />
    CSerial serial;<br />
	LONG    lLastError = ERROR_SUCCESS;<br />
<br />
    // Attempt to open the serial port (COM1)<br />
    lLastError = serial.Open(_T("COM1"),0,0,false);<br />
	if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Unable to open COM-port"));<br />
<br />
    // Setup the serial port (9600,8N1, which is the default setting)<br />
    lLastError = serial.Setup(CSerial::EBaud38400,CSerial::EData8,CSerial::EParNone,CSerial::EStop1);<br />
	if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Unable to set COM-port setting"));<br />
<br />
    // Register only for the receive event<br />
    <br />
<br />
    // Keep reading data, until an EOF (CTRL-Z) has been received<br />
<br />
	//lLastError = serial.Write("\n");<br />
	//Sleep(1000);<br />
lLastError = serial.Write("\nwhoami\n");<br />
int r;<br />
//r = readme(serial);<br />
if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Error sending a return"));<br />
lLastError = serial.Write("\nwhoami\n");<br />
		 <br />
r = readme(serial);<br />
if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Error sending a return"));<br />
<br />
		//r = readme(serial);<br />
<br />
		//lLastError = serial.Write("\nwhoami\n");<br />
if (lLastError != ERROR_SUCCESS)<br />
		return ::ShowError(serial.GetLastError(), _T("Error sending a return"));<br />
<br />
    // Close the port again<br />
    serial.Close();<br />
    return 0;<br />
}

ok when the first is commented out, I see the results of both functions. but when the first readme is there, it only reads up to that point, and goes no further.

why is that so? I would like to read information step by step, as it needs to processed.

thanks alot for any help

quarry

Re: read from comport problem

Bob Stanneveld28-Jul-05 19:19

Bob Stanneveld

28-Jul-05 19:19

Hello,

Put the caret next to that line and than hit "run to cursor" in your Debug menu. Second step in your code and see where your code hangs and post more specific information on your problem. Until then, most people here will not bother to look at your post with so much code.

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Re: read from comport problem

quarry_0629-Jul-05 8:15

quarry_06

29-Jul-05 8:15

hey thanks for the answer

if (strchr(szBuffer,EOF_Char))<br />
						fContinue = false;

I think the problem is, that this never happens.

so it gets stuck in this while loop, where there is a function
lLastError = serial.WaitEvent();
but nothing happens here neither. how can interupt this loop?

thanks

Re: read from comport problem

Bob Stanneveld1-Aug-05 1:01

Bob Stanneveld

1-Aug-05 1:01

Hello,

I think your problem is that you wait forever for an event. So I guess that no event arrives on your COM port and that you are stuck in the WaitEvent() function.

See if this helps:

lLastError = serial.WaitEvent(NULL /* no overlapped IO */, 100 /* wait 100 ms */);
if( lLastError == ERROR_TIMEOUT )
{
    // no event arrived in the specified time interval
}

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Web Services from VC++ 6.0

carks28-Jul-05 8:21

carks

28-Jul-05 8:21

Hi All,

Ive got a project which was developed in Visual C++ version 6.0.

Now Ive got to make it access a web service to get data from a database...

First of all im COMPLETELY ignorant on these matters, but i suppose we've all got to take the plunge sometime...

I know that in the Visual Studio .NET version there are some tools to "automatically" generate the volumes of code required to do the web service method accessing stuff, but I dont want to change to .NET just to do this little thing!

Is there a simple generalized web service accessing API which wraps all the crap required to access a web service into a few simple routines?

Ive been looking around the net but im not convinced that Ive found the perfect solution.

Thanks in advance for any pointers,

Dave

Re: Web Services from VC++ 6.0

fakefur28-Jul-05 10:05

fakefur

28-Jul-05 10:05

Search here on CP for an article by Anders Molin. It has a class that does exactly what you are looking for.

Re: Web Services from VC++ 6.0

Ravi Bhavnani28-Jul-05 10:16

Ravi Bhavnani

28-Jul-05 10:16

I wrote CWebResourceProvider[^] to solve exactly this kind of problem! You can find robust applications of this class here[^] and here[^].

/ravi

My new year's resolution: 2048 x 1536
Home | Music | Articles | Freeware | Trips
ravib@ravib.com

Help me... Rich Edit

Aqueel28-Jul-05 8:18

Aqueel

28-Jul-05 8:18

Now I am able to read data from a .rtf file and write its contents in a rich edit control. Now I want to include this .rtf file as a resourse (just like we include bitmap), to print its contents in a rich edit control. Please can anyone tell me how can i do that?

Thank you
Aqueel A. Mirza

We Believe in Excellence

Re: Help me... Rich Edit

John R. Shaw28-Jul-05 8:51

John R. Shaw

28-Jul-05 8:51

Goto the resource pane: right click on the on the root node of the list and select import.
OR
Insert->Resource->Import
OR
Ctrl+R

You should be able to figure out the rest from there.

Good Luck!

INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen

Re: Help me... Rich Edit

David Crow28-Jul-05 9:49

David Crow

28-Jul-05 9:49

Here is a somewhat related example.

"One must learn from the bite of the fire to leave it alone." - Native American Proverb

Child Dialog Background Color

liehann28-Jul-05 8:12

liehann

28-Jul-05 8:12

Hi,

I have a class derived off CDialog that I use as a child dialog in a tab control.

The problem I have is that the background of the dialog is gray but the tab control's background is white (xp look).

How can I get the child dialog's background to be the same color as the tab control's background?

I would prefer not to have to change the tab control as I'm using a class from a library and I would like to have a general solution that applies not only to tab controls but any parent window.

I tried overriding OnEraseBkgnd and calling
HBRUSH hBrush = (HBRUSH) GetParent()->SendMessage(WM_CTLCOLORDLG, m_hWnd);
and using the returned hBrush to fill the dialog's client area but that threw exceptions.

I've also tried not erasing the background.

Any help would be appreicated.

Regards,

Liehann

Re: Child Dialog Background Color

Alexander ^M.,28-Jul-05 9:32

Alexander ^M.,

28-Jul-05 9:32

The window class adjusts the (normal) background color. The easiest way to override these settings is to handle WM_ERASEBKGND with TRUE as return (to prevent flickering) and handle WM_PAINT to paint the background (e.g. CDC::FillSolidRect).

Don't try it, just do it! Wink | ;-)

Re: Child Dialog Background Color

liehann28-Jul-05 21:01

liehann

28-Jul-05 21:01

Thanks for the reply.

How can I get the parent window's background color in OnPaint?

'needs to have dll-interface' warning

Themis28-Jul-05 7:39

Themis

28-Jul-05 7:39

Hi,
I need some help with dlls. It's my first time writting dlls and I have a minor problem.

<br />
#ifdef MYPROJ_EXPORTS<br />
#define _myprojExport __declspec(dllexport)<br />
#else<br />
#define _myprojExport __declspec(dllimport)<br />
#endif<br />
<br />
class _myprojExport MyClass<br />
{<br />
...<br />
protected:<br />
	typedef std::list<std::string> StringList;<br />
	StringList mylist;<br />
};<br />

As you can see on the above code I have MyClass which is a simple class that I export. When mylist member is missing everything is compiled smoothly, however when I have mylist member variable on the class I get the following warning from my compiler (VS .NET 7.1).

warning C4251: 'MyClass::mylist' : class 'std::list<_Ty>' needs to have dll-interface to be used by clients of class 'MyClass'
with
[
_Ty=std::string
]

How can I create a dll-interface for std::list? I don't have to export std::list the client will find its implementation in <list>. How should I declare mylist in order to get rid of these warnings?

Thanks in advance,
Themis

#define a comment to remove code?

Giles28-Jul-05 6:31

Giles

28-Jul-05 6:31

Anyone know if this is possible.

I know I can define a function to do that kind of thing......

#ifdef DEBUG
# define STUFF(x) x
#else
# define STUFF(x)
#endif

but what I would like to be able to do is define something so that I could just make the compiler ignore the line.

#ifdef DEBUG
# define ONLY_DEBUG cout
#else
# define ONLY_DEBUG //
#endif

e.g. ONLY_DEBUG << "this is a debug build" << endl;

This is only an example I know I can use TRACE etc, its been able to get rid of something in debug, short of having #ifdef DEBUG around it.

Re: #define a comment to remove code?

Alexander ^M.,28-Jul-05 9:00

Alexander ^M.,

28-Jul-05 9:00

I don't think that it's possible to set a comment as define.
Why don't you create a define like that:

#ifdef _DEBUG
#define DPRINT( x ) cout << x << endl
#else
#define DPRINT( x )
#endif

Don't try it, just do it! Wink | ;-)

Re: #define a comment to remove code?

Bob Stanneveld28-Jul-05 19:21

Bob Stanneveld

28-Jul-05 19:21

Hello,

Why don't you just try it? I think that it is possible, since you canno't use '//' comments in macro's since it will erase some of your code when the preprocessor expands it to a single line...

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

modeless and modal child dialogs

23_44428-Jul-05 6:12

23_444

28-Jul-05 6:12

I'm creating a modal child dialog and a modeless child dialog to learn about them.

I have a simple SDI application that calls the dialogs.

The modal child dialog derived from CDialog opens up behind the mainframe and does not have the focus, nor is it ever able to obtain the focus once I find it, i.e. title bar remains grayed and cannot click on any buttons on the modal child dialog. Properties of the dialog are child and visible.

CModalChild cmd;
cmd.DoModal();

The modeless child dialog opens up as it should but does not have the focus nor is it ever able to obtain the focus, i.e. the title bar remains greyed although the modeless child dialog is functional.

if (!m_pModelessChildDialog)
m_pModelessChildDialog= new CModelessChild;

if (!::IsWindow(m_pModelessChildDialog->GetSafeHwnd()))
m_pModelessChildDialog->Create(IDD_DIALOG6, this);

m_pModelessChildDialog->ShowWindow(SW_SHOW);

Hope someone can help me understand this. Thanks.

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