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Hello !
Looking in the MSDN for the documentation about using timeouts with serial ports (using the COMMTIMEOUTS structure), I found this line:
A value of zero for both the ReadTotalTimeoutMultiplier and ReadTotalTimeoutConstant members indicates
that total time-outs are not used for read operations.
But what does 'total time-outs are not used' means ? Does it means that the read operation will return immediately even if no bytes were received or does it wait an infinite amount of time (till all bytes are received) ? It is not really clear...
And the same question for write timeouts.
Any idea ?
Thanks
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I am pretty sure, based on my experiences, that it means the read will WAIT nearly forever.
You really DO want some timeouts, and then just accept what characters you have and accumulate them into your own buffer until you have the desired amount of characters, or consider it an error condition if you have not received enough in the alloted time.
Same for writing. If they don't go out the port right away, in the alloted time frame, then something else is probably wrong, like the modem is off or the serial line is disconnected or something.
I would not recommend writing code that will 'wait forever' in either case if you can help it.
If you don't expect the same amount of data to be read or written constantly, there is the SetCommTimeouts() function you can call prior to each read and write. Use some math to adjust the time frame estimate based upon your current bit rate and the number of characters.
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Need to write a driver(virtual serial port driver) in C/C++ which will fit in between the applications and the USB driver, and will try to expose virtual serial ports which the application can communicate with, and internally will pass on data to the USB layer, which will communicate with the USB end of the connector.
For applications, even though the serial devices are connected through a USB interface in between, the USB interface is transparent – i.e. the applications must behave as if they are communicating with serial devices through COM ports, USB is nowhere in the picture.
Tell Me WHy
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Hello friends,
This is a reminding request, would anybody let me know how can I view a TIFF file in SDK, please, it's urgent, if possible could you send me the code? I will be grateful!!!
Thanks a million,
warm regards,
Software Developer
Sanjay Khapre
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Hi.
I am creating the Outlook Object Library 11.0's application object in C++ and calling its CreateDispatch method in an MFC Regular DLL's exproted function. When i call that function from a windows application it is working fine, but when that function is called from a windows service the CreateDispatch function of the application object fails. Please tell me what is this problem. The windows service is configuered to run with a user of windows NT domain.
Here is the code
if(objApplication.CreateDispatch("{0006F03A-0000-0000-C000-000000000046}"))
{
objNameSpace = objApplication.GetNamespace("MAPI");
if(objNameSpace!=NULL)
{
isLoggedIn=TRUE;
return TRUE;
}
}
isLoggedIn=FALSE;
return FALSE;
Common Man
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Your SERVICE might be configured to run as the user of the domain, but that does not mean that the MAPI code does not make its own calls to try to resolve the 'current user' and it does not find one logged in. I think there are articles from Microsoft and some here and there on the Internet that discuss problems with using MAPI from a service.
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It is time to admit that I am out of my element. I am new to Visual C++ .Net and need help.
How do you create and access Global Variables in a Windows Form Application. I have vaiables that I need to access from several different forms. It is possible?
Thanks
Thom
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Thanks, I am closer.
When I follow those instrutions, I place the variable (int iTest;) in a .cpp file outside form1 and form2. Also, place "extern int iTest;" in stdafx.h It allows me to assign "iTest = 6;" in form1, but when I insert "iTest = 23;" in a button_click on form2 I get: " 'iTest' : undeclared identifier" and " 'iTest' : redifinition; different basic types".
Thom
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Did you try rebuilding the application? Things in stdafx.h are precompiled and will be regenerated only by a rebuild.
Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro
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Actually ther problem I caused is that I had included the Form2 *before* I declared my global in stdafx.h. This caused the program to try and reinitialize the variable again.
Whew! I think I can actually do this!
Thanks guys, I am learning, but apparently I used punchcards to many times in the early days.
Thom
--"Late to bed, Early to rise,--
-Work like hell and Advertise."-
Wernher von Braun
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Hello, i am trying to build i client server application using winsock library but i thinkit will be easy by not using MFC.
Please give me tutorial about how to make a simple client and simple server.
At the client end i will be using GETCOmPuterNAme() and Username apis
and i want to transmit them to server.
Please help me out in this regard.
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Beej's Guide to Network Programming is the standard reference for *nix programmers learning sockets, but it is still very relevant for windows programmers as well - not to mention being far better laid out than the winsock faq
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I wanna supervise every drag_and_drop for information security...but how can i supervise it? or is it possible to prohibit of doing drag_and_drop?
Please help me to figure it out, thank you
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atsuki wrote:
or is it possible to prohibit of doing drag_and_drop?
Yes, don't call DragAcceptFiles() in the first place, or call it with FALSE.
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
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Thank you for your reply, David.
I have called DragAcceptFiles() in the first place...
However, how can i prohibit the user of doing drag and drop???
like following procedure???
1.Get ON_WM_DROPFILES() message
2.Get Droped file list
nor
1.Notice begin drag
2.Using RegisterClipboardFormat to put data into clipboard
3.EmptyClipboard()
is there any easy way to prohibit it???
thank you
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atsuki wrote:
However, how can i prohibit the user of doing drag and drop???
Call it again using FALSE. This is all spelled out in the documentation.
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
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hi alok
Thanx
Most of the tapi stuff talks in terms of telephone connected to modem and the networks.. I don't have to take into consideration the networking part of it.. In this application the telephone is connected to an adapter which is devised by the company for which i am developing the software application.. This adapter is connected to USB port.. I think i have to communicate with the standard USB driver to collect voice data from telephone..
regards
pallavi
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mpallavi wrote:
In this application the telephone is connected to an adapter which is devised by the company for which i am developing the software application..
Have company which made that adpater provided you any interface or api to communicate with there adapter!!?
[Vote One Here, Complete my Survey....]
Alok Gupta
visit me at http://www.thisisalok.tk
"I Think Believe this Will Help"
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Does the adapter show up in your phones and modems list in control panel?
- tareq
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hi
Actually the things are going on simultaneously.. The phone adapter is recognised by the standard usb driver.. hopefully).. One of my colleague is developing a client driver for it.. The interface will be provided for my application.. But i have to wait for some days ..
What i was thinking of doing is.. to program a apllication for recording voice using microphone at present..
Please suggest me how to go about this project.. I am a beginner in VC++ and this project is part of my final semester MCA course..
Ragards
pallavi
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I am trying to resize my desktop for a toolbar at the top. If I set the m_srceenrect and send either call, all is good for about a minute, then the desktop moves back up to original rect, anybody know why?
SystemParametersInfo(SPI_SETWORKAREA, 0, &m_screenrect, SPIF_SENDCHANGE);
SystemParametersInfo(SPI_SETWORKAREA, 0, &m_screenrect, SPIF_SENDWININICHANGE);
shotgun
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