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GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200928-Apr-08 10:19
MrFloyd200928-Apr-08 10:19 
GeneralRe: How To Connect Serial Port in MFC? Pin
CPallini28-Apr-08 10:28
mveCPallini28-Apr-08 10:28 
GeneralRe: How To Connect Serial Port in MFC? Pin
David Crow28-Apr-08 10:40
David Crow28-Apr-08 10:40 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200928-Apr-08 10:55
MrFloyd200928-Apr-08 10:55 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200928-Apr-08 11:00
MrFloyd200928-Apr-08 11:00 
GeneralRe: How To Connect Serial Port in MFC? Pin
David Crow28-Apr-08 11:06
David Crow28-Apr-08 11:06 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200928-Apr-08 11:40
MrFloyd200928-Apr-08 11:40 
GeneralRe: How To Connect Serial Port in MFC? Pin
Randor 28-Apr-08 12:42
professional Randor 28-Apr-08 12:42 
sahanaskin wrote:
When does The ERROR_INVALID_HANDLE error happen?


This happens when CreateFile() fails. Your CreateFile is probably returning INVALID_HANDLE_VALUE.

As has been previously stated, you need to call GetLastError() to see why this is occuring. Modify your code as follows:

hComm_ = CreateFile("COM1", // Specify port device: default "COM1"
GENERIC_READ | GENERIC_WRITE, // Specify mode that open device.
0, // the devide isn't shared.
NULL, // the object gets a default security.
OPEN_EXISTING, // Specify which action to take on file. 
FILE_FLAG_OVERLAPPED, // default.
NULL); // default.
if(INVALID_HANDLE_VALUE == hComm_)
{
	DWORD dwErr = GetLastError();
	LPTSTR lpMsgBuf = NULL;
	FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,NULL,dwErr,MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),(LPTSTR) &lpMsgBuf,0,NULL);
	TRACE(_T("ERROR: %s\n"),lpMsgBuf);
	LocalFree(lpMsgBuf);
}

GeneralRe: How To Connect Serial Port in MFC? Pin
CPallini28-Apr-08 21:13
mveCPallini28-Apr-08 21:13 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200928-Apr-08 23:11
MrFloyd200928-Apr-08 23:11 
QuestionRe: How To Connect Serial Port in MFC? Pin
CPallini28-Apr-08 23:45
mveCPallini28-Apr-08 23:45 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200929-Apr-08 0:11
MrFloyd200929-Apr-08 0:11 
GeneralRe: How To Connect Serial Port in MFC? Pin
CPallini29-Apr-08 0:23
mveCPallini29-Apr-08 0:23 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200929-Apr-08 0:48
MrFloyd200929-Apr-08 0:48 
QuestionRe: How To Connect Serial Port in MFC? Pin
CPallini29-Apr-08 0:54
mveCPallini29-Apr-08 0:54 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200929-Apr-08 1:24
MrFloyd200929-Apr-08 1:24 
GeneralRe: How To Connect Serial Port in MFC? Pin
CPallini29-Apr-08 1:33
mveCPallini29-Apr-08 1:33 
GeneralRe: How To Connect Serial Port in MFC? Pin
MrFloyd200929-Apr-08 1:56
MrFloyd200929-Apr-08 1:56 
GeneralRe: How To Connect Serial Port in MFC? Pin
CPallini29-Apr-08 1:58
mveCPallini29-Apr-08 1:58 
AnswerRe: How To Connect Serial Port in MFC? Pin
Hamid_RT29-Apr-08 4:09
Hamid_RT29-Apr-08 4:09 
GeneralRetrieve Win32 Process Memory Map Pin
edfgreen28-Apr-08 8:19
edfgreen28-Apr-08 8:19 
GeneralRe: Retrieve Win32 Process Memory Map Pin
Saurabh.Garg28-Apr-08 14:58
Saurabh.Garg28-Apr-08 14:58 
GeneralRe: Retrieve Win32 Process Memory Map Pin
Stephen Hewitt28-Apr-08 15:18
Stephen Hewitt28-Apr-08 15:18 
GeneralRe: Retrieve Win32 Process Memory Map Pin
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QuestionC++ image compression LZW algorithm??? Pin
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