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LunaticFridge,
Thanks for your help. I understand what you are saying about GetLastError. And reading Microsoft's documentation about it makes it seem even less useful. It may be helpful like you say if you already know the API call is failing.
The few places where I want to be aware of failure I put something like this in:
if (DeviceDetected == FALSE)
DisplayData("Device not detected");
else
DisplayData("Device detected");That way I know for sure what the results of a call are.
Again, thanks to you and the others for your help.
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LunaticFringe wrote: That's not the point.
Very well said.
LunaticFringe wrote: GetLastError returns valid information from the last API call that failed; you're interrogating it when the last call succeeded. Not surprisingly, it returns gibbersih.
That's not completely true.In spite of the function name (GetLastError), when a API call succeedes, it often sets last error to 0. Hence, when a API call succeedes and GetLastError is different from zero, the odds are that it refers to an error occurred in a previous API call. That, however, doesn't change the prescription: "use GetLastError just when a API call fails".
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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As L u n a t i c F r i n g e already noted, that's not the point: since CreateFile does NOT fail, hence GetLastError is reporting an error coming from a previous API call (which one?!).
Your approach to error handling is wrong: you've to:
- First and always check
API return value. - Then (if the
API call failed) call GetLastError to retrieve additional information.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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CPallini wrote: First and always check API return value.
Then (if the API call failed) call GetLastError to retrieve additional information.
which is what I said - I think - maybe convoluted (just been drinking French Red wine I bought back from my last trip)
come sta Carlo ?
'g'
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Garth J Lancaster wrote: come sta Carlo ?
Bene, grazie!
E tu?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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CPallini wrote: E tu?
Non c'è male, grazie
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If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Yes, but you should call GetLastError IMMEDIATELY after it (and immediately before it to clear Previous Errors) Pass the return value of GetLastError to your Error Display function if things go sour!
The way you did it, you have NO guarantee that other API functions are NOT called, before your Display function calls GetLastError().
Regards,
Bram van Kampen
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You do not show the code for the DisplayLastError() function. I also wonder why you are casting a character constant to a CString. Chances are that one of these two is causing the erroneous message.
MVP 2010 - are they mad?
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2buck56 wrote: Does anyone know what I must do to eliminate the message from GetLastError?
First, CreateFile() is not a boolean function so checking its return value as such is wrong. Second, you need to call GetLastError() as soon as the error is detected, like:
DeviceHandle = CreateFile(detailData->DevicePath,
0,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL);
if (DeviceHandle == INVALID_HANDLE_VALUE)
{
LPVOID lpMsgBuf;
FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &lpMsgBuf,
0,
NULL);
...
LocalFree(lpMsgBuf);
}
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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DavidCrow wrote: First, CreateFile() is not a boolean function
Good point, indeed.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Richard this is the code for DisplayLastError:
void CHIDTest2008Dlg::DisplayLastError(CString Operation)
{
LPVOID lpMsgBuf;
USHORT Index = 0;
CString strLastError;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &lpMsgBuf,
4096,
NULL
);
strLastError = Operation + (LPCTSTR)lpMsgBuf;
strLastError.TrimRight();
Index = m_ResultsList.InsertString(-1, strLastError);
ScrollToBottomOfListBox(Index);
LocalFree(lpMsgBuf);And I believe you are correct in saying that the CString cast is causing the error. If I call GetLastError immediately after entering my OnBnClick funtion I get the error. At that point no API call has been made (other than the ones the system is doing). Also, by turning off unicode and going to MBCS, all the error messages disappeared. That points to the CString cast.
Ian, the code you show is the way I am doing it now. Since none of my API calls are failing I am not getting any error messages.
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Hi everyone. I'm a newbee that's exhausted the Internet already, so I joined the forum.
I'm attempting to create a file on the Desktop under the Vista environment, which is not user dependent. e.g
ofstream file;
file.open("c:\\%userprofile%\\Desktop\\report.txt");
if (!file){
cerr <<"Unable to open file report.txt";
exit(1);
}
but cannot seem to make this happen on the c drive (desktop).
Thanks in advance.
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You should be able to just call %userprofile%\desktop without having the c:\ at the front. if you open your command prompt and type in %userprofile% it'll then give you an error message but it will expand the %userprofile% to it's actual value.
Hope that helps
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CoderGirl42 wrote: ...but it will expand the %userprofile% to it's actual value.
Unless it contains spaces.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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I see the expansion in which you are speaking of from the cmd window. However, since %userprofile% yields the msg. "...' is not recognized as an internal or external command, operable program or batch file.", I'm wondering if this is the same reason %userprofile% does not work from within my program. I'm beginning to think it's the vista platform 
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Yes, I've tried various forms... e.g. without c:\ without success...
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Maybe stupid but if you open a DOS-window and type in SET (enter) is your userprofile there?
Rozis
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Sorry to say this but I believe you are misunderstanding the use of environment variables.
Apart from the fact that the string you are using is wrong ( the variable already contains the drive letter and as already pointed out may contain spaces) do you know the call you are making with apply environment variable expansion?
I prefer not to leave things to chance by either calling,
ExpandEnvironmentStringsForUser - "http://msdn.microsoft.com/en-us/library/bb762275(VS.85).aspx"
or
SHGetFolderPath - "http://msdn.microsoft.com/en-us/library/bb762181(VS.85).aspx"
Alan
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I am trying to build a application consists of four dialogs(Dialog A, dialog B, Dialog C and Dialog D).
In dialog A is you press next button it will go to dialog B, at dialog B if you press cancel button it will go back to dialog A. If next button of dialog B is clicked then it will proceed to dialog C and so on.
For the last dialog, Dialog D, if the Finish button is clicked, it will go back to dialog A.
How can I link all the dialogs to work in the sequence specified.
Should I add dialog B,C,D as custom dialog to dialog A?
In dialog A I wrote the code shown below.where is member variable of CtryDlg which declared as CBDlg type.
/*tryDlg.cpp*/
#include "BDlg.h"
void CtryDlg::OnNext()
{
int nRet = m_dBDlg.modal();
}
In dialog B,
void CBDlg::OnCancelB()
{
int nRet = 5;
EndDialog(nRet);
return;
}
But I keep getting Debug Assertion Failed error when the next button of Dialog A is clicked.
Can someone give me so suggestions?
Thanks.
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If you can use Maximilien's suggestion, override CPropertyPage::OnWizardFinish() and return FALSE to keep the sheet open. Then call the sheet's SetActivePage() method.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Run it in an External Function:
{
label1:
DlgA dlga;
if(dlga.DoModal()==IDCANCEL)return;
label2:
DlgB dlgb;
if(dlgb.DoModal()==IDCANCEL)goto label1;
label3:
DlgC dlgc;
if(dlgc.DoModal()==IDCANCEL)goto label2;
etc..
}
Regards, 
Bram van Kampen
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I need to find out what version of windows is running - Vista/Win7/XP and then get a list of processes. So far, for the list of processes I've got this:
bool isRunning(std::string pName)
{
unsigned long aProcesses[1024], cbNeeded, cProcesses;
if(!EnumProcesses(aProcesses, sizeof(aProcesses), &cbNeeded))
return false;
cProcesses = cbNeeded / sizeof(unsigned long);
for(unsigned int i = 0; i < cProcesses; i++)
{
if(aProcesses[i] == 0)
continue;
HANDLE hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, 0, aProcesses[i]);
char buffer[50];
GetModuleBaseName(hProcess, 0, buffer, 50);
CloseHandle(hProcess);
if(pName == std::string(buffer))
return true;
}
return false;
}
This is supposed to get a list of processes, then return true if process X is running. But in Windows 7 it never returns true. Developing cross platform code for windows machines is getting as bad as Linux now. I'm fairly new to windows coding and I'm finding it nightmarish.
Thanks in advance.
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int_80 wrote: if(pName == std::string(buffer))
Have you set a breakpoint on this statement to see the value of pName and buffer? Maybe it's an upper/lower case issue.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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