C / C++ / MFC

Re: Reading and writing files to the System Directory in Windows Vista using C++, MFC and fopen

11-Nov-09 4:36

Danny Nowlan wrote:
These techniques work like a charm on my projects that I programmed using Visual C++ v6.0.

The problem has nothing to do with VS6.

Your program should not be writing/crearing files in the \Windows\System32 folder. That folder has been off limits for years, but since it has not been enforced, folks have continued to abuse it. Use SHGetFolderPath() to get the path of a folder that you can write to. For example, CSIDL_COMMON_APPDATA, CSIDL_LOCAL_APPDATA, CSIDL_COMMON_DOCUMENTS, CSIDL_PERSONAL.

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"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

Covean11-Nov-09 4:38

Covean

11-Nov-09 4:38

As normal user you will not get access to the system directory of vista.
On vista and above many security issues changed!

Try your to start your exe "as adminstrator" and you will see it will work.

Greetings
Covean

Re: Reading and writing files to the System Directory in Windows Vista using C++, MFC and fopen

Rolf Kristensen11-Nov-09 9:19

Rolf Kristensen

11-Nov-09 9:19

Could you explain why you need to read/write files in the System32 directory ?

There is a reason why Microsoft tries to protect its system directories.

Re: Reading and writing files to the System Directory in Windows Vista using C++, MFC and fopen

D_code_writer11-Nov-09 22:56

D_code_writer

11-Nov-09 22:56

Hey Snakefoot,

I use it as a convenient location to keep operating files without bothering with the registry. Let me give an assurance that I am not in the business of writing viruses or Malware. They may have the best of intentions, but people like this cause alot more harm than they do good.

Danny

Re: Reading and writing files to the System Directory in Windows Vista using C++, MFC and fopen [modified]

Rolf Kristensen11-Nov-09 23:10

Rolf Kristensen

11-Nov-09 23:10

When you mean operating file, then I guess you mean data files that belongs to your application. Such files should not be placed in the Windows-directory.
What if another application suddenly decides to also use this location, and by mistakes uses your filename-format ?

You should read this guide from Microsoft Data and Settings Management[^] (Though written for Win2k, then it also holds for Vista/Win7)

TCHAR szAppData[MAX_PATH];
...
hr = SHGetFolderPath(NULL, CSIDL_APPDATA, NULL, 0, szAppData);
PathAppend(szAppData, "Company\Product\File.txt")

CSIDL_APPDATA - Per user, roaming [user profile]\Application data
CSIDL_LOCAL_APPDATA - Per user, non-roaming [user profile]\Local Settings\Application data
CSIDL_COMMON_APPDATA - Hidden folder for normal users. Per machine (non-user specific & non- roaming) All Users\Application data
CSIDL_COMMON_DOCUMENTS - Visible folder for normal users. Default files in this folder is readonly for other users than the creator, the application must change the security permissions on its application-folder to change this behavior. Per machine (non-user specific & non- roaming) All Users\Documents

modified on Monday, December 14, 2009 10:39 AM

CFileDialog creates problem under unicode standard

m_mun11-Nov-09 4:20

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:20

Hi all,
I am using '_UNICODE' rather '_MBCS' in my MFC single document app.
My problem code-
CString openFilePath;

CFileDialog fileOpen(true, NULL, NULL, NULL, L"Text file(.txt)||*.txt", NULL);
openFilePath = fileOpen.GetPathName(); //it returns CString

'GetPathName()' returns just a single charecter. When i use '_MBCS' it returns full file path.

I want unicode standard with full file path when i open a file using "CFileDialog".

Thanks

David Crow11-Nov-09 4:28

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:28

Shaheen.India wrote:
'GetPathName()' returns just a single charecter. When i use '_MBCS' it returns full file path.

How are you verifying this?

Shaheen.India wrote:
I want unicode standard with full file path when i open a file using "CFileDialog".

CFileDialog does not open files. It merely allows you to select them.

m_mun11-Nov-09 4:30

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:30

Verifying in Debug mode. It sends a single character as a string. When i open a file, if it belongs like "e:\MyData\aa.txt", it returns just "e" as string

David Crow11-Nov-09 4:32

Re: CFileDialog creates problem under unicode standard [modified]

11-Nov-09 4:32

Which does not answer my question. If you are using the Watch window, then you'll need to use the ,su symbol to see Unicode strings. Otherwise, you're just going to see a single character.

m_mun11-Nov-09 4:34

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:34

Using object of CFileDialogIt sends a single character as a string. When i open a file, if it belongs like "e:\MyData\aa.txt", it returns just "e" as string.

OK. How can i get open file path?

modified on Wednesday, November 11, 2009 10:41 AM

David Crow11-Nov-09 4:42

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:42

Shaheen.India wrote:
When i open a file, if it belongs like "e:\MyData\aa.txt", it returns just "e" as string

This makes no sense. You've shown no code that opens a file, only code that selects a file. What's the "it" that you are referring to?

You would receive more reliable help if you'd post the actual code that you are commenting on or asking a question about.

m_mun11-Nov-09 4:46

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:46

OK. Can i get full file when i open a file using 'CFileDialog's constructor?

m_mun11-Nov-09 4:55

Re: CFileDialog creates problem under unicode standard

11-Nov-09 4:55

This is my simple code:

CString openFilePath;

CFileDialog fileOpen(true, NULL, NULL, NULL, L"Text file(.txt)||*.txt", NULL);
if(fileOpen.DoModal() == IDOK)
{
openFilePath = fileOpen.GetPathName();//Here is a break point. at this stage //value of openFilePath display like {"e"} only.
..
..
}

David Crow11-Nov-09 5:14

Creating a expert system and need some help please

11-Nov-09 5:14

Shaheen.India wrote:
openFilePath = fileOpen.GetPathName();//Here is a break point. at this stage //value of openFilePath display like {"e"} only.

See here.

akshay174111-Nov-09 4:19

akshay1741

11-Nov-09 4:19

Hello guys,

Im new to this forum and this is my first post!!!

I am a beginner at this and need some help with my first project.

Basically i am looking to create a expert car system..which works as follows:

a user will be able to input natural english text into the system...for example 'i want a blue honda with a 1.6 engine'

the system should read the text and cleverly extract the key words such as 'blue' 'honda' '1.6'

as soon as the words are matched, c++ will add these values in my database in mysql

if there are any missing values then the system should ask the user.. so:

tables:
colour table - blue
car table - honda
model table - ?
engine table - 1.6

so becuase the model table is missing maybe the system can ask the user..'how about the model?'

and evetually one the tables are filed the sql wil run and find matching cars and the output will be shown in c++.

okay so this is my plan..what do you guys think??

stupid plan?

i just need help trying to design this program.

any ideas or suggestions will help. like how do i go about creating sets of colours in c++ so when the user types in the text i can match the colour from his text to my set and send it up to the sql database?

Thanks guys Smile | :)

Re: Creating a expert system and need some help please

Richard MacCutchan11-Nov-09 7:48

Richard MacCutchan

11-Nov-09 7:48

akshay1741 wrote:
any ideas or suggestions will help. like how do i go about creating sets of colours in c++ so when the user types in the text i can match the colour from his text to my set and send it up to the sql database?

You will need a list, array or table of some form with all the valid colours held as strings. Then when the user enters the deatails you need to parse the input and look for a word that matches any of your colours, not forgetting to allow for upper, lower or mixed case.

From your opening statement I would suggest you get comfortable with the basics of C++ before trying to create the project you describe above.

Re: Creating a expert system and need some help please

Maximilien11-Nov-09 9:44

Maximilien

11-Nov-09 9:44

akshay1741 wrote:
cleverly extract the key words

ok, that is not simple; but people have been doing this for a while, but it's not easy.

Parsing, even simple, natural language is difficult.

If you want to simple extract strings from any input and match them to table that's easy, but that's no expert system.

for example "bla bla 1.6 blue fox jumps over the honda but his engine is sick"...

you will need to tokenize (keyword here) the input string and take each token and do a search into a table.

Good luck.

This signature was proudly tested on animals.

Intercepting the TerminateProcess event

Krischu11-Nov-09 4:09

Krischu

11-Nov-09 4:09

In the vein of my CreateProcess() question in a parallel thread today I'm facing the problem
of letting the called subprocess doing some tidying up work before really following the termination signal.

Would that be possible? Or would it be better to send the process a different signal
(in UNIX that would have been a USR signal) and wait a time period for receiving the termination event and if that does not occur in time, then terminating it brute force?

Is the TerminateProcess an unconditional signal that cannot be intercepted by the process
under termination itself? Hope I expressed myself clearly enough Smile | :)

--
Christoph

Covean11-Nov-09 4:23

Covean

11-Nov-09 4:23

Have you control about the subprocess?
If so why not use named events?

HANDLE hEvent = CreateEvent(NULL, true, false, "some_silly_name_you_can_refer_to_in_your_processes");

You can use this in your service and your subprocess.
If an event with this name does not exists in the system it will be created, if
it exists, you get the same handle as the first application who called CreateEvent with this
name. Now you can interact with your subprocesses.

Greetings
Covean

Krischu11-Nov-09 5:50

Krischu

11-Nov-09 5:50

Covean wrote:
Have you control about the subprocess?
If so why not use named events?

HANDLE hEvent = CreateEvent(NULL, true, false, "some_silly_name_you_can_refer_to_in_your_processes");

Thanks. Yes, I have control of the process' source code. Will try something in that vein.

--
Christoph

Covean11-Nov-09 21:19

Covean

11-Nov-09 21:19

In general I do not post my own code but doing some IPC-stuff is not such a secret. Laugh | :laugh:

Here is a dll I wrote to communicate between 2 apps.
The one site calls
      GetFaceDetectionStatusChangedEventHandle(),
      CreateFaceDetectionStatusMapFile(),
      and GetCurrentFaceDetectionStatus() and closes it if it doesnt need it anymore.
the other site calls SetFaceDetectionStatus() instead of GetCurrentFaceDetectionStatus().

This code shows how to wait in one app for another and how to transfer
data from one app to the other by using shared memory.

Note: I left the german comments in for you.

------------------------------------------------------------------------------------------
fdinterop.h

#pragma once
#define WINVER 0x0501
#define _WIN32_WINNT 0x0501
#define _WIN32_WINDOWS 0x0410 
#define _WIN32_IE 0x0600
#define WIN32_LEAN_AND_MEAN

#include <windows.h>

////////////////////////////////////////////////////////////////////////////////////
// Konstanten //////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////

TCHAR szEventName[]=TEXT("FDInteropDllFaceDetectionStatusChanged");
TCHAR szMapFileName[]=TEXT("FDInterOpDLLFaceDetectionMapFile");

////////////////////////////////////////////////////////////////////////////////////
// Strukturen //////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////

// FaceDetectionStatus Hauptobjekt
typedef struct _fdsObject
{
     DWORD     dwTimeStamp;
     BOOL     bFaceDetected;
     INT          nX1;
     INT          nY1;
     INT          nX2;
     INT          nY2;
} FDS_OBJECT, *PFDS_OBJECT, NEAR *NPFDS_OBJECT, FAR *LPFDS_OBJECT;

////////////////////////////////////////////////////////////////////////////////////
// exportierte Funktionen //////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////

// Gibt das Handle auf das systemweite, benannte Event zurück, welches ausgelöst wird, wenn mit
// SetFaceDetectionStatus neue Daten an den "wartenden" Prozess geschickt werden.
HANDLE _declspec(dllexport) __stdcall GetFaceDetectionStatusChangedEventHandle();

// Gibt das Event, dass mit GetFaceDetectionStatusChangedEventHandle geöffnet wurde, wieder frei.
void _declspec(dllexport) __stdcall CloseFaceDetectionStatusChangedEventHandle(HANDLE hFaceDetectionStatusChangedEventHandle);

// Gibt eine Handle auf einen prozessübergreifenden gemeinsamen Speicherbereich zurück.
HANDLE _declspec(dllexport) __stdcall CreateFaceDetectionStatusMapFile();

// Dekrementiert den Zähler, der angibt wieviele Prozesse derzeit auf den prozessübergreifenden gemeinsamen Speicherbereich zugreifen.
// Wird der Zähler auf 0 dekrementiert, so wird auch der Speicherbereich freigegeben.
void _declspec(dllexport) __stdcall CloseFaceDetectionStatusMapFile(HANDLE hFaceDetectionStatusMapFile);

// Versucht die aktuellen Werte der Gesichtserkennung aus dem prozessübergreifenden gemeinsamen Speicherbereich auszulesen
// und kopiert bei Erfolg die Werte in den Buffer pFDSObject.
// Sollte hFaceDetectionStatusMapFile oder pFDSObject NULL sein gibt die Funktion auf jeden Fall FALSE zurück.
BOOL _declspec(dllexport) __stdcall GetCurrentFaceDetectionStatus(HANDLE hFaceDetectionStatusMapFile, LPFDS_OBJECT pFDSObject);

// Setzt den aktuellen Status der Gesichtserkennung.
// Wird für bFaceDetected der Wert 0 angegeben, so bedeutet dies, daß zur Zeit kein Gesicht erkannt wird, jeder andere Wert entspricht einem
// erkannten Gesicht.
// Die Werte X1, Y1, X2, Y2 stellen die Koordinaten des Rechtecks dar in dem die Gesichtserkennung vermutlich ein Gesicht erkannt hat.
void _declspec(dllexport) __stdcall SetFaceDetectionStatus(INT bFaceDetected, INT nX1, INT nY1, INT nX2, INT nY2);

------------------------------------------------------------------------------------------
fdinterop.c

#include "fdinterop.h"

/////////////////////////////////////////////////////////////////////////////////////
//// DLL Hauptfunktion //////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

BOOL __stdcall DllMain(HANDLE hModule, DWORD dwReasonForCall, LPVOID lpReserved)
{
     switch(dwReasonForCall)
     {
          case DLL_PROCESS_ATTACH:
          case DLL_THREAD_ATTACH:
          case DLL_THREAD_DETACH:
          case DLL_PROCESS_DETACH:
               break;
     }
     return TRUE;
}

/////////////////////////////////////////////////////////////////////////////////////
//// GetFaceDetectionStatusChangedEventHandle ///////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

HANDLE __stdcall GetFaceDetectionStatusChangedEventHandle()
{
     return CreateEvent(NULL, TRUE, FALSE, szEventName);
}

/////////////////////////////////////////////////////////////////////////////////////
//// CloseFaceDetectionStatusChangedEventHandle /////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

void __stdcall CloseFaceDetectionStatusChangedEventHandle(HANDLE hFaceDetectionStatusChangedEventHandle)
{
     CloseHandle(hFaceDetectionStatusChangedEventHandle);
}

/////////////////////////////////////////////////////////////////////////////////////
//// CreateFaceDetectionStatusMapFile ///////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

HANDLE __stdcall CreateFaceDetectionStatusMapFile()
{
     return CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, sizeof(FDS_OBJECT), szMapFileName);
}

/////////////////////////////////////////////////////////////////////////////////////
//// CloseFaceDetectionStatusMapFile ///////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

void __stdcall CloseFaceDetectionStatusMapFile(HANDLE hFaceDetectionStatusMapFile)
{
     CloseHandle(hFaceDetectionStatusMapFile);
}

/////////////////////////////////////////////////////////////////////////////////////
//// GetCurrentFaceDetectionStatus //////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

BOOL __stdcall GetCurrentFaceDetectionStatus(HANDLE hFaceDetectionStatusMapFile, LPFDS_OBJECT pFDSObject)
{     
     LPFDS_OBJECT pFDSBuffer = NULL;
     
     if((hFaceDetectionStatusMapFile == NULL) || (pFDSObject == NULL))
          return FALSE;

     pFDSBuffer = (LPFDS_OBJECT)MapViewOfFile(hFaceDetectionStatusMapFile, FILE_MAP_ALL_ACCESS, 0, 0, sizeof(FDS_OBJECT));
     if(pFDSBuffer == NULL)
          return   FALSE;

     memcpy(pFDSObject, pFDSBuffer, sizeof(FDS_OBJECT));
     UnmapViewOfFile(pFDSBuffer);
     return TRUE;
}

/////////////////////////////////////////////////////////////////////////////////////
//// SetFaceDetectionStatus /////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////

void __stdcall SetFaceDetectionStatus(INT bFaceDetected, INT nX1, INT nY1, INT nX2, INT nY2)
{
     FDS_OBJECT fdsObject;
     LPFDS_OBJECT pFDSObject;
     HANDLE hFaceDetectionStatusMapFile = NULL;
     HANDLE hFaceDetectionStatusChangedEvent = NULL;

     fdsObject.dwTimeStamp = GetTickCount();
     fdsObject.bFaceDetected = (bFaceDetected==0) ? FALSE : TRUE;
     fdsObject.nX1 = nX1;
     fdsObject.nY1 = nY1;
     fdsObject.nX2 = nX2;
     fdsObject.nY2 = nY2;

     // ToDo: Speicherzugriffe synchronisieren (bzw. muß man das mit diesen Funktionen hier überhaupt?)
     hFaceDetectionStatusMapFile = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, szMapFileName);
     if (hFaceDetectionStatusMapFile != NULL) 
     {
          pFDSObject = MapViewOfFile(hFaceDetectionStatusMapFile, FILE_MAP_ALL_ACCESS, 0, 0, sizeof(FDS_OBJECT));                            
          if(pFDSObject != NULL)
          {
               memcpy(pFDSObject, &fdsObject, sizeof(FDS_OBJECT));
               UnmapViewOfFile(pFDSObject);
               CloseHandle(hFaceDetectionStatusMapFile);
          }
     }

     hFaceDetectionStatusChangedEvent = GetFaceDetectionStatusChangedEventHandle();
     SetEvent(hFaceDetectionStatusChangedEvent);
     CloseFaceDetectionStatusChangedEventHandle(hFaceDetectionStatusChangedEvent);
}

;

I hope this gives you a clue how to do this.
But be aware of the data transfer between the two apps, cause I do not lock the memory
for writing or reading (I didn't needed it, functions were only call in cylce of 40 ms).

Greetings
Covean