C / C++ / MFC

I Think I need to free Something

13-Mar-09 12:44

First, realize that not all sets of numbers can be represented by regular expressions. For example, the set of all prime integers cannot be represented as a regular expression. Now, one way to represent the set of real numbers between 143 and 163 is as follows:
143|144|145|146|147|148|149|150|151|152|153|154|155|156|157|158|159|160|161|162|163
The problem is with this approach is that the range of numbers may be quite large and the corresponding regular expression excessively large. Here is another regular expression that is
smaller for the same range:
143|144|145|146|147|148|149|15(0|1|2|3|4|5|6|7|8|9)|160|161|162|163
I am thinking with this as a start, you can develop an algorithm for an arbitrary range and the regular expression is not going to be so big as to be unmanageable.

I hope I helped you and feel free to ask a follow up question.

Bob

Re: Regular expression

Demian Panello13-Mar-09 14:19

Demian Panello

13-Mar-09 14:19

Thanks Bob.

Well, that kind of stuff that you mention is what I used to do for every range, and there is always a solution. But, I just wonder if already exist a general way to solve this kind of problems.
I'm thinking to write a program (maybe in C++ or C#) that help me in my job to proccess these ranges.
Something like you enter a range of long numbers and then the programa list you all the regular expressions that help you to locate a value within that range.

Thank you very much for your help.

BobInNJ13-Mar-09 11:38

13-Mar-09 11:38

I am writing an application using C++ and MFC. Please consider the following routine:

<br />
HBRUSH<br />
CMainWindow::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)<br />
{<br />
	HBRUSH hbr = CFrameWnd::OnCtlColor(pDC, pWnd, nCtlColor);<br />
	if (pWnd->GetDlgCtrlID() == 2500 )   {<br />
		// Set the background mode for text to transparent<br />
		hbr = CreateSolidBrush(RGB(255, 255, 255));<br />
		pDC->SetBkColor( RGB( 255, 255, 255 ) );<br />
		// pDC->SetBkMode(TRANSPARENT);<br />
		return hbr;<br />
		<br />
	}<br />
	return hbr;<br />
}<br />

This routine is called via a message block. My belief is that ever time this routine is called, a new brush is created and it is not freed/deleted. I believe the routine should freeing/deleting the brush and I would like to know how to free/delete it.

Thanks

Bob

Stuart Dootson13-Mar-09 13:54

13-Mar-09 13:54

Yes, you ought to free the brush. Now, GDI might re-use the same brush for all solid white brushes (in which case you'll only ever create one brush), but you're probably better off creating the brush in your OnInitDialog method, assigning it to a data member and returning that from this method. You can delete that brsh in an OnClose handler or something like that.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

BobInNJ14-Mar-09 13:16

14-Mar-09 13:16

Stuart,

Thanks for the response. However this code is not part of a class derived from CDialog therefore, I do have a call to OnInitDialog. The base class is CFrameWnd and I was going to create the Brush when the window is first created. That is, I was going to do it in OnCreate(). Do you see any problems with that?

Now in terms of deleting the brush, can I do that by simply using the C++ operator delete? It seems to me that there should be a MFC method to delete a brush, but I can not seem to find it. I am hoping that you will tell me what it is?

Thanks

Bob

Stuart Dootson14-Mar-09 13:24

14-Mar-09 13:24

BobInNJ wrote:
That is, I was going to do it in OnCreate(). Do you see any problems with that?

Should be fine

BobInNJ wrote:
Now in terms of deleting the brush, can I do that by simply using the C++ operator delete? It seems to me that there should be a MFC method to delete a brush, but I can not seem to find it. I am hoping that you will tell me what it is?

The CBrush destructor (well, actually, the destructor of its base class, CGDIObject) deletes the GDI object. All you need to do is make sure the CBrush is destructed properly.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

BobInNJ14-Mar-09 14:16

14-Mar-09 14:16

Stuart,

First, I believe that you have solved my problem (my testing is still incomplete as I write this) and I thank you for it. However, I am still confused about deleting the Brush. I believe you saying that if I created the brush by using the statement:
backGroundBrush = CreateSolidBrush(RGB(255, 255, 255));
where backGroundBrush is an data member of my class CMainWindow. Now, if I have an instance of CMainWindow and delete is called on the instance of CMainWindow, then the corresponding constructor for backGroundBrush will be called which will result in the brush being cleaned up. Therefore everything will work. Do I have this right?

Thanks

Bob

Stuart Dootson14-Mar-09 18:53

Memory Leakege Reporting without line number

14-Mar-09 18:53

Yes, that's correct. It uses a well-known C++ idiom called 'Resource Acquisition is Initialisation', or RAII[^].

Basically, this translates to "If you can tie the lifetime of some resource (like a BRUSH) ot a C++ object, you can allocate the resources in the constructor[^] and deallocate it in the destructor".

Unfortunately, the MFC documentation for MFC GDI object wrappers doesn't explicitly say "the GDI object is deleted in the CGDIObject destructor" - the closest it comes is in the description of using a GDI object allocated on the stack - "Allow the frame-allocated graphic object to be deleted automatically when the scope is exited"[^]. This advice holds just as true for a GDI object that is a data member of a class instance.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Member 349347313-Mar-09 11:09

Member 3493473

13-Mar-09 11:09

Hello,

I used Visual Studio's tools for reporting memory leaks.

Main program uses a dll. In main program it reports the file name and line number:

d:\tmp\ali\ali\ali.cpp(47) : {200} client block at 0x003A84C0, subtype 0, 5000 bytes long.
Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD

but in dll it doesn't:

{199} normal block at 0x003AC018, 10000 bytes long.
Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD

This style reporting isn't usefull for me.

What's wrong here. How can i fix this problem.

thanks!!

Exe Source Code:

#include "stdafx.h"

#ifdef _DEBUG
   #define DEBUG_CLIENTBLOCK   new( _CLIENT_BLOCK, __FILE__, __LINE__)
#else
   #define DEBUG_CLIENTBLOCK
#endif // _DEBUG

#if defined(_DEBUG) && defined(WIN32)
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#endif

#include <windows.h>
#include <conio.h>


#ifdef _DEBUG
#define new DEBUG_CLIENTBLOCK
#endif



int _tmain(int argc, _TCHAR* argv[])
{
	_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
	HINSTANCE m_kutuphane = LoadLibrary(L"DebugDLL.dll");

	typedef __declspec(dllimport) void __stdcall MyDllFunction();
        
    char	getDllFunctionName[]="?dllFunction@@YAXXZ";
    
    
    MyDllFunction*  mf = NULL;
    
    
    
    mf = (MyDllFunction *) GetProcAddress(m_kutuphane,getDllFunctionName);
    
    
    mf();

    new char[5000];

    while (!_kbhit());

    return 0;
}
</conio.h></windows.h></crtdbg.h></stdlib.h>

Dll Source Code:

// Check for memory leaks

#if defined(_DEBUG) && defined(WIN32)
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#endif

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{

	//_crtBreakAlloc = 1397;
_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
    return TRUE;

	new char[10000];
}

__declspec( dllexport ) void dllFunction() 

{
	std::cout << "dll: Hello!" << std::endl;
	//Memory leakage
	new char[10000];
	
}</crtdbg.h></stdlib.h>

Output :

'ali.exe': Loaded 'D:\tmp\ali\debug\ali.exe', Symbols loaded.
'ali.exe': Loaded 'C:\WINDOWS\system32\ntdll.dll', No symbols loaded.
'ali.exe': Loaded 'C:\WINDOWS\system32\kernel32.dll', No symbols loaded.
'ali.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.VC80.DebugCRT_1fc8b3b9a1e18e3b_8.0.50727.762_x-ww_5490cd9f\msvcr80d.dll', Symbols loaded.
'ali.exe': Loaded 'C:\WINDOWS\system32\msvcrt.dll', No symbols loaded.
'ali.exe': Loaded 'D:\tmp\ali\debug\DebugDLL.dll', Symbols loaded.
'ali.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.VC80.DebugCRT_1fc8b3b9a1e18e3b_8.0.50727.762_x-ww_5490cd9f\msvcp80d.dll', Symbols loaded.
Detected memory leaks!
Dumping objects ->
d:\tmp\ali\ali\ali.cpp(47) : {200} client block at 0x003A84C0, subtype 0, 5000 bytes long.
Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD
{199} normal block at 0x003AC018, 10000 bytes long.
Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD
Object dump complete.
The program '[5988] ali.exe: Native' has exited with code 0 (0x0).

Compiler settings:

Exe:

/Od /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /Gm /EHsc /RTC1 /MDd /Yu"stdafx.h" /Fp"Debug\ali.pch" /Fo"Debug\\" /Fd"Debug\vc80.pdb" /W3 /nologo /c /Wp64 /ZI /TP /errorReport:prompt

Dll:

/Od /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /D "_USRDLL" /D "DEBUGDLL_EXPORTS" /D "_UNICODE" /D "UNICODE" /D "_WINDLL" /Gm /EHsc /RTC1 /MDd /Yu"stdafx.h" /Fp"Debug\DebugDLL.pch" /Fo"Debug\\" /Fd"Debug\vc80.pdb" /W3 /nologo /c /Wp64 /ZI /TP /errorReport:prompt

Linker settings:

Exe:

/OUT:"D:\tmp\ali\Debug\ali.exe" /INCREMENTAL /NOLOGO /MANIFEST /MANIFESTFILE:"Debug\ali.exe.intermediate.manifest" /DEBUG /PDB:"d:\tmp\ali\debug\ali.pdb" /SUBSYSTEM:CONSOLE /MACHINE:X86 /ERRORREPORT:PROMPT kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib

Dll:

/OUT:"D:\tmp\ali\Debug\DebugDLL.dll" /INCREMENTAL /NOLOGO /DLL /MANIFEST /MANIFESTFILE:"Debug\DebugDLL.dll.intermediate.manifest" /DEBUG /PDB:"d:\tmp\ali\debug\DebugDLL.pdb" /SUBSYSTEM:WINDOWS /MACHINE:X86 /ERRORREPORT:PROMPT kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib

Re: Memory Leakege Reporting without line number

Stuart Dootson13-Mar-09 13:50