ATL / WTL / STL

Joaquín M López Muñoz6-Oct-04 12:56

6-Oct-04 12:56

Read Michael Dunn's post in the thread "ATL / STL : Dumb question maybe" just a few lines below Smile | :)

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
Want a Boost forum in Code Project? Vote here[^]!

Polite Programmer6-Oct-04 13:05

Polite Programmer

6-Oct-04 13:05

Thanx a lot... You guided me well... However, Just few more questions... What are the benifits of using WTL over MFC?(if any...) Moreover, I am learning MFC... Any tips to minize the learning curve will be helpfull, Also, when it is a good time to learn ATL?
Lastly, How you see the future of MFC/ATL/VC++ in the world of .NET (especially, please consider the 'interpreted' nature of .NET...)

Moreover, if Microsoft is not maintaining WTL, then who is?
Polite Programmer

More Object Oriented then C#

Joaquín M López Muñoz6-Oct-04 13:20

6-Oct-04 13:20

First of all, I know very little about ATL, so some of my responses are tentative at best.

What are the benifits of using WTL over MFC?

It is cleaner, it does not suffer from some design defects affecting MFC (most notably in multithreading issues) and does not impose a complete framework on you (that meaning, you can add just a bit of WTL to an otherwise perfectly regular Win32. MFC, OTOH, forces you to write the whole app according to the framework it provides.)
On the cons side, WTL does not provide you with wizards (I think) and it is somewhat harder to learn, as the tecnhiques it relies on are more advanced.

Also, when it is a good time to learn ATL?

I couldn't say. Probably, knowing some UI stuff (plain Win32 or MFC) before delving into WTL is good.

Lastly, How you see the future of MFC/ATL/VC++ in the world of .NET (especially, please consider the 'interpreted' nature of .NET...)

I think WTL just does not apply to .NET UI.

Moreover, if Microsoft is not maintaining WTL, then who is?

http://sourceforge.net/projects/wtl/[^]

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
Want a Boost forum in Code Project? Vote here[^]!

ATL 2-byte leak, i'm embarassed

toxcct6-Oct-04 22:50

toxcct

6-Oct-04 22:50

MFC is not only a set of classes, it is an entiere framework.

if you plan to program a console based program, you won't use MFC...

more, STL (standard template library) provides a collection of containers and algorythms that permit to manipulate every types (it is the purpose of the templates).

TOXCCT >>> GEII power

Eugene Homyakov6-Oct-04 5:28

Eugene Homyakov

6-Oct-04 5:28

I found 2-byte leak in my application, and trying to detect it I cut everything except this:

class CMyWindow : public CWindowImpl<CMyWindow>
{
public:
    // Optionally specify name of the new Windows class
    DECLARE_WND_CLASS("MyName") 
    // If this macro is not specified in your
    // class, ATL will generate a class name

    BEGIN_MSG_MAP(CMyWindow)
        MESSAGE_HANDLER(WM_PAINT, OnPaint)
    END_MSG_MAP()

    LRESULT OnPaint(UINT nMsg, WPARAM wParam, 
    LPARAM lParam, BOOL& bHandled)
    {
        // Do some painting code
        return 0;
    }
};

//
extern "C" int WINAPI _tWinMain(HINSTANCE /*hInstance*/, HINSTANCE hPrevInstance, 
                                LPTSTR /*lpCmdLine*/, int nShowCmd)
{
#ifdef _DEBUG
    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF);
#endif
    {
        ATLASSERT(AUX_SUCCEEDED(OleInitialize(0) == S_OK));
        AtlAxWinInit();
        //srand(GetTickCount());
        {
            //CAdvantageApp _AtlModule;

            CMyWindow w;
            w.Create(0, 0, 0, WS_OVERLAPPEDWINDOW);
            w.DestroyWindow();

            //_AtlModule.Run();
        }
        AtlAxWinTerm();
        OleUninitialize();
    }
#ifdef _DEBUG
    if (_CrtDumpMemoryLeaks())
        ::MessageBeep(MB_ICONEXCLAMATION);
#endif
}

The following dump is written to output:

Detected memory leaks!
Dumping objects ->
{49} normal block at 0x00944D70, 2 bytes long.
 Data: <  > DA C2 
Object dump complete.

When I comment out w.Create(0, 0, 0, WS_OVERLAPPEDWINDOW); leak disappears.

Then I created another program, almost the same:

#define WIN32
#define _WINDOWS
#define _CRTDBG_MAP_ALLOC
#define _ATL_MIN_CRT
#define _DEBUG
#include <windows.h>
//#include <stdlib.h>
//#include <crtdbg.h>
#include <comutil.h>
#include <stdio.h>
#include <tchar.h>

#include <atlbase.h>
#include <atlwin.h>

#include <windows.h>

// this code is from MSDN
// ms-help://MS.MSDNQTR.2003APR.1033/vccore/html/_atl_Implementing_a_Window_with_CWindowImpl.htm
// "Implementing a Window with CWindowImpl"
class CMyWindow : public CWindowImpl<CMyWindow>
{
public:
   // Optionally specify name of the new Windows class
   DECLARE_WND_CLASS("MyName")
              // If this macro is not specified in your
              // class, ATL will generate a class name

   BEGIN_MSG_MAP(CMyWindow)
      MESSAGE_HANDLER(WM_PAINT, OnPaint)
   END_MSG_MAP()

   LRESULT OnPaint(UINT nMsg, WPARAM wParam,
                   LPARAM lParam, BOOL& bHandled)
   {
      // Do some painting code
      return 0;
   }
};

//int WinMain(          HINSTANCE hInstance,
//    HINSTANCE hPrevInstance,
//    LPSTR lpCmdLine,
//    int nCmdShow
//)
extern "C" int WINAPI _tWinMain(HINSTANCE /*hInstance*/, HINSTANCE hPrevInstance,
                                LPTSTR /*lpCmdLine*/, int nShowCmd)
{
    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);
    HANDLE logFile;
    logFile = CreateFile("bstr_t_leak_LOG.txt", GENERIC_WRITE, FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
    _CrtSetReportFile(_CRT_WARN, logFile);
    _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE);
    _CrtSetReportFile(_CRT_ERROR, logFile);
    _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE);
    _CrtSetReportFile(_CRT_ASSERT, logFile);

    {
        ATLASSERT(OleInitialize(0) == S_OK);
        AtlAxWinInit();

        {
            CMyWindow w;
            w.Create(0, 0, 0, WS_OVERLAPPEDWINDOW);
            w.DestroyWindow();
        }

        AtlAxWinTerm();
        OleUninitialize();
    }

    exit(0);
}

and there is no leak!

Re: ATL 2-byte leak, i'm embarassed

unimatrics10-Oct-04 7:03

unimatrics

10-Oct-04 7:03

You can try to identify the code which allocates this particular memory block using

_CrtSetBreakAlloc(49);

where the 49 is the chunk number from the leaked memory report. In debug mode, your app will break into the debugger when it is allocated. Since the number is so low, it seems like it is constant in your application. If it isn't, it will get a little bit more complicated.

HTH

Message Map problem

qur6-Oct-04 1:11

qur

6-Oct-04 1:11

I have a Class CMyEdit which is inherit from CWindowImpl class and contains the Message Map for LButtonDown message.

Now at run time I want to attach this class with Edit box using its window handler and want to capture the LButtondown event. Problem is i am not able to capture the LButtonDown message even if CMyEdit class is attached to Edit box.

Code below show the way i am doing it.

<br />
class CMyEdit : public  CWindowImpl <CMyEdit><br />
{<br />
    BEGIN_MSG_MAP(CMyEdit)<br />
        MESSAGE_HANDLER(WM_LBUTTONDOWN, OnLButtonDown)<br />
    END_MSG_MAP()<br />
<br />
};<br />
<br />
//Now at runtime:<br />
<br />
CMyEdit oMyEdit;<br />
oMyEdit.Attach(hWdnEdit);     //Assuming hWndEdit is Edit box handler <br />
<br />

thanks
qur

Is possible to use ATL 7.0 in VC.6 ?

Rodrigo Pinto Pereira de Souza5-Oct-04 9:50

Rodrigo Pinto Pereira de Souza

5-Oct-04 9:50

Is possible to use ATL 7.0 in VC.6 ? Confused | :confused:

I want to use CRBMultiMap template, but unfortunately I had to use VC 6.0. Frown | :(

Thanks.

Rodrigo Pinho Pereira de Souza

toxcct5-Oct-04 21:26

toxcct

5-Oct-04 21:26

install the correct SDK...

TOXCCT >>> GEII power

Kevin McFarlane9-Oct-04 4:13

Kevin McFarlane

9-Oct-04 4:13

Will STL's multimap do what you want?

Kevin

Jörgen Sigvardsson9-Oct-04 13:15

Jörgen Sigvardsson

9-Oct-04 13:15

Yes, but it'll require the crt libraries...

--
Wir müssen leben bis wir sterben.

Kevin McFarlane10-Oct-04 0:38

Kevin McFarlane

10-Oct-04 0:38

And what's wrong with that? VC6 has them.

Kevin

key_compare problem in maps

Jörgen Sigvardsson10-Oct-04 6:30

Jörgen Sigvardsson

10-Oct-04 6:30

There's nothing wrong with them per se, unless you're trying to avoid them for size reasons.

--
Wir müssen leben bis wir sterben.

sips4-Oct-04 19:48

sips

4-Oct-04 19:48

Hi all,
I am new to STL and am developing an application that will take any kind of values as keys.But the key_compare function object is then making a comparison of the addresses of the keys rather than their values. Can somebody tell me how should i go about in my attempt to compare the values of the keys and not their addresses. Sample code below:

<code>#include<map>
#include<iostream>

int main()
{
using namespace std;
map< void*,void*,less<void*> > m1;
map< void*,void*,less<void*> >::key_compare kcl=m1.key_comp();
map< void*,void*>::iterator pIter;
char* do=new char[100];
strcpy(do,"this");//key1
char* dont="that";//value mapped with key1
m1.insert(map< void*,void*,less<void*> >::value_type(do,dont));

char* do1=new char[100];
strcpy(kc,"this");//key2
char* dont1="that";//value mapped with key2
m1.insert(map< void*,void*,less<void*> >::value_type(do1,dont1));

//problem is in next line-how do i compare the values in the keys..what
//happens now is a comparison of address
bool bresult=kcl(do,do1);//this should always return true as values
//are equal
if(bresult==true)
{
cout<<"Match";
for(pIter=m1.begin();pIter!=m1.end();pIter++)
{
cout << " " << (char *)(pIter -> first);
cout << "." << endl;
}

}
else
{
cout<<"Mismatch";
for(pIter=m1.begin();pIter!=m1.end();pIter++)
{
cout << " " << (char *)(pIter -> first);
cout << "." << endl;
}
for ( pIter = m1.begin( ) ; pIter != m1.end( ) ; pIter++ )
cout << " " << (char *)(pIter -> second);
cout << "." << endl;
}
cin.get();

}</code>

"When life offers you Lemons,Learn to make Lemonade"

Joaquín M López Muñoz4-Oct-04 20:03

4-Oct-04 20:03

As you point out yourself, having void * as the key type for your map defaults to comparing addresses instead of the contents. One easy solution is to use something better behaved as the key, like std::string (this, also, has the nice extra benefit that you are not risking storing pointers to deleted contents, as it can be the case with your current scheme.)

But I guess you have a valid reason for storing void pointers inetsad, since you talk about "an application that will take any kind of values as keys". If you absolutely need to store void pointers, how do you expect your app to work when the keys stored are of different types? (like for instance one is pointing to a char array and the other to a double)

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

sips4-Oct-04 20:36

sips

4-Oct-04 20:36

Thanks for the quick response Joaquin..Well actually i would be comparing like valued keys only(there will be a sort of switch case to compare keys of same type)so issue of keys being of different types does not affect me.This is precisely why am going for a void *.
As regards storing pointers to deleted contents,i shall be using smart pointers so that issue will also be taken care of.
What i am looking for is some kind of an overloaded function for less trait in the map that does the comparison here for the values and not the addresses.Is that possible?

Joaquín M López Muñoz4-Oct-04 21:10

4-Oct-04 21:10

Well, you can have something like this:

struct void_ptr_compare
{
  bool operator()(void* x, void* y)const
  {
    // force casting to const char *. In your general case, you'll
    // have to find out what the actual type of the arguments is.

    return strcmp((const char *)(x),(const char *)(y))<0;
  }
};
...
map< void*,void*,void_ptr_compare > m1;

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo