C / C++ / MFC

Alan Chambers31-May-02 11:07

Alan Chambers

31-May-02 11:07

Pascal was originally developed to teach programming to beginners. Although Delphi uses a far better compiler it is not as powerful as VC++. It is impossible (I believe) to add an icon to the system tray in delphi (well versions 5 and lower - if you can, how???), but obviously not in VC++, I think (having used both) that Delphi is more of a tool for programmers wanting to create windows GUI applications FAST, it is not a serious contender to the power of VC++. With this in mind I'd say Delphi is by far the best language to start learning to program and get familiar with programming concepts (pointers, data structures etc.) but if you want to be a serious programmer VC++ is eventually where you should progress to. I think Java is more of a contender to throne (but will never beat it cause you can't manipulate memory!!!).

Alan.

"When I left you I was but the learner, now I am the master" - Darth Vader

Alexandru Savescu31-May-02 12:44

Alexandru Savescu

31-May-02 12:44

Alan Chambers wrote:
It is impossible (I believe) to add an icon to the system tray in delphi (well versions 5 and lower - if you can, how???),

I doubt you cannot do that. With Delphi you can call any WIN32 API function. So if you can do it with API, you can do it with Delphi.

I believe Borland is supporting Delphi only for the language. It has behind a C++ compiler and only with a different parser. You can use C++ builder to build Delphi files also. Wink | ;)

Best regards,
Alexandru Savescu

señor codeman6-Jun-02 1:50

señor codeman

6-Jun-02 1:50

you can add icons to system tray in delphi, i was doing it in delphi 3 (because i never had delphi 2) -> i have a comjponent i wrote for it somewhere, if you are interested maybe i can dig it out (email me)

the only things C++ REALLY has over Delphi in terms of power now is templates and multiple inheritance (you can inherit from a class and an interface, but not two classes)

it's better for getting things going quick though, and it builds faster than any C++ compiler i've ever used...

as for java, it belongs steaming in my coffee cup (speaking of coffee, i could use some now Wink | ;)

)

-- señor codeman
codeman@delphidudes.com

tiaozi31-May-02 17:50

tiaozi

31-May-02 17:50

thanks for reply....

Minimal COM example

slah31-May-02 3:01

slah

31-May-02 3:01

HI
I am having problem with the minimal COM example in D. Esposito's book of Visual C++ Shell Programing. Is anybody out there who used that example. On my system it gives error of ClassFactory. Is there any solution to this problem.

GetDlgItem crashes

mikeh31-May-02 2:47

mikeh

31-May-02 2:47

I've seen this problem mentioned before, so, I'm hoping someone can help. I have a dialog that has some controls on it. In debug, the dialog works fine. However, in release mode, the code crashes on GetDlgItem. The code looks something like this:

// determine what menu item the mouse may be over.
for (n = IDC_TEAROFF_ITEM2; n<=m_lastMenuItemID; ++n)
{
pWnd = GetDlgItem(n);
pWnd->GetWindowRect(&itemRect);

The controls are all CStatics. Their ids are in sequential order. The dialog lives in a dll.

It consistently crashes on the GetDlgItem call. Anyone have an idea as to what is wrong?

TIA,
Mike

31-May-02 4:50

Have you called

AFX_MANAGE_STATE (AfxGetStaticModuleState ());

at the beginning of the DLL entry point for this code?

Ed.

mikeh31-May-02 5:00

mikeh

31-May-02 5:00

Not directly. The code is housed within a COM component that contains a doc-view framework. The user clicks a toolbar button that creates an instance of a modeless dialog. When the mouse is moved over the dialog items (ie. OnMouseMove()), the example code is triggered to determine what control the mouse is over. The error is an 005 Access Violation which usually means a bad pointer. I'm not sure why the code works fine in debug. I suspect it has something to do with the individual controls. I used classwizard to define member variables for each control. I get further into the code now, but, it still crashes later on. In release mode, it appears that the GetDlgItem() call has trouble if the control is not tied to an actual member variable.

31-May-02 5:35

Pretty sure you should use "AFX_MANAGE_STATE (AfxGetStaticModuleState ());" at the beginning of the COM call - especially if your using CWnds or resources (or any MFC!) inside a DLL.

mikeh31-May-02 7:47

mikeh

31-May-02 7:47

Thanks to Mike Collins, this problem has been solved. Here is the resolution:

My code uses many user message handlers. I typically use the ON_MESSAGE() macro with a function handler. When defining the function handler, I often code a prototype function like the following:

void OnUserHandler();

However, this is incorrect. Eventhough this code will compile (with no warnings!) and work fine in debug, it will fail in release mode. The resolution is to change the function handlers to the following:

afx_msg LRESULT memberFxn(WPARAM, LPARAM);

Hope this helps all who run across this in the future!

Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

James R. Twine31-May-02 10:33

James R. Twine

31-May-02 10:33

FWIW, the version of MFC included with VS.NET uses the casting operators to detect when signature mismatches like this occur.

Peace!

-=- James.
"Some People Know How To Drive, Others Just Know How To Operate A Car."
(Try Check Favorites Sometime!)

Munkijo31-May-02 2:01

Munkijo

31-May-02 2:01

I have a CString type variable with a large HTML file in it. When I attempt to replace all occurrances of a character with another characer, it works fine, however, if I attempt to replace a string ("= ") with another string ("="), it appears to get stuck in some endless loop somewhere.

I have left it running for hours, and it is still stuck at the same replace statement. Is there something I'm missing?

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Mazdak31-May-02 2:34

Mazdak

31-May-02 2:34

Whats your code?

Mazy

"The more I search, the more my need
For you,
The more I bless, the more I bleed
For you."The Outlaw Torn-Metallica

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Munkijo31-May-02 7:27

Munkijo

31-May-02 7:27

It's not a very elegant method, but the code is:

void CParser::StandardiseHTML ( CString* HTMLfile )
{
HTMLfile->Replace ("@", "@");
HTMLfile->Replace ('\n', ' ');
HTMLfile->Replace ('\t', ' ');
HTMLfile->Replace (" ", " ");

while ( HTMLfile->Replace (" ", " ") != 0 );

HTMLfile->Replace (" =", "=");
HTMLfile->Replace ("= ", "=");
HTMLfile->MakeUpper ();
}

It manages to get into trouble with the statement

HTMLfile->Replace (" ", " ");

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Munkijo31-May-02 7:33

Munkijo

31-May-02 7:33

What??? No, where it says

HTMLfile->Replace (" ", " ");

the first string is actually a non-braking space character - In the while loop, it's meant to have two spaces between the first seyt of inverted commas, and one in the second set.

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Bill Wilson31-May-02 14:22

Bill Wilson

31-May-02 14:22

Is it possible the first character is actually a space just like the second? That would cause an infinite loop, as each call to replace will find the same character and replace it with itself.

To Release or Not to Release...

Braulio Dez31-May-02 0:59

Braulio Dez

31-May-02 0:59

Hi,

Sometimes, I feel a little bit lost with COM, and QI AddRef Release, smart pointers, long pointers to...., just two case:

Should I Release this pointer or not ?

LPDISPATCH pDisp = Fmt.GetObject(); // Fmt is from Ms Word WD::OLEFormat Fmt

And in this case ?

BSREPORTCTRLSLib::IBsMetafile *pIBsMeta;
pDisp->QueryInterface(IID_IBsMetafile, (void **) &pIBsMeta);

Thanks, Greetings
Braulio

Tomasz Sowinski31-May-02 1:21

Tomasz Sowinski

31-May-02 1:21

[edited - I shouldn't watch FIFA World Cup and answer questions at the same time]
You should use Release when you're done with interface returned from QueryInterface call.

Have no idea about GetObject.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Len Holgate31-May-02 1:21

Len Holgate

31-May-02 1:21

QI calls AddRef() on your behalf internally, calling it again on the returned pointer means you now have 2 references on the interface pointer and need to call Release() twice...

See: ATLBase.h 5374 (your line numbers may vary Wink | ;)

) for an example QI implementation:

ATLINLINE ATLAPI AtlInternalQueryInterface(
   void* pThis,
   const _ATL_INTMAP_ENTRY* pEntries, 
   REFIID iid, 
   void** ppvObject)
{
   ATLASSERT(pThis != NULL);
   // First entry in the com map should be a simple map entry
   ATLASSERT(pEntries->pFunc == _ATL_SIMPLEMAPENTRY);
   if (ppvObject == NULL)
      return E_POINTER;
   *ppvObject = NULL;
   if (InlineIsEqualUnknown(iid)) // use first interface
   {
      IUnknown* pUnk = (IUnknown*)((int)pThis+pEntries->dw);
      pUnk->AddRef();
      *ppvObject = pUnk;
      return S_OK;
   }
...

Len Holgate
www.jetbyte.com
The right code, right now.

Tomasz Sowinski31-May-02 2:29

Tomasz Sowinski

31-May-02 2:29

This happens when you watch a game and surf CP. Anyway, Senegal leads 1 Blush | :O

after first half Wink | ;)

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Len Holgate31-May-02 2:28

Len Holgate

31-May-02 2:28

Len Holgate
www.jetbyte.com
The right code, right now.

Len Holgate31-May-02 1:16

Len Holgate

31-May-02 1:16

Braulio Díez wrote:
Should I Release this pointer or not ?

LPDISPATCH pDisp = Fmt.GetObject(); // Fmt is from Ms Word WD::OLEFormat Fmt

Yes. A function has returned you an interface, it will have called AddRef() before it returned it to you, you now own a reference to the interface and should call Release() when you're done with it.

Braulio Díez wrote:
And in this case ?

BSREPORTCTRLSLib::IBsMetafile *pIBsMeta; pDisp->QueryInterface(IID_IBsMetafile, (void **) &pIBsMeta);

Again, yes. You've called QI, that results in the interface that is returned to you being AddRef()'d, you now own a reference to the interface and should call Release().

In both cases you have bare interface pointers so you're responsible for managing the reference counts. Generally, if you have bare pointers and a function returns you an interface you need to call Release() when you're done.

Len Holgate
www.jetbyte.com
The right code, right now.