Normally, the focus is set to a control which was higher in z-order. But we can set focus in two ways.

1. Call SetFocus() function to desired control in OnInitDialog and return FALSE.
2. Call ::PostMessage( this->m_hWnd, WM_NEXTDLGCTL, (WPARAM)( GetDlgItem( IDC_BUTTON1 )->m_hWnd ), TRUE );  in OnInitDialog() and return TRUE. Don’t call SendMessage instead of PostMessage.
   

Method to generate assembly code
1. Take “Project settings” by Alt+F7
2. Go to “C/C++” tab.
3. Select “Listing Files” from Category combo box.
4. Select “Assembly with source Code” form Listing file type combo box.
5. Recompile the project.
6. Take the debug or release directory, you can see asm files

This can be done in another way, Just add /FAs to the “Project Options” edit box in the “C/C++” tab.

UNICODE is used by windows headers and _UNICODE is used by C-Runtime/MFC headers.

int DrawText( const CString& str, LPRECT lpRect, UINT nFormat );

We dont know the width and height of the rectangle where the text to display, so that the lpRect is empty
Then how calculate the text area ?

It is simple,

Eg:

CRect rcText( 0, 0, 0 ,0 );

dc.DrawText( csText, &rcText, DT_CALCRECT );
dc.DrawText( csText, &rcText, DT_CENTER );

The first DrawText fills rcText with required value, ie the hight of the text, width of the text.
Call next DrawText, then the text will display.

The return of the DrawText is the height of the text. But we also have to calculate the width of the text. So the above method is easy to use.

::ExtractIconEx( szProcessName, 0, &hSmallIcon, &hLargeIcon, 1 ) ;

You must destroy all icons extracted by ExtractIconEx by calling the DestroyIcon function.

int m_Data;

void Disp( int n)
{
int i = n + 100;
cout << “Data = ” << i;
}
};

int main()
{
Test* t = 0;
t->Disp( 100 );
}

What is the output of this function? Will it crash?

This program outputs Data = 200 Why?
Normally we think program will crash if function call with a null pointer. But if you know the internal working of member function call, it will easy to catch my words.

As you all know, there is only one definition of member function in memory. All the instance of the class uses this memory.
t->Disp( 100 ) will replaced by compiler as Test::Disp( Test* this, int n ) ( Note that every non static member function will have “this” pointer to refer the calling object itself ).

Then this is null pointer and n is 100. Inside the Disp function we just manipulate data that don’t depends the class. So there is no chance for crash.

But if we call member data inside the Disp function, the scene will change, this->m_Data surely crash the program.

pWnd->ShowWindow( SW_SHOW ); this is exactly same as ::ShowWindow( pWnd->m_hWnd, SW_SHoW );

Kernal objects must be manipulated by HANDLES contains:
files, thread, memory,events,mutexes,semaphores,pipes,processes