WINDOWS PROGRAMMING

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WINDOWS PROGRAMMING

• Where
• the fun
• starts

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WINDOWS 98 (Win32) PROGRAMMING

• FROM THE GROUND UP
• With Application Programming Interface (API) and
  C

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Key Features of Windows 98

• 1. The 32-bit programming environment
• 2. Thread-based multitasking
• 3. The call-based interface
• 4. Dynamic Link Libraries

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32-bit Operating System

• Windows 3.1 - 16 bit
• Windows NT, 95, 98 - 32 bit

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Thread-Based Multitasking

• Multitasking operating system
• Share CPU
• process-based multitasking
• thread-based multitasking
• A thread is an individual unit of executable code
  within a process.

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Call-Based Interface (API)

• The call-based interface is an extensive set of
  system-defined functions that provide access to
  operating system features.
• Collectively these functions are called
  Application Programming Interface (API).

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Dynamic Link Libraries (DLLs)

• The Win32 API functions are contained in Dynamic
  Link Libraries (DLLs).
• Dynamic Linking provides
• 1. Disk space from being wasted
• 2. Update link library routines
• 3. No recompilation required

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Two Ways to Program for Window 98

• 1. Use the API functions defined by Win32. In
  this approach, your programs directly utilize the
  API and explicitly handle all of the details
  associated with a Windows 98 program.

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WINDOWS PROGRAMMING LANGUAGES

• C C
• BASIC VISUAL BASIC

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C Windows Programming

• 2. The second way to program for Windows 98 uses
  a special C class library, which encapsulate
  the API. By far the most popular Windows
  programming class library is MFC (Microsoft
  Foundation Classes).
• It is best employed after you have gained a firm
  foundation in Windows programming using API!

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WinMain( )

• Function must perform the following
• 1. Define a window class
• 2. Register that class with Win98
• 3. Create a window of that class.
• 4. Display the window
• 5. Begin running the message loop.

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Windows Data Types

• HANDLE is a value that identifies some resources
• HWND is a 32-bit integer that is used as a window
  handle
• UINT is an unsigned 32-bit integer
• BYTE is an 8-bit unsigned character
• WORD is a 16-bit unsigned short integer
• DWORD is an unsigned long integer

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Windows Data Types

• LPSTR is a pointer to a string
• LPCSTR is a const pointer to a string
• LONG is another name for long
• BOOL is an integer

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Code Online

• Please refer to the following web site for code
  examples
• http//www.osborne.com

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WINDOWS MESSAGES

• WM_COMMAND - Sent as the result of a mouse click
  or key press.
• Carries as part of its structure, IDs of Menu
  Items, Buttons or Dialog Box Controls selected by
  the mouse or keyboard.
• Other messages can be sent to a window or dialog
  box by a call to a function inside the program
  telling the object to behave a certain way.

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FLAGS

• Determine Window Style or Behavior
• Can Be Grouped in a Single Call to a Creation
  Function in Order to Add Functionality to a
  Window
• hWnd CreateWindow ( szAppName, / ClassName
  /
• My Window", / window title /
• WS_OVERLAPPEDWINDOW, / window style flag/
• 70, / horizontal position
  /
• 70, / vertical position
  /
• 500, / window width /
  etc...
• Flags are Names for an Underlying Number
  Created with define in windows.h

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New Data Types

• MSG
• BOOL
• HWND
• HANDLE
• WNDCLASS

• LRESULT
• WPARAM
• LPARAM
• CALLBACK
• UINT

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New Files

• include ltwindows.hgt
• Resource Files .rc
• Custom Header Files .h

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New Classes

• WNDCLASS
• structure declaration (data type) in windows.h
• contains members and pointers to functions for a
  basic window.

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Visual C

• Windows Programming

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Visual C

• Can call any Win 32 function
• Code generated by wizards

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Components of Visual C

• ATL Active Template Library
• MFC Microsoft Foundation Class Library
• WFC Windows Foundation Class Library

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Windows Programming

• It is more important to know C than it is to
  know the Win 32 Application Programming Interface
  API

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Win32 vs. Win16

• 32-bit programming for
• Microsoft Windows 95, 98, NT
• using Win32 API
• Compiled MFC programming interface will work on
  any of the above platforms

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Win 32 Programming Features

• COM Component Object Model
• DAO Data Access Objects
• ActiveX Controls
• OLE/DB database programming
• Dynamic HTML

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GDI - Graphic Device Interface

• Instead of addressing the hardware, the C
  program calls GDI functions that reference a data
  structure called a device context.

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Resource-Based Programming

• When you program for Windows, you store data in a
  resource file using a number of established
  formats.
• The linker combines this binary resource file
  with the C compilers output to generate an
  executable program.

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Resource Files

• Can include
• bitmaps, icons,
• menu definitions,
• dialog box layouts, strings
• and even user defined custom resource formats

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Components of Visual C

• ATL Active Template Library
• MFC Microsoft Foundation Class Library
• WFC Windows Foundation Class Library

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Memory Management

• Past memory problems with older versions of
  Windows
• locking memory handles
• thunks
• burgermasters

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Memory Management Win 32

• Virtual Memory
• Memory-Mapped Files

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DLL - Dynamic Link Libraries

• Multiple applications share DLLs
• Which saves memory and disk space
• You can create your own Extension DLLs which
  built on the
• MFC Microsoft Foundation Class Library.

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Visual C Files

• APS Supports resource view
• BSC Browser information file
• CLW Support class wizard
• DEP Dependency file
• DSP Project file

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Visual C Files

• DSW Workspace file
• MAK External make file
• NCB Support Class View
• OPT Holds workspace configuration
• PLG Builds log file

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Windows Programming Options in C

• Program in C with the Win32 API
• Write your own C Windows class library that
  uses Win32
• Use the MFC application framework
• Use another Windows-based application framework
  such as Borlands Object Windows Library OWL

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WinMain Function

• Windows requires your application to have a
  WinMain function.

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Single Document Interface (SDI)

• SDI applications only have 1 window
• Windows Notepad is an example

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Multiple Document Interface (MDI)

• An MDI application has multiple child windows,
  each of which corresponds to an individual
  document.
• Microsoft Word is a good example.

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View - Users Standpoint

• A view is an ordinary window that the user can
  size, move and close in the same way as any other
  windows-based application window.

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View - Programmers Standpoint

• A view is a C object of a class derived from
  the MFC library Cview class.
• Like any C object, the view objects behavior
  is determined by the member functions (and data
  members) of the class.

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Building an Application

• 1. Run AppWizard to generate SDI application
  source code.
• 2. Compile and link the generated code.
• 3. Test the resulting application.
• 4. Browse the application.

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Resource File

• Although the applications resource script is an
  ASCII file, modifying it with a text editor is
  not a good idea.
• Thats the resource editors job.

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Resource File

• Accelerator
• Definitions for keys that simulate menu and
  toolbar selections
• Dialog
• Layout and content of dialog boxes
• Icon
• 16-by-16 and 32-by-32 pixels

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Resource File

• Menu
• The applications top-level menu and associated
  pop-up menus.
• String Table
• Strings that are not part of the C source code.

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Resource File

• Toolbar
• The row of buttons immediately below the menu.
• Version
• Program description, version number, language,
  and so on.

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Encapsulation

• Combining data and the functions that process the
  data into a single entity.
• Data refers to the members of a structure or
  CLASS that hold data.
• Functions refer to pointers to functions
  included as members of a structure or CLASS
• Window and Dialog Classes Provided by C are
  Actually Structures Set up this Way.

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Writing a Windows Program
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STEP BY STEP APPROACH
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STEP 1

• Initialize the Application . . .
• Write a function that does the following
• declare a variable of the WNDCLASS type
• fill the members of that variable with values
  that customize your window
• call the RegisterClass function, passing your
  class
• return TRUE or FALSE (BOOL) to the main function,
  based upon whether RegisterClass was successful
  or not

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BOOL InitApplication ( HANDLE hInstance )
WNDCLASS wc wc.style
CS_HREDRAW CS_VREDRAW wc.lpfnWndProc
MainWndProc wc.cbClsExtra
0 wc.cbWndExtra 0 wc.hInstance
hInstance wc.hIcon LoadIcon (
hInstance, IDI_APPLICATION ) wc.hCursor
LoadCursor ( NULL, IDC_ARROW
) wc.hbrBackground GetStockObject (
WHITE_BRUSH
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BOOL InitApplication ( HANDLE hInstance )

• wc.lpszMenuName NULL
• wc.lpszClassName szAppName
• if ( !RegisterClass ( wc ) )
• return ( FALSE )
• return ( TRUE )

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STEP 2

• Initialize an Instance of the Application
• Write a function to do the following
• Assign the current instance to a global variable
  for use by other windows and dialog boxes in the
  program.
• Call the CreateWindow function, passing the App
  Name as specified in your class, the windows
  position and size, handles to parent and child
  windows and the handle to the current instance.
• If the window could not be created, return FALSE,
  otherwise call the ShowWindow function to display
  the window.

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BOOL InitInstance ( HANDLE hInstance, int
nCmdShow )

• hInst hInstance / assign instance to
  global variable /
• hWnd CreateWindow ( szAppName, / ClassName
  /
• My Window", / window title /
• WS_OVERLAPPEDWINDOW, / window style flag/
• 70, / horizontal position
  /
• 70, / vertical position
  /
• 500, / window width /
• 350, / window height /
• NULL, / handle of parent
  window /
• NULL, / handle of child or
  menu /
• hInstance, / handle of app
  instance /
• NULL ) / window creation
  data /
• if ( !hWnd ) / If window could not be created,
  return "failure /
• return ( FALSE )
• ShowWindow ( hWnd, nCmdShow ) / Show the
  window /
• return ( TRUE ) / Returns the
  value from PostQuitMessage /

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BACK IN MAIN

• Make Calls to Your InitApplication and
  InitInstance Functions.
• Write a Windows Message Loop that Continuously
  Checks for New Messages (such as the click of a
  mouse button or press of a key on the keyboard)
• When a Message is Received, the WNDCLASS Window
  you Created will Call the Window Procedure it
  points to (MainWndProc).

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STEP 3

• Handle the Windows Messages Received
• Write MainWndProc, which does the following
• Use nested switch constructs to handle valid
  windows messages expected by the main window.
• Makes calls to other procedures such as Dialog
  Box procedures, when necessary for handling
  messages to other resources.

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LRESULT CALLBACK MainWndProc ( HWND hWnd,
UINT message,WPARAM wParam, LPARAM
lParam )

• switch ( message )
• case WM_COMMAND / Menu Selection or Dialog
  Box Control /
• switch (wParam)
• case CM_EXIT / ID of the EXIT
  menu item /
• DestroyWindow ( hWnd )
• case CM_MESSAGE_TO_SCREEN / another menu
  item /
• MessageBox( hWnd, "Message Text",
  Message Title", MB_OK)
• default
• return ( DefWindowProc ( hWnd, message,
  wParam, lParam ) )
• default
• return ( DefWindowProc ( hWnd, message, wParam,
  lParam ) )