What is Win32 API

The WIndows API, informally WinAPI,is Microsoft's core set of application programming interfaces(API's) available in the Microsoft Windows
operating systems.It was formerly called the Win32 API;however,the name Windows API
more accurately reflects its roots in 16-bit Windows and its support on 64-bit Windows.Almost all
programs interact with the Windows API; a small number (such as programs started early in the windows startup process)
use the NATIVE API.

OVERVIEW
The functionality provided by the Windows API can be grouped into 8 categories.
1-Base Services
Provide access to the fundamental resources available to windows system.Including things like file systems,
devices,processes and threads and error handling.These function reside in kernel.exe krnl286.exe
or krnl386.exe files on 16-bit windows and kernel32.dll on 32-bit Windows.

2-Advanced Services
Provide access to the functionality additional to the kernel.Included are things like the
Windows Registry,shutdown/restart the system (or abort),start/stop/create a Windows Service
manage User accounts.These functions reside in advapi32.dll on 32-bit WIndows.

3-Graphics Device Interface
Provide functionality for outputting graphical content to monitors, printers and other output
devices.It reside in gdi.exe on 16-bit WIndows and gdi32.dll on 32-bit Windows
in user-mode.Kernel-mode GDI support is provide by win32k.sys which communicates directly with the
graphics driver.

4-User Interface
Provide the functionality to create and manage screen windows and most basic controls
such as buttons and scrollbars,receive mouse and keyboard input, and other functionality associated with the GUI
part of Windows.The functional unit resides in user.exe on 16-bit Windows and user32.dll on 32-bit Windows
Since Window Xp versions,the basic controls resides in comctl32.dll together with
common controls(Common Control Library).
5-Common Dialog Box Library
Provide applications the standard dialog boxes for opening and saving files,choosing
color and font etc.The library reside in a file commdlg.dll on 16-bit Windows
and comdlg32.dll on 32-bit Windows.It is grouped under User Interface Category of the API

6-Common Control Library
Gives Application to some advanced controls provided by the operating system.These includes
things like status bars,progress bars,toolbars and tabs. The library resides in a
in a dll file called commctrl.dll 0n 16-bit Windows and commctrl32.dll on 32-bit Windows.

7-Windows Shell
Component of the Windows API allows application to access the functionality provided by the
by the operating system shell, as we well change and enhance it.The component resides in
shell.dll on 16-bit Windows and shell32.dll on 32-bit Windows.The shell LightWeigth Utility
function are in shlwapi.dll.

8-Network Services
Give access to various networking capabilities of the operating system.Its sub-component include
NetBIOS,WinSock,NetDDE,RPC and many others..........
.........to be continue.