Introduction to Win32 API. An essential element to understanding Windows internals. Learning the API enables to write better code on Windows. Understanding of API is also important for Windows crash dump analysis and finding security vulnerabilities. Youtube - https://youtu.be/sg_0NolxkGc Windows API Index(MSDN) - https://msdn.microsoft.com/en-us/library/vs/alm/ff818516(v=vs.85).aspx#system_services

1. CREATING AWINDOW
Sangram Kesari Ray <Shankar.ray030@gmail.com>

2. ARCHITECTURE
• MessageBox provides very limited functionality
• We’ve to create our own windows – title bar, menu, toolbar,
scrollbar
• A dialog box is also a window with/without a title bar
• These are also windows(child windows) – push buttons,
radio buttons, check boxes, list boxes, scroll bars, text-entry
fields.
• A window receives the user input in the form of messages. A
window also uses messages to interact with other windows.

4. LETS SEE A DEMO
https://github.com/shankar-ray/Win32-
API/tree/master/Creating%20a%20Window

5. CODE REVIEW
1. Defined WNDCLASS structure
2. Initialize the fields of the structure // pointer to WndProc
(Windows/OS passes messages to WndProc), window class name
3. call RegisterClass method // register the class with Windows/OS, so
it can send messages to your Window(Application)
4. If no errors above call CreateWindow method // allocates memory
5. call showWindow method // put the window for display
6. call UpdateWindow method // send WM_PAINT message to WndProc
7. From now on, look for any event and retrieve them using message
loops and WindProc takes the charge

6. THEWNDPROC
1. WndProc is the heart and soul of a windows program
2. Nobody talks to it directly, only Windows/OS does
3. Even if a window has to talk to WndProc, it’ll call SendMessage
function and OS will talk to WndProc
4. Any event that occurs, like clicks, etc., Windows/OS sends
specific messages to WndProc, to do something with it.
5. Windows programming is all event based, even dragging the
application window towards left/right is an event.
6. Console applications don’t have this architecture