MSDN Documentation

Overview

The Windows API (also known as WinAPI) is the core set of programming interfaces used to develop native Windows applications. It provides functions for:

• Creating and managing windows and controls
• Interacting with the file system
• Handling input devices
• Multithreading and synchronization
• Graphics and GDI/GDI+
• System services and security

Getting Started

To start using the Windows API in a C/C++ project:

1. Install Visual Studio (Community edition works fine).
2. Create a new Windows Desktop Application project.
3. Include windows.h in your source files.
4. Link against User32.lib, Kernel32.lib, etc., which Visual Studio does automatically for a Windows subsystem target.

Hello World Example

The classic minimal Windows application that creates a window and displays "Hello, World!" in its client area.

#include <windows.h>

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
        case WM_PAINT: {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hwnd, &ps);
            TextOutA(hdc, 10, 10, "Hello, World!", 13);
            EndPaint(hwnd, &ps);
            return 0;
        }
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
    }
    return DefWindowProc(hwnd, msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nShowCmd) {
    const char CLASS_NAME[] = "SampleWindowClass";

    WNDCLASS wc = {0};
    wc.lpfnWndProc   = WndProc;
    wc.hInstance     = hInst;
    wc.lpszClassName = CLASS_NAME;
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    RegisterClass(&wc);

    HWND hwnd = CreateWindowEx(
        0,
        CLASS_NAME,
        "Hello World - WinAPI",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 400, 300,
        NULL, NULL, hInst, NULL
    );

    if (hwnd == NULL) return 0;

    ShowWindow(hwnd, nShowCmd);
    UpdateWindow(hwnd);

    MSG msg = {0};
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}

Common Structures

Further Reading

• Official Win32 API Reference
• Getting Started with Win32
• Windows Driver Samples