WIN32 API and Windows CE

The Win32 API is the core programming interface for Windows CE. In the early 1990s, Microsoft announced that its two core strategic technologies were Win32 and the Component Object Model (COM). The Win32 API is supported on all Windows operating systems, including 16-bit systems (Microsoft Windows 95, Windows 98, and Windows Millennium Edition) and 32-bit systems (Microsoft Windows NT, Windows 2000, and Windows XP). Windows CE was the first Microsoft operating system to use the Win32 API for both device drivers and applications. Sixteen-bit Windows systems use the Virtual (VxD) drivers at their lowest layer, and 32-bit Windows systems have a proprietary kernel-mode API that is decidedly not Win32. Therefore, Windows CE is more deeply connected to Win32 than any other Microsoft operating system. Win32 has been referred to as the "assembly language of Windows," because it is a very low-level API with very primitive functions. Just as multiple machine language instructions are needed to accomplish even the simplest task, multiple Win32 function calls are often needed to do real work. This is, however, the API that all other APIs and development tools ultimately rely on to get things done. In the context of the .NET Framework, Win32 code is referred to as "unmanaged code." This is because the Common Language Runtime does not manage the memory, or guarantee the security and type-safety, of Win32 code. .NET code, by contrast, is called "managed code" because all these features and more are provided by the .NET runtime. Understanding the distinction between managed and unmanaged code is key to understanding the difference between these two APIs.