Overview of the Win32 API

The Microsoft® Win32® application programming interface (API) allows applications to exploit the power of the 32-bit Windows family of operating systems. Using the Win32 API, you can develop applications that run successfully on all 32-bit versions of Windows while taking advantage of the features and capabilities unique to each version.

Differences in the implementation of the programming elements depend on the capabilities of the underlying features of the platform. The most notable difference is that some functions are supported only on the more powerful platforms. For example, service functions are available only on Windows NT®/Windows® 2000. Some functions have options that are supported on a subset of platforms. For example, PeekMessage supports additional flags on Windows 98 and Windows 2000. Most other differences are due to system limitations, such as restrictions on the range of values or the number of items a given function can manage. For example, there is a size limit on the cbString parameter of the TextOut function on Windows 95/98.

For general information about system limitations in Windows 95/98, see Windows 95/98 Limitations.

The Win32 API consists of the following functional categories:

• Base Services
• Common Control Library
• Graphics Device Interface
• Network Services
• User Interface
• Windows NT Access Control
• Windows Shell
• Windows System Information