Windows APIWindows API or Windows SDK is a set of APIs, (application programming interfaces) available in the Microsoft Windows series.
Win32 is the 32-bit API for modern versions of Microsoft Windows. The API consists of C functions implemented in dynamically linked libraries (DLLs), mainly in core DLLs: kernel.dll, user.dll and gdi.dll. Although Microsoft's implementation of the Windows API is copyright, it is generally accepted that other vendors can emulate Windows by providing an identical API, without breaching copyright.
The Windows API was originally designed to be object oriented, but computers at the time were limited in power and many new APIs and enhancements have been introduced, leading to the loss of some object-oriented aspects. In some ways it is a low-level interface, so many programmers prefer to use the MFC (Microsoft Foundation Classes) and other class libraries such as Borland's OWL (Object Windows Library) for a more high-level approach.
Among other things, the Windows API contains the graphical widget toolkit used in different Windows versions.
Among common API functions are: