| Windows API | |
|---|---|
 The Win32 subsystem shown next to the POSIX and OS/2 subsystem in the architecture of Windows NT (Later Win64 is also available.) | |
| Developer | Microsoft |
| Release | November 20, 1985;40 years ago (1985-11-20) |
| Operating system | Microsoft Windows, OS/2 |
| Predecessor | DOS API |
| Type | API |
| License | Proprietary |
| Website | learn.microsoft.com/windows/apps/ |
The Windows API, informally WinAPI, is the foundational application programming interface (API) that allows a computer program to access the features of the Microsoft Windows operating system in which the program is running. Programs typically access this API using system libraries, which are shared libraries.
Each major version of the Windows API has a distinct name that identifies a compatibility aspect of that version. For example, Win32 is the major version of Windows API that runs on 32-bit systems. The name, Windows API, collectively refers to all versions of this capability of Windows.
Microsoft provides developer support via a software development kit, Microsoft Windows SDK, which includes documentation and tools for building software based on the Windows API.
- ↑ Both Pascal and x86 assembly were heavily used in earlier versions, before C became dominant. A reminiscence of this is that the API functions still use the Pascal calling convention to restore the stack from pushed parameters after a call (although they expect parameters pushed from right to left, as most C compilers do, by default).
- ↑ Nomenclature of released 64-bit versions includes Windows XP Professional x64 Edition and x64 Editions of Windows Server 2003, Windows Vista and Windows Server 2008 on the x86-64 (AMD64) platform, and Windows 2000 Server Limited Edition, Windows XP 64-bit Edition, Windows Advanced Server 2003 for Itanium and Windows 2008 Advanced Server for Itanium on the IA-64 platform.