Applications programming interface for Windows: a timely standard

m The Windows environment produced by Microsoft is arguably the most common programming environment in the world. It exists on millions of computers. Software designed for that environment represents a tremendous investment on the part of Microsoft and other software organizations. By standardizing on the Applications Programming Interface for Windows (APIW), this investment can be safeguarded for the future. This article describes APIW efforts and explains why the industry is behind them. icrosoft’s Windows is really a set of functions, libraries and other system elements that make up an interface between DOS and conforming applications. This set of functions is called the Windows Applications Programming Interface (API). For Windows, the API also helps software programs manage windows, menus, icons, and other graphical user-interface elements. Microsoft and other software developers have made a massive investment in the Windows API, of both dollars and time—so massive that it dwarfs almost all other commercial software development activities to date. Analysts have estimated that Microsoft to date has invested over $50 million in the Windows interface, and that it is selling over one million copies per month. There are no estimates of the investment made by other development organizations, but it is large. The investment is justified by the huge marketplace: Windows on Intel-based microprocessors is estimated to make up 80% of the desktop market. Windows currently supports a 16-bit interface (the “traditional” Windows function calls) and a 32-bit interface, Win32 (the Windows 95 and the Windows NT function calls). The two interfaces are not necessarily compatible with each other. Most existing Windows software deals with the 16-bit interface. The release of Windows 95 in August 1995 increased the number of Win32 programs in the marketplace.