Microsoft Statement on the Issue of Undocumented APIs

Redmond, Wash.-- September 1, 1992 -- (Business Wire)--A computer trade publication, InfoWorld, this week published an article on Microsoft Corp.'s use of ``undocumented'' APIs (Applications Programming Interfaces) in its applications for the Microsoft* Windows* operating system, raising the issue of whether or not this constituted an unfair advantage over its competitors.

Microsoft does not think that its applications developers have any unfair advantage over other applications developers because of the use of undocumented APIs. There are undocumented APIs in every major operating system in the world, and applications developers routinely make use of them.

Most major applications for Windows, including those being shipped today by Microsoft's principal competitors, make use of undocumented APIs in Windows.

Of the handful of such APIs used by Microsoft applications, almost all are artifacts of earlier versions of Windows. They are either obsolete under Windows 3.1 or add no meaningful functionality to the product.

``Our policy for applications is not to use undocumented APIs,'' said Mike Maples, executive vice president of products at Microsoft. ``I'm frankly surprised that we weren't able to reach that goal. However, Microsoft is not alone in its use of some undocumented APIs in its applications, and we derive no competitive advantage from using them.

``There are similar uses of undocumented calls by Borland, by Lotus, by WordPerfect, and by probably most other publishers of applications for Windows. No one is going to get any kind of advantage from such usage.''

Documented, Undocumented APIs Defined

The subject of documented and undocumented APIs is a fairly arcane one having to do with how developers call on resources from the operating system and how a systems publisher intends to support those resources in the future. Applications software developers use, or ``make calls to,'' APIs when they need the operating system to perform some function * for example, to display or move an object on the computer screen.

Documented APIs are those the operating system publisher expects to support over the long term; developers use these APIs to assure maximum compatibility with future releases of the operating system.

Undocumented APIs are ones the system publisher does not expect to support, because they involve trivial or obsolete functions; or they duplicate documented functions; or they are reserved for internal use by the operating system and are subject to change.

Other applications software developers are aware of undocumented APIs in Windows, which can be found by commonly used programming tools, and Microsoft has provided at least 26 other companies with detailed information on them. Microsoft is aware of at least thirty other major applications developers that have shipped products using undocumented APIs in Windows.

Microsoft works closely with other applications developers in a number of programs to provide them with technical information on APIs related to Windows 3.1, Windows NT*, and other systems software, including technologies and APIs that are still under development.

These programs include Open Process, which involves other companies in design reviews of APIs, and Open Tools, which involves the sharing of code and tools with other companies.

Information on Windows APIs is published in book and electronic form, in Software Development Kits and Device Driver Kits, through the Microsoft Development Network support program, and on several public electronic bulletin boards. The company regularly puts on developer conferences where system functions and APIs are explained in depth.

Because of the complexity of the issue, Microsoft has prepared a lengthy Question and Answer that is available to the press. The company is also preparing a detailed Technical Note that will describe all uses of all undocumented calls in its applications. This will be available to the press and developers by mid-week.

Founded in 1975, Microsoft (NASDAQ:MSFT) is the worldwide leader in software for personal computers. The company offers a wide range of products and services for business and personal use, each designed with the mission of making it easier and more enjoyable for people to take advantage of the full power of personal computing every day.

Note to Editors: Microsoft is a registered trademark and Windows and Windows NT are trademarks of Microsoft Corp.

CONTACT: Microsoft Corp., Redmond Collins Hemingway, 206/882-8080 01:53 ET AUG 31, 1992

Copyright (c) 1992, Business Wire