Microsoft KB Archive/93230

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Windows APPC for 16 and 32-Bit Windows


The information in this article applies to:

  • Microsoft Windows Software Development Kit (SDK) 3.1


Windows APPC defines a standard and consistent API for the 16 and 32-bit versions of the Microsoft Windows graphical environment. It encompasses a set of Windows-specific extensions designed to allow the programmer to take advantage of the message-driven nature of the Windows graphical environment.


The following file is available for download from the Microsoft Software Library:


For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:

Q119591 How to Obtain Microsoft Support Files from Online Services

This API has been designed and specified to provide a standard to which application developers can program and network software vendors can conform. These API details constitute documentation for application software developers and a specification for network software vendors.

Network software that conforms to this Windows APPC specification will be considered "Windows APPC compliant." To be Windows APPC compliant, a vendor must implement 100 percent of this Windows APPC specification. Suppliers of such interfaces shall be referred to as "Windows APPC suppliers."

Applications that are capable of exploiting any Windows APPC implementation will be considered as having a "Windows APPC interface" and will be referred to as "Windows APPC applications."

The purpose of this document is to specify the Windows APPC interface. It is assumed that the reader has a basic understanding APPC concepts.

While this is one of the WinSNA APIs to be standardized for the Windows environment, it is beyond the scope of this document to deal with other SNA (Systems Network Architecture) APIs.

Microsoft Windows Graphical Environment and Windows-Specific Extensions

This API has been designed for ALL implementations and versions of the Windows environment from and including version 3.0. It thus provides for Windows APPC implementations and Windows APPC applications in both 16- and 32-bit operating environments.

Windows APPC makes provisions for multithreaded Windows-based processes. A process contains one or more threads of execution. In the Win16 non- multithreaded world, a task corresponds to a process with a single thread. All references to threads in this document refer to actual "threads" in multithreaded Windows environments. In non-multithreaded environments (such as version 3.0), use of the term thread refers to a Windows process.

The extensions to the Windows environment included in Windows APPC are provided for maximum programming compatibility between Windows 3.x and Windows NT and optimum application performance in both environments.

Additional query words: SNASpec

Keywords : kbfile kbnetwork kbsample kbAPI kbSDKPlatform kbOSWin310 kbGrpDSNet
Issue type :
Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310

Last Reviewed: November 12, 1999
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