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Allowing an Application Programming Interface to Function in a Windowing Environment

IP.com Disclosure Number: IPCOM000038832D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

King, SA: AUTHOR [+3]

Abstract

A method is described for enabling an Application Programming Interface (API) to function in a windowing environment. An API is an interface allowing a user-written application to communicate with another application. The link between the programs is established through an address stored in an interrupt vector pointing to the API interrupt handler. The windowing environment allows multiple application programs to run concurrently on the same IBM Personal Computer. The windowing environment protects application programs by assigning each application its own set of interrupt vectors. These vectors are a software copy of the hardware interrupt vectors.

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Allowing an Application Programming Interface to Function in a Windowing Environment

A method is described for enabling an Application Programming Interface (API) to function in a windowing environment. An API is an interface allowing a user- written application to communicate with another application. The link between the programs is established through an address stored in an interrupt vector pointing to the API interrupt handler. The windowing environment allows multiple application programs to run concurrently on the same IBM Personal Computer. The windowing environment protects application programs by assigning each application its own set of interrupt vectors. These vectors are a software copy of the hardware interrupt vectors. When the windowing environment switches to another application program, it saves the old hardware interrupt vectors with the old application and substitutes the new interrupt vectors stored for the new application. For an API to function in a windowing environment, the interrupt vector employed to store the address of the API interrupt handler needs to remain constant regardless of what application is active. A solution is to load the API before the windowing environment. This will allow the API interrupt vector to be set up before the window environment. The windowing environment treats the values of the interrupt vectors as system values and uses them as default values for every application. The API would be available to all applications. The problem with this approach is that the windowing environment provides multitasking capabilities to applications loaded after it is loaded. The API requires the multitasking capabilities of the windowing environment to function properly. A solution to the problem...