How many of us have been writing a batch file and suddenly wished for, perhaps, a way to pause for a specified time? Or maybe a way to clear the screen and write a message in the center? Most of us probably have; that's what has given rise to some of the niftiest tools and utilities: batch enhancers, "delay" programs, and a host of others. No matter what language we're using, we'll eventually find something that we want to do that can't be done because all languages have limits. Although the Rexx language is no exception to this rule, Rexx does have a great way of dealing with its limits. Rexx is an extensible language that allows its users the ability to integrate new functions by way of its API. When you chance to meet a limitation of Rexx, you can create the function that you want and then use it as an extension to the language.
It's actually not quite so simple. This article examines just what it takes to extend the Rexx language by using either the IBM OS/2(1) Rexx API or the Quercus Systems Personal Rexx(2) for Microsoft Windows NT(3) API. I'll also describe some of the other features of the Rexx API and the things you can do with them.
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Bill Potvin
bill.potvin@network.com