Ó Copyright 1992 Xerox Corporation. All rights reserved.

Abstract: Some Cedar applications accept input in the form of commands that are placed on a queue. A first application, A, can drive a second one, B, by putting commands on B's input queue. This works fine if A just wants B to do something. However, sometimes A may wish B to return a value. This (very simple) package provides a data structure that can be placed on a queue to request that a value be returned, and a mechanism to block the caller until the value is available. This package has been used in Gargoyle. This release will allow other packages to use it as a standard.

FutureValues is the right choice when a consumer thread must wait for a producer thread to produce a value. In situations where any of several threads can produce the value, LazyEvaluation.df is an alternative.

Created by: Eric A. Bier

Maintained by: Eric A. Bier <Bier:PARC>

Keywords: future values, input queues, input languages, returned values, blocking