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Browse Prior Art Database

Interprocess Communication using Presentation Window Parameters

IP.com Disclosure Number: IPCOM000114658D
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Anderson, BJ: AUTHOR [+3]

Abstract

Disclosed is a process that allows multiple Operating System/2* (OS/2) programs to communicate with each other without using pipes, shared memory, or semaphores. This process is known as Interprocess Communication using Presentation Window Parameters (ICPWP).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Interprocess Communication using Presentation Window Parameters

      Disclosed is a process that allows multiple Operating System/2*
(OS/2) programs to communicate with each other without using pipes,
shared memory, or semaphores.  This process is known as Interprocess
Communication using Presentation Window Parameters (ICPWP).

      Currently, OS/2 programs can communicate using OS/2 resources
such as pipes, shared memory, or semaphores.  These methods have
disadvantages which include resource release if all using programs
terminate.  These resources are freed by the operating system if the
using programs terminate.  This means that each time they are to be
used, there is the possibility that they will have to be created.
Another disadvantage is that there is a limited number of pipes and
shared memory segments available on OS/2.  There is a chance that
when these resources are required to communicate they may not be
available.  In addition to these problems, security is a concern.
Programs that deal with data that must be secure are exposed by using
shared memory and pipes.  The names of these resources can be easily
determined by examining the PSTAT buffer.  Global variables are
another way of communicating among programs but the problem with
these resources is they must be defined as static.  If a program
needing to communicate with another program is reentrant, then global
variables can't be used.

      To solve this problem, ICPWP was invented.  ICPWP uses the
capability of the OS/2 Presentation Manager* (PM) presentation
parameters to pass information among programs.  Each presentation
parameter used to communicate information among programs is attached
to individual PM windows using a value of greater than 2048 in the
identify field.  (Any presentation parameters with an ID value
exceeding 2048 are user defined and do not affect the presentation of
the window.)  The first appli...