Browse Prior Art Database

Virtual Windows in OS/2 Presentation Manager

IP.com Disclosure Number: IPCOM000100229D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Strope, GC: AUTHOR [+2]

Abstract

In standard Presentation Manager* (PM) applications, the programmer writes source code in things called "window procedures".

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Virtual Windows in OS/2 Presentation Manager

       In standard Presentation Manager* (PM) applications, the
programmer writes source code in things called "window procedures".

      The programmer uses a window procedure in a PM application by
doing the following:
1)   Registers the window procedure as a "class" with PM.
2)   Asks PM to create a "new window" of that class.
3)   PM responds with a "handle" to the new window; a window's handle
is like its telephone number.
4)   The programmer sends messages to the window when he wants
functions from the window procedure.  The programmer sends messages
via the window's telephone number.

      A typical PM application requires a large number of windows.
For example, a spreadsheet application would use a window for each
cell.  Unfortunately, the number of phone numbers Presentation
Manager can assign is limited to 1200, far short of the number needed
in a spreadsheet application.

      The technique described in this article allows programmers to
build applications that overcome PM's 1200 window limit by permitting
applications to use a virtually unlimited number of windows.

      We have invented two states for a window; they are the "window"
state and the "call" state.  A window is in window state when PM has
assigned it a phone number.  The programmer can swap a window from
window state to call state.  Doing this releases the window's phone
number back to PM.

      The programmer ke...