Browse Prior Art Database

Creating a Hidden Application Work Window to Enable Easy Window-Specific Que

IP.com Disclosure Number: IPCOM000113653D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 88K

Publishing Venue

IBM

Related People

Morgan, SA: AUTHOR [+2]

Abstract

In an OS/2* Presentation Manager* (PM) client-server application, situations can arise where window-specific information is required when there is not a specific application window available from which it can be queried. There are other situations where window characteristics need to be discovered before an application window can be set to use them.

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

Creating a Hidden Application Work Window to Enable Easy Window-Specific
Que

      In an OS/2* Presentation Manager* (PM) client-server
application, situations can arise where window-specific information
is required when there is not a specific application window available
from which it can be queried.  There are other situations where
window characteristics need to be discovered before an application
window can be set to use them.

      An example of the first is when an application is initializing
a secondary thread.  It requires certain information before any
windows have been created on that thread.  One thing it requires is
the handle of the application message queue that is being used.  If
the WinCreateMsgQueue API returns an error indicating that the
message queue already exists, the message queue must be queried in
another fashion.  It can be queried with the WinQueryWindowULong API,
passing the QWL_HMQ parameter, but this requires a window to which
the API can refer.

      An example of the second type of situation involves the
querying of the default font for an application.  Some font
information is best queried from a window in which that font is set,
using the GpiQueryFontMetrics API.  This API requires a presentation
space, which is again based on a specific window.

      Without an application window available to query this type of
information, some other technique needs to be devised.  This
disclosure describes a technique that enables an application to query
application-specific information that is tied to individual windows
in PM, without needing to have an application window created from
which to query it.

      The solution to this problem is to create an application work
window from which these types of queries can be made.  This work
window would be created at the beginning of the application and be
available thereafter for any window-specific queries necessary when a
real window of the application is not available.

      This work window should be created such that it is not visible
and does not add any performance penalties.  It should also be the
most simple window that can achieve the objectives.  These goals are
met by creating an entry field window that is a child of the desktop
object window.  Being descended f...