[THIN] KB: CTX108614 - Time Zone Redirection and Legacy Applications
- From: "Jim Kenzig http://ThinHelp.com" <jkenzig@xxxxxxxxx>
- To: thin@xxxxxxxxxxxxx
- Date: Fri, 20 Jan 2006 10:23:57 -0800 (PST)
CTX108614 - Time Zone Redirection and Legacy Applications
This document was published at: http://support.citrix.com/article/CTX108614
Document ID: CTX108614, Created on: Jan 18, 2006, Updated: Jan 19, 2006
Products: Citrix Presentation Server 4.0 for Microsoft Windows 2003, Citrix
Presentation Server 4.0 for Microsoft Windows 2000, Citrix MetaFrame XP 1.0 for
Microsoft Windows 2003, Citrix MetaFrame XP 1.0 for Microsoft Windows 2000,
Citrix MetaFrame Presentation Server 3.0 for Microsoft Windows 2003, Citrix
MetaFrame Presentation Server 3.0 for Microsoft Windows 2000
Symptoms
The Time Zone Redirection feature in MetaFrame XP 1.0, MetaFrame Presentation
Server 3.0, and Citrix Presentation Server 4.0 may not work for certain
applications that do not load User32.dll.
Cause
The current implementation of the MetaFrame Time Zone redirection feature is
based on Microsoft?s Windows Hooking capabilities. In an ICA session, certain
calls made by an application process to the Windows operating system to
retrieve Time and Time Zone information are intercepted and answered by the
MetaFrame server?s Time Zone components.
In order for these components to work, an application must load the Windows
User32.dll file.
This DLL must be loaded, in order to enumerate the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
One of the values in this registry key is: AppInit_DLLs
This value needs to be read in order to load the core MetaFrame hooking file,
mfaphook.dll, into the process space of an application process. This then
allows other components to be loaded that provide MetaFrame specific
functionality, such as Time Zone Redirection.
For more information on mfaphook.dll, refer to
CTX107824 ? Citrix API Hooks (mfaphook.dll) Explained and Enumerated.
Resolution
The following suggestion is more applicable to programs that are not GUI
based, written in C/C++, and probably written some time ago. Whereas most GUI
based applications will automatically load User32.dll.
Since the challenge is to get the application process to load User32.dll, an
easy way would be to call one of the Exported functions of this DLL ? for
example GetTopWindow(NULL);
Another method would be to actually use the Windows API LoadLibraryEx(), and
load the DLL.
More Information
CTX303498 ? Troubleshooting Client Time Zone Issues In MetaFrame XP.
Jim Kenzig
CEO The Kenzig Group
http://www.kenzig.com
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