Windows Installer Editor Reference
65
Working With Wise Installation Files
Custom actions
Windows Installer Editor does not contain 64-bit versions of custom actions, however:
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When you create a custom action that calls a JScript or VBScript file, a check box
lets you indicate that the script needs to access 64-bit functionality and run in a 64-
bit process.
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The following Call Custom DLL actions can call 64-bit .DLLs:
Call Custom DLL From Destination
Call Custom DLL From Installation
Call Custom DLL From Installed Files
Because .DLLs are processor-specific, the .DLL that you call must target the same
platform (32-bit, x64, or 64-bit Itanium) as the installation. In a mixed-target
project file (.WSI), condition each Call Custom .DLL custom action for the
appropriate platform.
32-bit Applications on 64-bit Computers
WOW64 (Windows On Windows 64) is an emulator that lets 32-bit applications run on
64-bit versions of Windows. To prevent file and registry collisions, it isolates 32-bit
applications from 64-bit applications by:
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Redirecting 32-bit applications to the Program Files (x86) directory.
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Redirecting system calls from 32-bit applications to the SysWOW64 directory.
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Providing separate logical views of key portions of the registry, intercepting 32-bit
registry calls to each logical registry view, and mapping them to the corresponding
physical registry location. The reflection process is transparent to the application.
Therefore, a 32-bit application can access registry data as if it were running on 32-
bit Windows even if the data is stored in a different location on 64-bit Windows.
When an installation contains both 32-bit and 64-bit components, place files and
registry keys in the appropriate location for the platform they target.
Search for “Running 32-bit Applications” and “WOW64 Implementation Details” in the
MSDN Library (
msdn.microsoft.com/library/
).
Resource
Place 32-bit versions in
Place 64-bit versions in
Program files (default
directory)
Program Files (x86) directory
Program Files directory
Operating system components
and shared libraries
Windows\SysWOW64 directory
Windows\System32 directory
Registry keys
Do one of the following:
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Place the keys in the 32-
bit registry view. They will
be installed in the
WOW6432Node (for hives
that have a WOW6432
node).
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Do not mark the
component as 64-bit.
Do one of the following:
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Place the keys in the 62-bit registry view.
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Mark the component as 64-bit on the
Component Details dialog box.
