CODEWITHSUNDEEP
winapi
TownCube
TownCube

Reputation: 1310

Risks of using KEY_WOW64_64KEY on a 32bit application

We currently have a 32bit application that requires various key/value pairs to be loaded from the registry before use.

Previously we had completed this by loading the .reg as part of the installation. Running it on 64-bit Windows the .reg components end up in the 64-bit store, but our 32-bit application looks in the 32-bit store.

I was thinking of using KEY_WOW64_64KEY to force our 32-bit application to always use the 64-bit store however this answer advises against that. Then I thought we could change the .reg file to point to the 32-bit store but the comment on this answer advises against assuming the key will always be called "Wow6432Node"

Is there any perferred way to do this (other than migrating the whole app to 64-bit)? What are risks of a 32-bit application using the 64-bit store?

Upvotes: 1

Views: 1245

Answers (1)

Anders
Anders

Reputation: 101666

As long as you don't pass the HKEY handle to non Reg* functions that expect x86==native registry I don't think there are any risks. (Filesystem redirection on the other hand is not per handle and can cause problems if a sub-function calls LoadLibrary or CoCreateInstance etc)

If using KEY_WOW64_64KEY seems like too much of a hack, why not have the (32 bit) installer write to the registry instead of using .reg files? The only downside by doing this is that if you create a x64 version of your app in the future it will not share the settings with the x86 version. (This might be a good thing or a bad thing)

Upvotes: 1

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