Runtime error (dll loading) with win32 applications on x64 system, while compiling 0K

Question

I originally designed a win32 application on win7 32bits, with VC9.0. I recently upgraded to win7 64 bits, and tried to build+execute the previous application.

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Answer 1

It appears you are loading a 64-bit DLL into a 32-bit process or vice versa. Here's how I would go about tracking down the offending DLL.

The first step is to run dumpbin.exe (use a VS command prompt to get it on the PATH) on the executable to ensure the architecture is what you expect: dumpbin.exe /headers foo.exe. In the file header output, you should see a "machine" value of "x86" or "x64". In the optional header output, you should see a magic of "PE32" (for x86) or "PE32+" (for x64).

The next step is to run the appropriate dependency walker, available at www.dependencywalker.com, depending on the architecture (x86 or x64) of the executable. This tool should tell you if it locates a dependency on the search paths that is not of the same architecture.

If dependency walker finds a problem, the fix would then be to replace the offending library with a library of the same architecture or ensure the correct library is located before the incorrect library based on search paths.