This morning I was asked to enable the Windows XP visual styles for our application. No problem -- I've done that for applications many times. Just drop the appropriate manifest file in the right place, call InitCommonControls and all should be well. When I tried that this morning, though, I got an error message: "An application has made an attempt to load the C runtime library incorrectly. Please contact the application's support team for more information." I suspected our support team wasn't going to be much help on this one. The Visual C++ 2005 runtime library configuration strikes again.

Previous versions of Visual Studio and Visual C++ let you install the runtime libraries by simply copying them to a directory where your application could access them. The version 8 runtime libraries, however, must be installed in side-by-side mode, and your application must have a manifest that references the runtime libraries. MSDN has a Deployment Examples article that details this.

Because of this need, C++ projects in VS 2005 are already configured to include the appropriate manifest file that specifies dependencies on the exact versions of the runtime libraries. By dropping another manifest in the application directory (with a name like MyApp.exe.manifest) it overrode the manifest that was embedded within the binary itself. The overriding manifest only included the common controls library dependency, which caused the error mentioned above.

Embedding the manifest file as a resource in the binary seems preferable anyway (why install two files if one will do?), so there's fortunately an easy way to merge the common controls manifest with the auto-generated manifest. In the project properties, go into Configuration Properties > Manifest Tool > Input and Output and reference your manifest file in the Additional Manifest Files field:

Also, don't forget to call InitCommonControls in your application somewhere (preferably near the beginning!), which is declared in commctrl.h and defined in comctl32.lib, or all the manifest business will be in vain -- you'll still not get the XP style controls.

Here's a copy of a manifest file that is ready to use with any project:

XPCommonControls.manifest