msvcr90.dll dependency in VS 2005 C++ project

Question

I've created a DLL project in VS 2005 for native Win32/unmanaged C++, call it myProj.dll. It depends on a 3rd-party commercial DLL that in turn depends on msvcr90.dll (I assume it was built from a VS 2008 project). I'll call it thirdParty.dll.

My DLL project builds just fine in VS2005. I've built a test app (again, VS 2005 Win32 C++) that links to myProj.lib. (As an aside, judging by the small size of the .lib, and by the fact that, at run-time, the app must locate myProj.dll, I'm guessing that the .lib is just a wrapper for a call to loadLibrary() that loads the actual DLL; is that close?)

My problem is that, at run-time, the test app cannot locate msvcr90.dll (nor msvcp90.dll), the dependency on which stems from the thirdParty.dll.

I've installed Microsoft's redist package, and so have all the std (9.0) C++ libraries in c:\WINDOWS\WinSxS\x86_Microsoft.VC90.CRT_... . What's more, if I point the dependency walker at thirdParty.dll, it happily resolves the references to that location.

But, if I point depends.exe at my test app (.exe) or myProj.dll, msvcr90.dll and msvcp90.dll are not found.

I'm guessing there's something I need to configure in VS2005 so that the .exe or myProj.dll are aware of the location of the 9.0 versions of the std C++ libraries (presumably where the redist package installed them in C:\WINDOWS\WinSxS), but I can't seem to figure out what it is. Am I on the right track?

I note that, if I simply copy the msvc*90.dll files to my app directory, then the dependency is resolved, but I get the run-time error about improper loading of std c++ DLLs, etc.

Thanks immensely in advance.

jussij jussij · Accepted Answer · 2008-12-01T23:04:17

This looks like a "Side-by-Side Assemblies" issue to me.

From what I can tell, Microsoft in an attempt to stop the DLL Hell problems of past years has introduced a concept of "Side-by-Side Assemblies".

In a nut shell it means that your application needs to tell Windows which version of the CRT it was designed to work with. When the application is installed Windows will make sure you application gets its own private copy of these DLL files.

To make it all work you need to embed the application's DLL dependencies into the applications Manifest file and attaching it to the project using the Manifest Tool, Input and Output section of the application project settings.

As an example here is the manifest I use for the Zeus for Windows IDE:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
  <assemblyIdentity
      name="Xidicone.Windows.Zeus for Windows"
      version="3.9.6.69"
      processorArchitecture="X86"
      type="win32" />

  <description>Zeus for Windows</description>

  <dependency>
    <dependentAssembly>
      <assemblyIdentity
            type="win32"
            name="Microsoft.VC80.CRT"
            version="8.0.50608.0"
            processorArchitecture="x86"
            publicKeyToken="1fc8b3b9a1e18e3b" />
    </dependentAssembly>
  </dependency>

  <dependency>
    <dependentAssembly>
      <assemblyIdentity
          type="win32"
          name="Microsoft.Windows.Common-Controls"
          version="6.0.0.0"
          processorArchitecture="X86"
          publicKeyToken="6595b64144ccf1df"
          language="*" />
    </dependentAssembly>
  </dependency>
</assembly>

Finally, if you plan to make an installer you will need to add the same versions of these DLL files to the application installer or alternatively have your installer run the Microsoft CRT redistributable installer.

FWIW I only found out about this when a user reported that Zeus no longer ran on Windows XP because of a missing MSVCRT runtime DLL file, yet Zeus had been working fine for over 10 years without ever once having to ship with a MSVCRT runtime DLL file.

msvcr90.dll dependency in VS 2005 C++ project

4 Answers