Microsoft Assembly configuration for 32-bit mixed C/C++ application

Question

We have a 32 bit mixed C/C++ application that we are trying to deploy to the world. It naturally uses C and C++ runtime DLLs. We are using VS 2005.

The manifest constructed by VS2005 is the following:

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
   <dependency>
     <dependentAssembly>
       <assemblyIdentity type="win32" name="Microsoft.VC80.CRT" version="8.0.50727.42" processorArchitecture="x86" publicKeyToken="1fc8b3b9a1e18e3b"></assemblyIdentity>
     </dependentAssembly>
   </dependency>
 </assembly>

We ship this as a file in the same directory as the "application", named (changed to protect the innocent) "application.exe.manifest".

On the face of it, it is sort of reasonable. But, in installing on some systems, we get the message when "application.exe" is launched:

This application has failed to start because the application configuration is incorrect

One way to cure this is to run VCRedist_x86.exe from MSDN. (Unfortunately, while we can run it, we don't know exactly what it is doing. It appears to be parking DLLs in the SxS directories. But what else does it do?)

a) The MS docs seem to indicate that the assembly must have an assemblyIdentity tag directly underneath the assembly tag, that names the application itself. This is clearly missing here, but the manifest seems to partially work in that if we remove it, the application doesn't start even if the DLLs are present.

b) Remarkably the assembly doesn't mention the C runtime DLL. Do I need to just add that by hand?

c) We dont want to be dependent on whether the right version DLL is present on the target machine. Assuming that the assembly makes it clear which DLLs to use, how is that we can ensure the DLLs we need are on the target system? (In particular, we don't want run VCRedist or ask our customer to do this). Before assemblies came along, we solved this problem by simply placing the C and C++ DLLs in the same directory as the application .exe file, and Windows would look there first to pick them up. Can we still ship the C and C++ DLLs in the same directory? I can't figure out from the MS docs I can find how the SxS finds the appropriate dependent assemblies.

Any help appreciated.

Nathan Howell Nathan Howell · Accepted Answer · 2009-11-09T06:46:07

a) The manifest xml validation clearly has some problems. Depending on the version of Windows this may or may not be an issue. Since so many applications don't correctly follow the schema (and because it was never properly enforced), I doubt it will ever be strict here.

b) The C runtime DLL is referenced in the Microsoft.VC80.CRT.manifest file, pulling it in to to the loader dependency graph. Providing you have a dependency on the manifest, you will also implicitly have a dependency on the DLL.

c) Per my earlier comment, the correct thing to do (aside from installing the latest redist system wide) is to put the CRT manifest and all three DLLs in your application directory. This is poorly documented under SxS: Private Assemblies and Installing Side-by-side Assemblies as Private Assemblies. The probe order is defined in Assembly Searching Sequence.

Generally a SxS binding failure will put an entry in the Application (for Vista+) or System Event Log (pre Vista) describing the error.

Activation context generation failed for "C:\TEMP\sxs\PEVerify.exe".Error in manifest or policy file "C:\TEMP\sxs\Microsoft.VC90.CRT.MANIFEST" on line 4.
Component identity found in manifest does not match the identity of the component requested.
Reference is Microsoft.VC90.CRT,processorArchitecture="x86",publicKeyToken="1fc8b3b9a18e3b",type="win32",version="9.0.21022.8".
Definition is Microsoft.VC90.CRT,processorArchitecture="x86",publicKeyToken="1fc8b3b9a1e18e3b",type="win32",version="9.0.30729.1".
Please use sxstrace.exe for detailed diagnosis.

You can use sxstrace.exe in (Vista+) to see what the loader is actually doing. Junfeng covers this in more detail in Diagnosing SideBySide failures.

To get a better understanding of what is happening at runtime (after the manifest has been parsed and dependencies located), enable "Show Loader Snaps" for your image file (just the filename and extension, do not enter a directory name, like so: "notepad.exe") using gflags.exe. Run your application under windbg (Visual Studio's debugger may also work) and look at the output. Make sure to disable loader snaps when you're done debugging since it will slow down the application even when no debugger is attached. Sample output looks like this:

2d6c:36b4 @ 1246428223 - LdrpHandleOneOldFormatImportDescriptor - INFO: DLL "C:\Program Files\Microsoft SDKs\Windows\v6.1\Bin\PEVerify.exe" imports "MSVCR90.dll"
2d6c:36b4 @ 1246428223 - LdrpMapDll - INFO: Mapping static redirected DLL "C:\Windows\WinSxS\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4148_none_5090ab56bcba71c2\MSVCR90.dll"
ModLoad: 4fbd0000 4fc73000   C:\Windows\WinSxS\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4148_none_5090ab56bcba71c2\MSVCR90.dll
2d6c:36b4 @ 1246428285 - LdrpMapDll - INFO: Mapped DLL "C:\Windows\WinSxS\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4148_none_5090ab56bcba71c2\MSVCR90.dll" at address 4FBD0000
2d6c:36b4 @ 1246428285 - LdrpHandleOneOldFormatImportDescriptor - INFO: DLL "C:\Windows\WinSxS\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4148_none_5090ab56bcba71c2\MSVCR90.dll" imports "KERNEL32.dll"

Microsoft Assembly configuration for 32-bit mixed C/C++ application

3 Answers