Deploying C++ library in Azure

Question

Dear all,

I'm developing a cloud project with a WebRole which calls a simple C++ Hello Wolrd program. This is running fine in my simulation environment, but when I deploy it to Azure, it does not work. According to the IntelliTrace logs, I got a System.IO.FileNotFoundException: Could not load file or assembly "HelloWorld.DLL" or one of its dependencies.

I think the Azure environment is missing some components that VS2010 uses to run this application, but I'm not sure which components might be or how to properly configure the project to be run in Azure. When I remove the reference to my Hello World project, the application runs in Azure with out any problems.

I appreciate your help!

Juan C.

Answer 1

Hi everyone,

I'm developing a cloud project with a WebRole which calls a simple C++ Hello Wolrd program. This is running fine in my simulation environment, but when I deploy it to Azure, it does not work. According to the IntelliTrace logs, I got a System.IO.FileNotFoundException: Could not load file or assembly "HelloWorld.DLL" or one of its dependencies.

I think the Azure environment is missing some components that VS2010 uses to run this application, but I'm not sure which components might be or how to properly configure the project to be run in Azure. When I remove the reference to my Hello World project, the application runs in Azure with out any problems.

I appreciate your help!

Juan C.

Answer 2

Is your C++ DLL compiled as 32 bit by any chance?

---

http://blog.voidnish.com

Answer 3

Hi Nishant, thanks for your reply.

The C++ project is being compiled for x64 platforms. I also use the parameter enableNativeCodeExecution="true" in the ServiceDefinition.csdef file. The reference from the WebRole to the C++ DLL has the attribute Copy Local = True as well.

Answer 4

Are you statically or dynamically linking to the CRT? I'm not sure what guarantees are made about various C++ runtime redists being installed on Azure tenants, so you may want to try statically linking the CRT (and MFC/ATL if you're using them).

Answer 5

I think I'm dinamically linking to the CRT, but I'm not actually sure how to do that. I'm interested in trying static linking to CRT, so could you please give me more details or links that explain how to do that?

Answer 6

http://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx

Answer 7

My C++ DLL is a managed wrapper for unmanaged code, so, I'm using /clr.
When I use the /MT compiler option to statically link the CRT, the compiler says:

Command line error D8016: '/clr' and '/MT' command-line options are incompatible

Is there any specific way to statically link the CRT in a DLL? Also, How can I know which components or libraries are missing when the project is deploying?

Answer 8

There are many similar posts on the forums, so it's a good idea to check what others have experienced, but it's usually one of the following:

-It's 32-bit dll and it needs to be 64-bit.

-The dll or one of the dependencies is not in the deployment package or it's not in the path.

Step 1, make sure your dll is actually in the package. You can view the contents directly or make sure that the target's build properties are set correctly so it ends up wherever you intend for it to go, which is frequently the application's bin directory.

Step 2, understand your dependencies -- run Dependency Walker or Depends on the dll so you know exactly what you depend on. Those libraries need to be in the path and in the package as well.

If you depend on MSVCRTXX.dll, you can link it in statically instead or deploy it as a side-by-side assembly (I haven't tried the latter myself and would like to understand which version of MSVCRT is installed on Azure VMs, if any, and in general, what Microsoft recommends as best practices regarding MSVCRT deployment on Azure).

Answer 9

Hi, thanks for your reply.

I actually have checked many of the posts but they haven't helped me too much. My C++ DLL is being compiled for x64 platforms. Since this DLL is a Hello World application, it does not have any third party dependencies. According to Dependency Walker, this DLL only relies on msvcr100.dll, kernel32.dll and mscoree.dll.

Actually, my DLL is being compiled using Common Language Runtime Support (/clr) to be able to use managed code. I already tried to statically link the CRT, using the /MD compiler option. However, /clr and /MD are incompatible, I cannot use them at the same time. So, even though I want to link statically the CRT, I'm unable due to compiler restrictions.

Is anything else I could do?

 

Answer 10

Hi, here is an update.

I tried to remove the link to the CRT library according to the instructions in this article:
http://msdn.microsoft.com/en-us/library/ms235238.aspx It didn't work either.

This is just a simple ASP.NET application, calling a Hello World C++ DLL, and it seems to be more complicated than it actually should. I've been on this for a couple of days. I wonder if it has happened to someone else. I'm using Visual Studio 2010 on Windows 7, and the .NET framework v4.0. My experiment runs well in the simulation environment but not in the cloud.

I can even share the code. May be I'm missing something very simple.
I really appreciate your feedback.

Answer 11

In a Hello World case I think you can just deploy msvcrt100 to your bin directory and you should be fine. 

Answer 12

Hi, thanks for your feedback.

I put the msvcr100 in my bin directory. I get the following exception:
System.BadImageFormatException: "Could not load file or assembly 'msvcr100' or one of its dependencies. The module was expected to contain an assembly manifest."

It happens in Azure. In my local machine the project works well.

Answer 13

Hi, this is an update.

I used Dependency Walker to check which modules my DLL relies on. I found it has only 3 dependencies: msvcr100.dll, kernel32.dll and mscoree.dll. I then tried to remove the link to the CRT from my DLL according to the information in this article: http://msdn.microsoft.com/en-us/library/ms235238.aspx It didn't work either.

I deployed the msvcr100.dll in the bin directory of my application and got this exception on Azure:
System.BadImageFormatException: "Could not load file or assembly 'msvcr100' or one of its dependencies. The module was expected to contain an assembly manifest."

Any suggestions?

Answer 14

Hi Jccaicedo,

I am moving this thread from “Visual C++ General" forum to the “Windows Azure” forum, since the issue is related to deploy application on Windows Azure. There are more experts in the “Windows Azure " forum.

Cheers,

Yi

 

---

Please remember to mark the replies as answers if they help and unmark them if they provide no help.
Welcome to the All-In-One Code Framework! If you have any feedback, please tell us.

Answer 15

Hello, I'm not sure if it is possible for the OS to search a specific directory for the C Runtime libraries. By default, OS only searches the windows directory, the system32 directory, and the directory where the process's exe is located (in this case, the directory where WaWebHost.exe is located). So even if you ship msvcr100 with your package, it may not work.

I suggest you to ask the question on the VC++ forum, to see if you're able to find a solution to make OS search a specific directory for the C Runtime libraries, such as the approot directory of your Web Role.

By the way, if you have VC 2008 installed on your local machine, and you don't need any new VC 2010 features, you can compile the native application targeting VC9 (2008) runtime, which should work fine in the cloud.

---

Lante, shanaolanxing This posting is provided "AS IS" with no warranties, and confers no rights.

Answer 16

By the way, if you have VC 2008 installed on your local machine, and you don't need any new VC 2010 features, you can compile the native application targeting VC9 (2008) runtime, which should work fine in the cloud.

Hi Yi-Lun,

Thanks for your reply. I changed the target .NET framework from v4.0 to v3.5, for every project in my solution. For non C++ projects I used this information http://msdn.microsoft.com/en-us/library/bb398202.aspx and for C++ projects I changed the target framework according to this information http://msdn.microsoft.com/en-us/library/47w1hdab.aspx

It finally worked! I can now deploy my C++ project on Azure.

Thanks for your help!

Answer 17

I have the same problem and cannot switch back to .NET FW 3.5!!

I got the following error:

"could not load file or assembly or one of its dependencies. The module was expected to contain an assembly manifest. Bad Image Format exception in Azure"

Questions:

Why is this not possible for .NET FW 4.0 ?

What is the root cause of the problem?

Why is the deployment it running in DevFabric without any problems (can load all files)?

Do I really need a manifest file ? For all unmanged dlls ? ...

My C++ Dll is dependent on kernel32.dll and mscoree.dll, do I need to make those both part of the deployment, or is it used from Azure-Cloud-OS (what I would expect!).

BTW, I added msvcr100.dll, msvcp100.dll and vcomp100.dll explicitely to the project already to the project.

How is devfabric dealing with kernel32.dll and mscoree.dll?

Any quick help is highly appreciated ...

Answer 18

Same here. I am having the same issue and I cannot move to 3.5. I haven't been able to load managed c++ dll in the worker role. To narrow down the problem, I wrote a hello world dll in managed c++ which worker role references and also c# dll hello world. Worker role fails to load managed c++ dll but c# dll loads fine.