Windows Phone 7 and native C++/CLI

Question

Microsoft recently released tools and documentation for its new Phone 7 platform, which to the dismay of those who have a big C++ codebase (like me) doesn't support native development anymore. Although I've found speculation about this decision being reversed, I doubt it. So I was thinking how viable would be to make this codebase available to Phone 7 by adapting it to compile under C++/CLI. Of course the user interface parts couldn't be ported, but I'm not sure about the rest. Anyone had a similar experience? I'm not talking about code that does heavy low-level stuff - but there's a quite frequent use of templates and smart pointers.

Answer 1

c++/cli can theoretically be used with WPF/Silverlight using the trick of replacing the C# generated from the XAML with a macro definition that can be used inside the main class in a code behind file. I worked out this technique but haven't had the motivation to take it beyond theory - I'm quite happy mixing languages.

As far as using c++/cli in a pure safe mode for your logic code, this may still not be possible but I'd love to hear how someone goes trying it now. Whilst researching it for Silverlight back in 2008 I found this daunting silverlight forum comment:

I just gave Silverlight&C++ it a try by compiling the MSIL from my C++ project into a Silverlight-compatible DLL. The good news: it works, and you can call this code from a Silverlight project. The bad news: The C++ compiler apparently uses MSIL instructions that Silverlight disallows.

So, if you try this, even with the simplest of programs, you'll almost immediately get the exception "Operation could destabilize the runtime." To me, this makes it seem less likely that we'll see Silverlight for C++ soon, as the compiler will need to behave quite a bit differently.

Answer 2

You can generate verifiable managed code in C++/CLI using the /clr:safe option. The problem is that most of your normal c++ code will not compile with that option.

Answer 3

C# is currently the only supported language for WinPhone7.

I fully expect that MS will add support for VB and C++/CLI in the future too, but don't expect to open up the native-code kimono anytime soon.

Native code just has too many issues to overcome, specifically around security, reliability, etc. Managed code is FAR easier to statically verify and FAR easier to control while running.

If you're upset about porting C++ code to C#, just be glad MS didn't force you to have to move to Objective-C ;)

From our own experience, the proces of porting well-written C++ to C# actually takes a lot less effort than one might at first expect. Sure, there's a learning curve, but you have that with any port. We actually got so much benefit from porting our core app and data engines to C# that we re-tooled our entire team to code in C# and port our C# back to C++ where necessary rather than the other way around! So far, we've only ported two modules back to C++ and call our C# code from our native code via interop instead.

Again, remember, WinPhone is a brand new platform using best of breed, highly-productive, next-generation development tools and platforms. It is not your father's WinMo.

If support for C++ is something you find to be crucially important, then make sure MS know - (respectfully and professionally) state your position in the MSDN forums and at developer events near you.

Update1: 2012-12-17:

While native C++ still isn't officially supported for Windows Phone 7, Windows Phone 8 now supports native C++ code so you can more easily port your existing C++ codebase(s) to Windows Phone 8 (as well as Windows 8 and Windows desktop apps).

While there isn't 100% compatibility between the Windows8/Phone8 platforms and API's right now, I expect the two platforms to become increasingly integrated over the next couple of releases.

This is especially true now that one of the key barriers to closer cooperation between Windows and other groups at Microsoft recently left the company ;)

Update2: 4/15/2014:

As per the recent announcements at //BUILD/ 2014, you can now start building "universal" apps in C++ & XAML, C#/VB & XAML or JavaScript & HTML that will run on Windows 8.1, Windows Phone 8.1 and Xbox One! For more details on building Windows Phone 8.1 Universal Apps, read this article.

Answer 4

The whole development idea is built on Silverlight. I think you can add your managed dll written in C++ without any problem to this Silverlight project, but it could not use native code.

I am planning to install the tools on my machine tonight and will try this out.