How can I mix the Concurrency Runtime with .NET code?

Question

I've been using the Concurrency Runtime in a C++ static library, and recently wanted to use this library in a C++/CLI project, to take advantage of the Windows Form designer and avoid MFC. Unfortunately, the Concurrency Runtime is not compatible with the /clr switch required in C++/CLI. I tried surrounding the included header files that use the Concurrency Runtime in the "#pragma unmanaged ... #pragma managed" directives, but while that's worked for me with other code in the past, it doesn't seem to work in this case. By which I mean that I get the error:

C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\concrt.h(27): fatal error C1189: #error :  ERROR: Concurrency Runtime is not supported when compiling /clr.

I'm not super well versed in mixing managed and unmanaged code, so it's possible that there's a work-around that I'm not aware of. But on the other hand, perhaps this is just a silly approach. If it weren't for the fact that I find MFC impossibly complex, and the Form designer so nice and easy, I'd just do pure C++. With a preference to mixing the two, any suggestions?

Answer 1

You could consider writing a managed GUI, and have it invoke (using PInvoke) an unmanaged DLL: if you can package the Concurrency Runtime, and the code which uses it, as a DLL.

Answer 2

Using ConcRT in C++/CLI is explicitly disabled in concrt.h via the statement below because it is not officially supported...

#if defined(_M_CEE)
   #error ERROR: Concurrency Runtime is not supported when compiling /clr.
#endif

You can use PInvoke to work around this as suggested above, or you can also use the pointer to implementation idiom to address this by forward declaring a 'pimpl' class and hide the dependency on concrt.h to a native .cpp file which you can then compile into a lib and link against with the header file.

e.g. in the .h file:

//forward declaration
class PImpl;

class MyClass
{
  ....
  //forward declaration is sufficient because this is a pointer
  PImpl* m_pImpl;
}

e.g. in your .cpp file which compiles into a native lib:

  #include <ppl.h>
  class PImpl
  {
   //some concrt class
   Concurrency::task_group m_tasks;
  }