Using async-await on .net 4

I'm currently starting to create an application that would profit a lot from C# 5's async-await feature. But I'm not sure which version of VS and of the async runtime to use.

Looking at OS popularity charts, I'll need to support Windows XP for another three years or so. It looks like .net 4.5 runs only on newer versions of Windows, so I need to target .net 4.0. The development machines use Windows 7, so using a newer version of VS is not a problem.

Now I need to first choose a compiler for doing this:

• VS2010 with AsyncCTP
• VS2012 Preview (and final once it arrives), setting the target to .net 4.0
• Mono (Looks like 2.12 has async-await, I prefer/am used to VS over MonoDevelop as IDE)

Which one has fewer code-gen bugs? Looking at Jon Skeet's blog the VS2012 Preview uses a never code-generator than the CTP.

And more importantly which runtime to use?

Does VS2012 contain a redistributable async runtime for use with .net 4?

I managed to compile code, with the preview, by referencing the AsyncCTP runtime. But since the CTP has strange licensing conditions, that doesn't look like a good long term solution.

Or should I use a third party implementation? Perhaps mono has one?

For distributing the library I prefer simply putting the dll in the same directory as the application, instead of some kind of installer.

I'd also like it if my binaries would work without changes on mono+Linux/MacOS. So the runtime should either be compatible with whatever mono (2.12 probably) has built in, or allow use on non windows OSs.

Microsoft released the Async Targeting Pack (Microsoft.Bcl.Async) through Nuget as a replacement for the AsyncCTP.

You can read more about it here: http://blogs.msdn.com/b/bclteam/archive/2013/04/17/microsoft-bcl-async-is-now-stable.aspx.

You can read about the previous version here: http://blogs.msdn.com/b/lucian/archive/2012/04/24/async-targeting-pack.aspx.

As this pack is officially supported, I now believe the best option for targeting XP + async would be using Visual Studio 2012 + C#5 + Async Targeting Pack.

If you feel the need to target .NET 3.5 though, you can still use (my) AsyncBridge for .NET 3.5.

from:http://stackoverflow.com/questions/9110472/using-async-await-on-net-4