[CmonDev]

C# is in front of all three in mobile space (it compiles to native of course).

C# is the only language that is both modern and spans all major mobile platforms.

http://en.wikipedia.org/wiki/Xamarin

[josteink]

Sure. But Xamarin is hardly open-source, and what OP was looking for was a open-sourced tool-chain & stack for mobile development.

[jacobbudin]

You can't even build Xamarin's sample project without demoing a commercial license, because the sample project is falls outside the app size restriction.

[pjmlp]

Except you are forgetting C++11 is supported in all mobile SDKs, with C++14 appearing in upcoming versions.

Personally I consider C++14 quite modern.

[zak_mc_kracken]

Considering the minuscule market share that Windows Mobile currently has, C# is close to nonexistent on mobile as of today.

[CmonDev]

Unity3d alone completely invalidates this claim.

[mnem]

Are there many apps written in Unity? Or is it only games?

[_random_]

Mostly games which are a kind of apps. And games are the most popular apps, e.g.: http://www.statista.com/statistics/270291/popular-categories....