Although commit:
https://github.com/EpicGames/UnrealEngine/commit/49a26f3c0132c5388f6e375747eba7517b70dba8
added support for this, it was then removed by:
https://github.com/EpicGames/UnrealEngine/commit/bfd78e5d15c0a04174eb748d2a51141f34d7c7d0
The current master does NOT support C++11 features on IOS.
I presume there’s some justification for this, but its kind of rubbish; the engine documentation says to use C++11, and that’s the library it uses on OSX; there’s no reason as far as I’m aware to use libstdc++ instead of libc++ for IOS applications.
To see this in action, try using:
#include <functional>
template<typename TOut>
void Foo(std::function< void(TOut value)> handler) {
// ...
}