visual studio reports 199711L as its __cplusplus version, even when we are running C++ 14. Do not make decisions based on this macro for the inclusion of C++14 features.

There is a bug report for this that was closed as "deferred" but not actually fixed, it seems:
https://connect.microsoft.com/VisualStudio/feedback/details/763051/a-value-of-predefined-macro-cplusplus-is-still-199711l