In fact, the problem with having one single &quot;reference implementation&quot;, like in Python, is that other implementations never get to be &quot;compliant enough&quot;.<p>The situation in C++ is saner, since both GCC and Clang are moving the standard forward, and together make sure that the standard can accept multiple valid implementations and code tends to be truly portable.<p>The problem is really simply that Microsoft was never interested, at least until very recently, to have a truly standards compliant compiler.