As I originally pointed out, the difference between C++ and C++/CLI is that C++/CLI is not just a superset of standard C++. Things are changed or missing, not j

As I originally pointed out, the difference between C++ and C++/CLI is that C++/CLI is not just a superset of standard C++. Things are changed or missing, not just added. You can't just take a pre-existing standard C++ program and drop it in a C++/CLI compiler because you'll hit all those differences. (Things may have been better in the past, but the C++/CLI spec has not kept up with the C++ standard at all and so the main implementation, when asked for "C++17 and C++/CLI," just kind of shrugs and makes a mess.) This is not true of emscripten. It does add some Javascript binding functionality, but that's no different from e.g. Linux or Windows offering their own platform APIs beyond the C++ standard library. You can just take a lot of pre-existing standard C++ programs, often including those that use platform-specific APIs, and drop it in emscripten!