libc++ for WebAssembly

This section describes twr-wasm's support for using the standard c++ library libc++ with WebAssembly.

twr-wasm includes libc++ built for WebAssembly in the twr-wasm/lib-c folder.

For C++ the use of libc++ is optional. That is you can build twr-wasm projects in C++ with or without libc++.

See the examples tests-libcx and tests-user for examples of using libc++.

See the balls example for how to create a C++ WebAssembly program without the standard C++ library. The primary advantage to this approach is a bit smaller code size. You don't need to staticly link libc++.

Some of the key options twr-wasm's libc++ for WebAssembly was built with are these:

DLIBCXX_ENABLE_LOCALIZATION=ON 
DLIBCXX_ENABLE_UNICODE=ON 
DLIBCXX_ENABLE_RTTI=ON 
DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=ON 

DCMAKE_BUILD_TYPE=Release       
DCMAKE_CXX_STANDARD=20 

DLIBCXX_ENABLE_EXCEPTIONS=OFF 
DLIBCXX_ENABLE_THREADS=OFF 
DLIBCXX_ENABLE_SHARED=OFF 
DLIBCXX_ENABLE_WIDE_CHARACTERS=OFF 
DLIBCXX_ENABLE_FILESYSTEM=OFF 
DLIBCXX_ENABLE_TIME_ZONE_DATABASE=OFF 
DLIBCXX_ENABLE_MONOTONIC_CLOCK=OFF 
DLIBCXX_ENABLE_RANDOM_DEVICE=OFF