zjkmxy / wasmer-example

Requirements

One of the following compilers is enough.

Install WASM-SDK and WASMER

Wasienv seems to be abandoned. Use the following command in a setup folder to download MacOS builds.

export WASI_VERSION=20
export WASI_VERSION_FULL=${WASI_VERSION}.0
wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_VERSION}/wasi-sdk-${WASI_VERSION_FULL}-macos.tar.gz
tar xvf wasi-sdk-${WASI_VERSION_FULL}-macos.tar.gz

Then, in bashrc, export WASISDK_DIR to be the bin folder.

Install wasmer via Homebrew brew install wabt wasmer.

To check:

${WASISDK_DIR}/clang++ -v
# clang version 16.0.0 (https://github.com/llvm/llvm-project 08d094a0e457360ad8b94b017d2dc277e697ca76)
# Target: wasm32-unknown-wasi
# Thread model: posix

wasmer --version
# wasmer 3.3.0

Now we can use wasmc++ and wasic++ to compile C++ sources into WASM/WASI.

Install Emscripten

Install with brew install emscripten

To check:

emcc --version
# emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.39-git
# Copyright (C) 2014 the Emscripten authors (see AUTHORS.txt)
# This is free and open source software under the MIT license.
# There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Differences between compilers

• wasic++ will include the standard library.
• wasmc++ will not include any extra library. The generated wasm will be very small in size.
  • Note: wasic++ will also include syscalls, but by default Wasmer does not expose them.
• Emscripten is more "on the browser's side".

Compilation

Execute make in csrc folder to compile C++ code into WASM. Then you can execute the main program by go run ..