Your first Lucet application

Ensure the Lucet command-line tools are installed on your machine

Create a new work directory in the lucet directory:

mkdir -p src/hello

cd src/hello

Save the following C source code as hello.c:

#include <stdio.h>

int main(void)
    puts("Hello world");
    return 0;

Time to compile to WebAssembly! The development environment includes a version of the Clang toolchain that is built to generate WebAssembly by default. The related commands are accessible from your current shell, and are prefixed by wasm32-wasi-.

For example, to create a WebAssembly module hello.wasm from hello.c:

wasm32-wasi-clang -Ofast -o hello.wasm hello.c

The next step is to use Lucet to build native x86_64 code from that WebAssembly file:

lucetc-wasi -o hello.wasm

lucetc is the WebAssembly to native code compiler. The lucetc-wasi command runs the same compiler, but automatically configures it to target WASI. is created and ready to be run: