wasm3/docs/Cookbook.md

Wasm3 cookbook

Rust WASI app

TODO

AssemblyScript WASI app

TODO

TinyGo WASI app

TODO

Zig WASI app

Create hello.zig:

const std = @import("std");

pub fn main() !void {
    const stdout = std.io.getStdOut().writer();
    try stdout.print("Hello, {s}!\n", .{"world"});
}

$ zig build-exe -O ReleaseSmall -target wasm32-wasi hello.zig

$ wasm3 hello.wasm
Hello, world!

Zig library

Create add.zig:

export fn add(a: i32, b: i32) i64 {
    return a + b;
}

$ zig build-lib add.zig -O ReleaseSmall -target wasm32-freestanding

$ wasm3 --repl add.wasm
wasm3> add 1 2
Result: 3

C WASI app

The easiest way to start is to use Wasienv.

C/C++ WASI app

Create hello.cpp:

#include <iostream>
int main() {
    std::cout << "Hello, world!" << std::endl;
    return 0;
}

Or hello.c:

#include <stdio.h>
int main() {
   printf("Hello, %s!\n", "world");
   return 0;
}

$ wasic++ -O3 hello.cpp -o hello.wasm
$ wasicc -O3 hello.c -o hello.wasm

$ wasm3 hello.wasm
Hello World!

Limitations:

• setjmp/longjmp and C++ exceptions are not available
• no support for threads and atomics
• no support for dynamic libraries