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Jorijn van der Graaf 3e125d83f0 docs: wasm exceptions as the review left them The README called an exception escaping main a trap. It is an uncaught WebAssembly exception, and nothing prints its type or what(); the README says so now. It also lists what a wasm build refuses and why, says that setjmp needs -lsetjmp and that a longjmp across a noexcept function ends the program, that a wasmtime older than 47 needs -W exceptions=y, and that an old wasm-opt on PATH breaks release links. It documents exit and park in a page from EnableWasiBrowserRuntime, with the declaration of the park import. The wasi example still sent Arch users to wasi-libc++, which has no exception-enabled libraries. It asks for a wasi-sdk 33 sysroot or the Flatpak now, and names the browsers a page needs. AGENTS.md notes that the runtime test needs node, so it runs in the native loop and not in CI. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>		2026-10-31 06:10:41 +01:00
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main.cpp	linting	2026-07-23 01:24:42 +02:00
project.cpp	linting	2026-07-23 01:24:42 +02:00
README.md	docs: wasm exceptions as the review left them	2026-10-31 06:10:41 +01:00
serve.sh	SPDX license update	2026-07-22 18:19:17 +02:00

WASI

Build a C++26 program for the wasm32-wasi target and run it in a browser.

Prerequisites

A WASI sysroot with the exception-enabled libc++, lib/wasm32-wasip1/eh/ from wasi-sdk 33 or later: wasm builds compile C++ exceptions and link those libraries. The Flatpak bundles one, which crafter-build uses as it is. Elsewhere, point CRAFTER_BUILD_WASI_SYSROOT at a wasi-sdk sysroot, or set cfg.sysroot in project.cpp. Arch's wasi-libc++ packages have no such libraries, and the build stops with a message saying so.
For the browser: WebAssembly exception handling, in Chrome 137, Firefox 131, Safari 18.4 or newer.

crafter-build

Output lands in bin/wasi-hello-wasm32-wasip1-native/:

wasi-hello.wasm — the compiled module
index.html + runtime.js — a minimal in-browser WASI shim, dropped in by EnableWasiBrowserRuntime(cfg) in project.cpp. Stdout goes to the browser console.

./serve.sh                  # any static file server works

Open http://localhost:8080/. The string from main() shows up in the DevTools console.

If you don't need the browser, drop the EnableWasiBrowserRuntime(cfg) line from project.cpp and run the .wasm directly:

wasmtime bin/wasi-hello-wasm32-wasip1-native/wasi-hello.wasm