WACS.WASI.Threads 0.2.1

WACS.WASI.Threads

wasi-threads host adapter for the WACS WebAssembly runtime — implements wasi:thread-spawn on top of Wacs.Core's built-in atomics + wait/notify operations. Lets shared-memory wasm modules spawn worker threads against a real System.Threading backend.

Install

dotnet add package WACS.WASI.Threads

Module requirements

The wasm module must:

1. Import or declare a shared memory (memory with the shared flag set).
2. Export wasi_thread_start (param i32 i32) — the worker entry point. WACS calls this with the thread ID (i32) and a user-supplied start argument (i32) per wasi-threads' spec.

Quick start — interpreter / runtime extension

using Wacs.Core.Runtime;
using Wacs.WASI.Threads;

var runtime = new WasmRuntime();
runtime.UseWasiThreads(); // wires wasi:thread-spawn
// (optionally chain other host packages: UseWasiPreview1 / UseWasiPreview2 / ...)

var module = BinaryModuleParser.ParseWasm(File.OpenRead("threaded.wasm"));
var inst = runtime.InstantiateModule(module);
runtime.RegisterModule("app", inst);

if (runtime.TryGetExportedFunction(("app", "_start"), out var addr))
 runtime.CreateInvokerAction(addr).Invoke();

Quick start — CLI

wacs run threaded.wasm --wasi-threads

--wasi-threads is shorthand for --bind Wacs.WASI.Threads. The CLI verifies the module declares shared memory and exports wasi_thread_start before instantiation; missing either trips a clear startup error.

What it provides

• WasiThreadsBindable : IBindable — discovers WACS_WASINN_GGUF_DIR-style host surface, wires wasi:thread-spawn against the shared runtime
• runtime.UseWasiThreads() — chained extension method
• [assembly: WasiHostPackage] marker so runtime.AutoDiscoverHostPackages() picks this assembly up automatically when it's loaded into the AppDomain

Documentation

• Top-level WACS README — Threads
• docs/COMPONENT_CHAINING.md for runtime-requirements composition with other WASI host packages

License

Apache-2.0