@bun-win32/ws2_32

Zero-dependency, zero-overhead Win32 WS2_32 bindings for Bun on Windows.

Overview

@bun-win32/ws2_32 exposes the ws2_32.dll exports using Bun's FFI. It provides a single class, Ws2_32, which lazily binds native symbols on first use. You can optionally preload a subset or all symbols up-front via Preload().

The bindings are strongly typed for a smooth DX in TypeScript.

Features

• Bun-first ergonomics on Windows 10/11.
• Direct FFI to ws2_32.dll (BSD sockets, Winsock extensions, DNS resolution, provider catalog, and more).
• In-source docs in structs/Ws2_32.ts with links to Microsoft Docs.
• Lazy binding on first call; optional eager preload (Ws2_32.Preload()).
• No wrapper overhead; calls map 1:1 to native APIs.
• Strongly-typed Win32 aliases (see types/Ws2_32.ts).

Requirements

• Bun runtime
• Windows 10 or later

Installation

bun add @bun-win32/ws2_32

Quick Start

import Ws2_32, { AddressFamily, Protocol, SocketType } from '@bun-win32/ws2_32';

// Initialize Winsock
const wsaData = Buffer.alloc(408);
Ws2_32.WSAStartup(0x0202, wsaData.ptr);

// Create a TCP socket
const sock = Ws2_32.socket(AddressFamily.AF_INET, SocketType.SOCK_STREAM, Protocol.IPPROTO_TCP);
console.log('Socket: %s', sock);

// Clean up
Ws2_32.closesocket(sock);
Ws2_32.WSACleanup();

[!NOTE] AI agents: see AI.md for the package binding contract and source-navigation guidance. It explains how to use the package without scanning the entire implementation.

Examples

Run the included examples:

bun run example              # Winsock TCP socket demo

Notes

• Either rely on lazy binding or call Ws2_32.Preload().
• Windows only. Bun runtime required.
• SAL types & naming: nullability is in the type — Optional<T> (formally optional, SAL _*opt_) and Nullable<T> (plain [in]/[out] the docs say can be NULL), the null sentinel derived from T (null for pointers LP*/P*, 0n for handles/by-value addresses); direction is in the parameter name — _out (_Out_), _in_out (_Inout_), _In_ bare. See AI.md and the repo AGENTS.md.