@bun-win32/winspool

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

Overview

@bun-win32/winspool exposes the winspool.drv exports using Bun's FFI. It provides a single class, Winspool, 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 winspool.drv (printer management, print jobs, spooler control, driver management, and more).
• In-source docs in structs/Winspool.ts with links to Microsoft Docs.
• Lazy binding on first call; optional eager preload (Winspool.Preload()).
• No wrapper overhead; calls map 1:1 to native APIs.
• Strongly-typed Win32 aliases (see types/Winspool.ts).

Requirements

• Bun runtime
• Windows 10 or later

Installation

bun add @bun-win32/winspool

Quick Start

import Winspool from '@bun-win32/winspool';

// Get the default printer name (sizing call, then read)
const sizeBuffer = Buffer.alloc(4);
Winspool.GetDefaultPrinterW(null, sizeBuffer.ptr);

const charsNeeded = sizeBuffer.readUInt32LE(0);
const nameBuffer = Buffer.alloc(charsNeeded * 2);
sizeBuffer.writeUInt32LE(charsNeeded, 0);

Winspool.GetDefaultPrinterW(nameBuffer.ptr, sizeBuffer.ptr);
const printerName = new TextDecoder('utf-16').decode(nameBuffer).replace(/\0.*$/, '');
console.log('Default printer:', printerName);

[!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              # Default printer + printer enumeration

Notes

• Either rely on lazy binding or call Winspool.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.