Windows

Type-safe, policy-free wrappers around Windows kernel syscalls for Swift. Provides I/O Completion Port (IOCP) primitives with typed throws and full Sendable compliance.

---

Key Features

• Typed throws end-to-end – Every error type is statically known; no any Error escapes the API surface
• Swift 6 strict concurrency – Full Sendable compliance with documented thread-safety guarantees
• I/O Completion Ports – High-performance async I/O via CreateIoCompletionPort and GetQueuedCompletionStatus
• Policy-free design – Raw syscall wrappers without opinions on scheduling, buffering, or lifecycle
• Batch dequeuing – Efficient multi-completion retrieval via GetQueuedCompletionStatusEx
• Cancellation support – Fire-and-forget and status-returning cancel operations via CancelIoEx

---

Installation

Package.swift dependency

dependencies: [
    .package(url: "https://github.com/coenttb/swift-windows.git", from: "0.1.0")
]

Target dependency

.target(
    name: "YourTarget",
    dependencies: [
        .product(name: "Windows Kernel", package: "swift-windows")
    ]
)

Requirements

• Swift 6.2+
• Windows

---

Quick Start

import Windows_Kernel

// Create an I/O completion port
let port = try Kernel.IO.Completion.Port.create(threads: 0)
defer { Kernel.IO.Completion.Port.close(port) }

// Associate a file handle (opened with FILE_FLAG_OVERLAPPED)
try Kernel.IO.Completion.Port.associate(port, handle: fileHandle, key: 1)

// Set up overlapped structure for async operation
var overlapped = Kernel.IO.Completion.Port.Overlapped()

// Initiate async read
let result = try Kernel.IO.Completion.Port.read(fileHandle, into: buffer, overlapped: &overlapped.raw)

// Wait for completion
let item = try Kernel.IO.Completion.Port.Dequeue.single(port, timeout: Kernel.IO.Completion.Port.Error.Code.Wait.infinite)
print("Read \(item.bytes) bytes with key \(item.key)")

---

Architecture

Type	Description
Windows	Namespace enum for Windows-specific APIs
Kernel.IO.Completion.Port	I/O Completion Port syscall wrappers
Kernel.IO.Completion.Port.Key	Completion routing key (integer or pointer)
Kernel.IO.Completion.Port.Overlapped	Async operation state (OVERLAPPED wrapper)
Kernel.IO.Completion.Port.Dequeue	Single and batch completion retrieval
Kernel.IO.Completion.Port.Cancel	Cancellation operations (all or specific)
Kernel.IO.Completion.Port.Error	Typed error cases with Win32 error codes

---

Platform Support

Platform	CI	Status
Windows	✅	Full support
macOS/Linux/iOS	—	Not supported

This package provides Windows-specific IOCP APIs. For cross-platform kernel primitives, see swift-kernel-primitives.

---

Related Packages

Dependencies

• swift-kernel-primitives: Cross-platform kernel types (Kernel.Descriptor, Kernel.Error)

Used By

• swift-io: Async I/O executor built on kernel primitives

---

License

This project is licensed under the Apache License v2.0. See LICENSE.md for details.