Swift file descriptor library. fd is a minimal layer on-top of the underlying system file descriptor and socket APIs.

FileDescriptor is a protocol containing a single property (fileNumber).

protocol FileDescriptor {
  var fileNumber: FileNumber { get }
}

There are various protocol extensions to FileDescriptor to add functionality.

You may close a file descriptor.

try descriptor.close()

You may use the select function to examine which file descriptors are ready for reading, writing or have error conditions.

let readable = try select(reads: [descriptor]).reads

You may read from a readable file descriptor.

let bytes = try descriptor.read(1024)

You may write to a writable file descriptor.

try descriptor.write([1])

You may use the pipe function to create a unidirectional data flow. The reader allows you to read data which was previously written to the writer.

let (reader, writer) = try pipe()
try writer.write([1])
let bytes = try reader.read(1)

A listener is a file descriptor which can accept connections.

let connection = try listener.accept()

let listener = try TCPListener(address: "127.0.0.1", port: 8000)

UNIXListener is a Unix domain socket listener.

let listener = try UNIXListener(path: "/tmp/my-unix-listener")

A connection conforms to FileDescriptor so you can use the previously documented read and write capabilities.