TcpListener

public struct TcpListener { /* private fields */ }

A bound, listening TCP server socket.

Created by TcpListener.bind(port:) — sets SO_REUSEADDR, binds to INADDR_ANY:port, and calls listen(2) with backlog 128. Accept connections via accept(), which blocks until the next client arrives. The owned fd is closed by the deinit.

Examples

let listener = match TcpListener.bind(8080) {
    .Ok(l) => l,
    .Err(e) => return .Err(e)
};
while true {
    match listener.accept() {
        .Ok(stream) => /* handle stream */ {},
        .Err(e) => break
    }
}

Representation

A single Int32 field — the listening socket fd.

Memory Model

Owns its fd; closed on drop.

Properties

var fd: Int32

Initializers

init(Int32)

Internal — wraps an existing fd. Callers should use bind(port:).

Methods

public func accept() -> Result[TcpStream, IoError]

Blocks until the next client connects, then returns it as a TcpStream.

Discards the client's address — pass non-null pointers to libc.accept directly if you need it. Each accepted connection has its own fd, independent of the listener.

Errors

Returns Err(IoError.last()) if accept(2) fails — common causes include EINTR (interrupted by signal) and EMFILE (per-process fd limit).

public static func bind(UInt16) -> Result[TcpListener, IoError]

Creates a server socket bound to 0.0.0.0:port with SO_REUSEADDR and a backlog of 128.

Walks the full setup — socket → setsockopt → bind → listen — and cleans up the partial fd on any failure.

Errors

Returns Err(IoError.last()) (captured errno) at any of the four steps; the most common case is EADDRINUSE if another process holds the port and SO_REUSEADDR is not enough.

Examples

let listener = TcpListener.bind(8080);

public func rawFd() -> Int32

Returns the underlying listening fd without giving up ownership.

Defined in lang/std/net/socket.ks