# Socket and servers

Source: https://libtmux.org/en/swift/latest/topics/socket-and-servers/

> Select a server socket, check liveness, and detect a replacement daemon.

A tmux server is selected by its Unix-domain socket. Use different sockets for
independent servers, such as a development session and an isolated test server.
Choose the default socket, a named socket (`-L`), or an explicit path (`-S`).

## Naming a server

Select a named socket with [`Server(socketName: "work")`](<https://libtmux.org/en/swift/latest/reference/server/>) or an
explicit path with [`Server(socketPath: path)`](<https://libtmux.org/en/swift/latest/reference/server/>). The initializer requires
a socket selection; see the default-socket example below.

```swift
let named = try Server(socketName: "work")
```

Choose either a socket name or a socket path. tmux uses `TMUX_TMPDIR` to
resolve the directory for default and named sockets.

Swift requires an explicit `socketPath` or [`socketName`](<https://libtmux.org/en/swift/latest/reference/endpoint-socketname(_-)/>) argument. To reach
tmux's default socket, use [`Server(socketName: "default")`](<https://libtmux.org/en/swift/latest/reference/server/>).

## Is the server actually there?

A server handle does not prove that the target server is running. Use a liveness
check when your program needs to distinguish a live server from an unavailable
socket:

[`Server.isRunning`](<https://libtmux.org/en/swift/latest/reference/server-isrunning()/>) is an async throwing check that returns [`Bool`](<https://developer.apple.com/documentation/swift/bool>).

```swift
if try await server.isRunning() {
    try await server.sessions()
}
```

## Killing a server, and telling two apart

Killing a server ends all its sessions. Use this only for a server your program
owns; for narrower cleanup, kill the session or pane you created.

Call [`try await server.killServer()`](<https://libtmux.org/en/swift/latest/reference/server-killserver()/>) and handle a cleanup failure before returning.

A restarted server can reuse a socket path while having different state. Do
not treat a matching path as proof that a cached object still exists.