# Socket and servers

Source: https://libtmux.org/en/cxx/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

[`Server::at_default()`](<https://libtmux.org/en/cxx/latest/reference/libtmux-server-at_default/>) selects the default socket. Use
[`Server::at_socket_name("work")`](<https://libtmux.org/en/cxx/latest/reference/libtmux-server-at_socket_name/>) for a named socket or
[`Server::at_socket_path(path)`](<https://libtmux.org/en/cxx/latest/reference/libtmux-server-at_socket_path/>) for an explicit path.

```cpp
auto named = libtmux::Server::at_socket_name("work");
```

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

## 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.is_alive`](<https://libtmux.org/en/cxx/latest/reference/libtmux-server-is_alive/>) takes a timeout and returns a boolean.

```cpp
if (server.is_alive(std::chrono::seconds{2})) {
  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 [`server.kill()`](<https://libtmux.org/en/cxx/latest/reference/libtmux-server-kill/>) and inspect its result for a failure.

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.