# FormatSubscription

- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** struct
- **Source:** https://github.com/libtmux/libtmux-swift/blob/f02a4668570e1cc5198c941413750e021f42c214/Sources/LibTmux/Watch.swift#L11
- **Page:** https://libtmux.org/reference/swift/formatsubscription/

A format tmux reports changes to, rather than being asked for.

`refresh-client -B` registers one against a control connection. tmux then
evaluates the format about once a second and sends
``SubscriptionChange`` whenever the value differs from the last one it
sent — so "has the foreground command changed?" costs no commands, no
captures, and no scrollback at all.

Requires tmux 3.2 or later, which is this package's floor.

## Members

- `!=(_:_:)` (function) — Returns a Boolean value indicating whether two values are not equal.
- `Scope` (enum) — What tmux evaluates the format against.
- `name` (property) — What changes are reported under, and what ``ControlSession/stopWatching(_:)`` names.
- `scope` (property)
- `format` (property) — A tmux format, such as `#{pane_current_command}`.
- `init(name:scope:format:)` (method)