# FormatSubscription

- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** struct
- **Source:** https://github.com/libtmux/libtmux-swift/blob/254f8b2be7eb60cacc3ffcb3ea8e456784f582df/Sources/LibTmux/Watch.swift#L12
- **Page:** https://libtmux.org/en/swift/latest/reference/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)