# ControlSession.watch(_:)

- **Module:** ControlSession
- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-swift/blob/f02a4668570e1cc5198c941413750e021f42c214/Sources/LibTmux/Watch.swift#L136
- **Page:** https://libtmux.org/reference/swift/controlsession-watch(_-)/

```
ControlSession.watch(_:)(subscription: FormatSubscription) -> ()
```

Registers a format subscription on this connection.

## Raises

- `TmuxError`