# ControlSession.watch(_:)

- **Module:** ControlSession
- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-swift/blob/254f8b2be7eb60cacc3ffcb3ea8e456784f582df/Sources/LibTmux/Watch.swift#L137
- **Page:** https://libtmux.org/en/swift/latest/reference/controlsession-watch(_-)/

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

Registers a format subscription on this connection.

## Raises

- `TmuxError`