# LibTmux.FSharp.Window.placementKey

- **Module:** LibTmux.FSharp
- **Package:** LibTmux.FSharp
- **Language:** F#
- **Kind:** function
- **Source:** https://github.com/libtmux/libtmux-dotnet/blob/cf34b255c896d19a97e7d7fabea58609c916012d/src/LibTmux.FSharp/Hierarchy.fsi#L145
- **Page:** https://libtmux.org/en/fsharp/latest/reference/libtmux-fsharp-window-placementkey/

```
val placementKey: window: LibTmux.Window -> WindowPlacementKey
```

Returns a comparable key including the captured session and window index.

## Parameters

- `window` (`LibTmux.Window`)

## Raises

- [`LibTmux.IncompleteSnapshotException`](/en/csharp/latest/reference/libtmux-incompletesnapshotexception/): The placement was not captured.