# tmux.SessionOptionValues.UpdateEnvironment

- **Module:** tmux.SessionOptionValues
- **Package:** github.com/libtmux/libtmux-go/tmux
- **Language:** Go
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-go/blob/52968a3181c1c9e6d1b26c565d4b170968ae61c0/tmux/option_generated.go#L2293
- **Page:** https://libtmux.org/en/go/latest/reference/tmux-sessionoptionvalues-updateenvironment/

```
tmux.SessionOptionValues.UpdateEnvironment() -> OptionValue[SparseArray[string]]
```

UpdateEnvironment returns materialized "update-environment" as [OptionValue] with value type OptionValue[SparseArray[string]] from session option values; it does not query tmux. Available as STRING since tmux 3.2a; set it with [Session.SetUpdateEnvironment] or [GlobalSessionScope.SetUpdateEnvironment]. Its present SparseArray value preserves assigned tmux indexes, including gaps.