# tmux.Session.SetUpdateEnvironment

- **Module:** tmux.Session
- **Package:** github.com/libtmux/libtmux-go/tmux
- **Language:** Go
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-go/blob/52968a3181c1c9e6d1b26c565d4b170968ae61c0/tmux/option_generated.go#L7206
- **Page:** https://libtmux.org/en/go/latest/reference/tmux-session-setupdateenvironment/

```
tmux.Session.SetUpdateEnvironment(ctx: context.Context, value: SparseArray[string]) -> (SetArrayResult, error)
```

SetUpdateEnvironment replaces the complete "update-environment" session option array with SparseArray[string], preserving holes and empty values (tmux 3.2a or later). Read it with [SessionOptionValues.UpdateEnvironment] from [Session.Options]; [Session.UnsetOption] restores inheritance or the global default. Replacement is not atomic: the result reports confirmed writes, and failures stop without rollback. Serialize concurrent replacement of the same target and option.