# libtmux::Pane::expand

- **Module:** libtmux::Pane
- **Package:** libtmux-cxx
- **Language:** C++
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-cxx/blob/85e8bd603a322dc32bb8b9aeb1a72bcf36945f1d/include/libtmux/entities.hpp#L703
- **Page:** https://libtmux.org/reference/cxx/libtmux-pane-expand/

```
libtmux::Pane::expand(format: std::string_view) -> expected< std::string, CommandFailure >
```

Ask tmux to expand a format against this pane.

`#{pane_current_command}` and `#{pane_current_path}` are the two most callers reach for, and neither is a field this class carries: both change under a value that stays still.

Guarded like the session and window forms, because tmux answers a pane that has gone with a blank and a zero exit status.