# libtmux::kFormatEscape

- **Module:** libtmux
- **Package:** libtmux-cxx
- **Language:** C++
- **Kind:** attribute
- **Source:** https://github.com/libtmux/libtmux-cxx/blob/85e8bd603a322dc32bb8b9aeb1a72bcf36945f1d/include/libtmux/snapshot.hpp#L55
- **Page:** https://libtmux.org/reference/cxx/libtmux-kformatescape/

A separator absent from every format name is not absent from every format value, which is the whole difficulty.

tmux rename-window 'a␞b` is accepted, and one such name used to make every window and pane listing on that server fail to split — data the caller never chose breaking reads of everything else.

So tmux escapes the separator before it can be mistaken for one. U+241B pairs with it and is escaped in turn, which is what makes the transform reversible: `␛S` is a separator that was in the value and `␛E` is an escape marker that was, and neither has a second reading.