# libtmux::unexpected_t

- **Module:** libtmux
- **Package:** libtmux-cxx
- **Language:** C++
- **Kind:** typealias
- **Source:** https://github.com/libtmux/libtmux-cxx/blob/393d4b0ad666f18a6581f1eb281741a75a7503f0/include/libtmux/expected.hpp#L47
- **Page:** https://libtmux.org/en/cxx/latest/reference/libtmux-unexpected_t/

The error side of `expected`, named for the rare declaration that has to spell it.

Returning one is how a function reports a failure.