# ControlReply.isError

- **Module:** ControlReply
- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** property
- **Source:** https://github.com/libtmux/libtmux-swift/blob/f02a4668570e1cc5198c941413750e021f42c214/Sources/LibTmux/ControlProtocol.swift#L79
- **Page:** https://libtmux.org/reference/swift/controlreply-iserror/

tmux closed the block with `%error` rather than `%end`. The reason is in ``lines``, the same place a successful reply's output is.