DSR — Device Status Report

Sequence	CSI <Ps> n
Bytes	0x1B 0x5B <Ps> 0x6E
Category	CSI
Mnemonic	DSR
Otty support	✓ Implemented (Ps = 5, 6)

Description

A host program asks the terminal about its state and the terminal answers by writing a reply back up the PTY. Otty answers two queries immediately:

Query	Reply	Meaning
CSI 5 n	CSI 0 n	Terminal is ready / OK (no malfunction).
CSI 6 n	CSI <row> ; <col> R	Cursor Position Report (CPR). row / col are 1-based.

The CSI 6 n form is the one most programs care about: it's how a shell or TUI discovers where the cursor actually landed after printing text — for example to detect whether a prompt left a trailing partial line, or to measure the width of already-emitted output.

Example

# Ask for the cursor position. The reply (e.g. `\e[12;1R`) is written to the
# terminal's input, so in a raw-mode program you'd read it back from stdin.
printf '\e[6n'

# Ask whether the terminal is OK — reply is `\e[0n`.
printf '\e[5n'

Because the reply arrives on the same channel as keyboard input, capturing it requires the program to put the terminal in raw mode and read stdin; you won't see the response if you just run the printf at an interactive shell prompt (the shell consumes it).

Not supported

• DECXCPR (CSI ? 6 n) — the DEC private variant that adds a page number, replying CSI ? <row> ; <col> ; <page> R. Otty implements only the standard CSI 6 n form above. Single-page terminals essentially never need DECXCPR.
• Other Ps values (e.g. printer / keyboard / locator status) are not answered.

Related

• CUP — Cursor Position — moves the cursor to the position DSR reports.
• ESC 7 / ESC 8 — save / restore the full cursor state.
• Terminal identification — DA / XTVERSION and other reports the terminal sends about itself.

Notes

• The reply is sent as a PTY write, ordered with respect to other output the terminal generates.
• Positions are reported relative to the viewport (or the scrolling region when origin mode DECOM / ?6 is active), matching how CUP interprets them.