XTGETTCAP: Request Termcap/Terminfo String

Status: xterm.

XTGETTCAP asks the terminal for the value of a terminfo capability by name. It lets an application learn what the terminal thinks its terminfo says without a terminfo database on the local machine, which matters over SSH, in containers, and for terminals whose entry is not installed.

Syntax

DCS + q hex-name [ ; hex-name ]… ST          request
DCS 1 + r hex-name = hex-value [ ; … ] ST     reply, valid
DCS 0 + r [ hex-name ] ST                     reply, invalid

Names and values are hex-encoded ASCII: TN is 544e, Co is 436f, RGB is 524742. Several names may be requested at once; xterm answers all of them in one reply and reports 0 if any name is unknown. Other terminals may answer each name separately or omit unknown names from a 1 reply, so parse the reply by name rather than by position.

xterm gates this behind allowTcapOps, which is true by default but frequently disabled by distributions.

Useful names

Name	Meaning	Why ask
TN	Terminal name	The terminfo entry the terminal wants; xterm answers with its termName
Co / colors	Number of colors	256 versus 16777216
RGB	Direct color capability	Terminfo's spelling of truecolor support
Tc	Truecolor (tmux convention)	The other spelling; ask for both
Smulx	Styled underline	CSI 4 : Ps m support
Setulc	Underline color	CSI 58 ; … m support
Sync	Synchronized output	Mode 2026 as a terminfo string
Ss / Se	Set/reset cursor style	DECSCUSR support
kitty-query-*	kitty-specific	Answered only by kitty; see its docs

Key-related names (kf1, kcuu1, …) are also useful: they tell an application the encoding the terminal will actually send.

Probe

# TN ; Co ; RGB
tools/query '\033P+q544e;436f;524742\033\\'

Decode the reply with xxd -r -p on each hex-name=hex-value pair.

Sources

• XTerm Control Sequences
• terminfo(5)
• kitty: XTGETTCAP

Compatibility

Feature support by terminal. Imported claims have not been reverified; unknown is not unsupported.

Feature / stable ID	Alacritty	Apple Terminal	ConPTY (conhost)	Contour	DomTerm	foot	Ghostty	iTerm2	kitty	Konsole	mintty	mlterm	PuTTY	Revenant	RLogin	st	tmux	rxvt-unicode	VTE	wayst	WezTerm	Windows Terminal	xterm	xterm.js
XTGETTCAP dcs-xtgettcap	Unknown	Unknown	Unknown	SupportedImported · unverified	Unknown	SupportedImported · unverified	SupportedImported · unverified	Unknown	SupportedImported · unverified	Unknown	SupportedImported · unverified	Unknown	Unknown	Partial	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	SupportedImported · unverified	UnknownImported · unverified	SupportedImported · unverified	UnknownImported · unverified