GATM Guarded Area Transfer Mode
Whether guarded areas are left out when the screen is sent to the host.
CSI 1 h
Mode 1 decides whether the contents of guarded areas are sent when the terminal transmits the screen to the host. A guarded area is one marked off with SPA and EPA. Terminals that do not transmit their screen have no use for it.
| State | ECMA-48 calls it | Meaning |
|---|---|---|
Reset, CSI 1 l | GUARD | only the unguarded areas are sent |
Set, CSI 1 h | ALL | the guarded areas are sent as well |
DEC STD 070 does not list it, but the VT510 manual’s table of ANSI modes for DECRPM gives it as permanently reset, and DEC STD 070 says DECRQM reports every X3.64 mode as set or reset.
xterm ignores CSI 1 h and CSI 1 l (ansi_modes handles only modes 2, 4, 12 and 20), and DECRQM reports the mode as permanently reset, 4 (do_ansi_rqm). libghostty-vt ignores it too, but does not recognize the number, so it answers DECRQM with 0. Both DECRQM cases are known differences.
Validation
GATM-1: Reported as permanently reset
\e[1$p
|_____|
reply \e[1;4$y
GATM-2: Even after it is set
\e[1h
\e[1$p
|_____|
reply \e[1;4$y