{
  "id": "terminal-dec-private-mode/1047",
  "family": "terminal-dec-private-mode",
  "slug": "1047",
  "title": "DECSET 1047 — Alternate screen buffer (clear on exit)",
  "summary": "CSI ? 1047 h switches to the alternate screen buffer; CSI ? 1047 l switches back to the normal buffer AND clears the alternate buffer as it leaves. Unlike 47 it tidies the alt buffer on exit, but unlike 1049 it does not save/restore the cursor. Usually combined with 1048; 1049 is the all-in-one.",
  "kind": "control-sequence",
  "aliases": [
    "alternate screen",
    "alt buffer clear",
    "DECSET 1047",
    "?1047h / ?1047l"
  ],
  "status": "de-facto",
  "verification": "verified",
  "tier": "B",
  "source_url": "https://invisible-island.net/xterm/ctlseqs/ctlseqs.html",
  "source_version": "xterm ctlseqs, patch #410, 2026/04/19",
  "retrieved_date": "2026-05-29",
  "attribution": [
    {
      "claim_ref": "#summary",
      "source_url": "https://invisible-island.net/xterm/ctlseqs/ctlseqs.html",
      "source_version": "xterm patch #410, 2026/04/19",
      "note": "xterm ctlseqs: Ps = 1 0 4 7 -> Use Alternate Screen Buffer; clears it first if returning to the normal buffer (i.e. clears on exit)."
    }
  ],
  "see_also": [
    "terminal-dec-private-mode/47",
    "terminal-dec-private-mode/1048",
    "terminal-dec-private-mode/1049"
  ],
  "ext_type": "terminal-escape@1",
  "ext": {
    "csi_or_osc": "DEC-private-mode",
    "command_number": 1047,
    "frame": {
      "introducer_7bit": "\u001b[?",
      "introducer_7bit_readable": "ESC [ ? (0x1B 0x5B 0x3F)",
      "introducer_8bit": "›?",
      "introducer_8bit_readable": "0x9B ? (8-bit CSI + '?')",
      "note": "DEC private mode (CSI with '?' private prefix). Set = final byte 'h' (DECSET); reset = final byte 'l' (DECRST). Self-terminating."
    },
    "terminator": "none",
    "terminator_detail": {
      "note": "No string terminator: the enable/disable ends at the final byte 'h'/'l'."
    },
    "params": [
      {
        "id": "set",
        "anchor": "#set",
        "name": "Enable (DECSET)",
        "meaning": "CSI ? 1047 h switches to the alternate screen buffer.",
        "required": true,
        "byte_sequence_ST": "\u001b[?1047h",
        "byte_sequence_ST_readable": "ESC [ ? 1 0 4 7 h   ==  \\x1b[?1047h   (set / DECSET)",
        "subparams": []
      },
      {
        "id": "reset",
        "anchor": "#reset",
        "name": "Disable (DECRST)",
        "meaning": "CSI ? 1047 l switches back to the normal buffer and CLEARS the alternate buffer on the way out (unlike legacy mode 47).",
        "required": true,
        "byte_sequence_ST": "\u001b[?1047l",
        "byte_sequence_ST_readable": "ESC [ ? 1 0 4 7 l   ==  \\x1b[?1047l   (reset / DECRST)",
        "subparams": []
      }
    ],
    "gotchas": [
      "1047 CLEARS the alt buffer when leaving (better than 47) but does NOT save/restore the cursor — pair it with 1048, or just use 1049 which bundles save-cursor + clear + switch.",
      "Because it doesn't save the cursor, leaving 1047 can drop you at an unexpected cursor position; restore it yourself or use 1048/1049.",
      "Don't mix 1047 enter with 1049 leave (or vice versa) — the save/clear semantics won't match.",
      "tmux/screen interpret alt-screen modes; be consistent within a multiplexer.",
      "For new code prefer DECSET 1049."
    ],
    "v1_smoke_test": {
      "asserts": "Alt-screen clear-on-exit set/reset (?1047h / ?1047l) render as byte-exact DEC-private-mode sequences; clears-on-exit but no-cursor-save distinction recorded.",
      "behavioral_conformance": "deferred to v2."
    }
  },
  "updated": "2026-05-29T00:00:00Z"
}