DECSET ?1047 — Alt screen without cursor save

Related pitfalls

Known footguns this sequence creates in the wild. Each links to the full symptom + cause + fix.

• ⚠DECSET ?1047 enters alt-screen WITHOUT saving cursor — bare LF at the bottom row still scrolls the alt buffer, exit drops the user back to whatever scrollback the primary buffer had when ?1047l fires·#crlf-under-alt-screen
• ⚠?1047 does NOT clear scrollback on enter / exit — use \x1b[3J (ED 3) before ?1047h if your TUI needs a clean canvas, or migrate to ?1049 (atomic save + clear + enter)·#ed-vs-ed3-scrollback

Frequently asked

Short answers to the questions developers actually search for this sequence.

When should I use ?1047 instead of ?1049?

Almost never — ?1049 is what every modern TUI should use. ?1049 is *atomic*: it saves the cursor (DECSC), switches to the alt buffer, and clears it in one operation; ?1049l reverses all three. ?1047 only does the buffer switch — no cursor save, no clear — so you have to emit \x1b7 (DECSC) and \x1b[2J (or \x1b[3J for scrollback) yourself, in the right order, with matching cleanup on exit. The only reason to pick ?1047 today is targeting a legacy terminal whose ?1049 implementation is broken (none in the modern matrix qualifies) — and even then, ?1047 plus explicit DECSC / clear gets you ?1049 behaviour at the cost of more bytes and more failure surface.

Does ?1047 preserve the scrollback when entering / exiting?

Yes — ?1047 leaves the *primary* buffer's scrollback intact across the round-trip. The alt buffer itself has no scrollback (it's a fixed-size screen-shaped buffer with no history). When you exit ?1047l, the primary buffer's pre-?1047h scrollback is back exactly as it was; the alt buffer's content is discarded. If you want a clean alt canvas, emit \x1b[3J (ED 3 — clear scrollback) before ?1047h on the alt side, or just use ?1049 which handles the clear in the same atomic operation.