an opinionated terminal multiplexer in C with programmable pane chrome https://git.sl0p.foo/slosh.git/atom/tests/test_own_pane.py?h=master 2026-09-29T12:26:06Z 2026-09-29T12:26:06Z user user@clank 2026-09-29T12:26:06Z urn:sha1:e779c1fafa556330752b2c5f43c56415f655ff24 A program in a pane could name every pane but its own. `panes` says which one is *focused*, and focus belongs to the human, so anything that inferred "where do I live" from it did its work in whichever tab somebody else happened to be looking at -- and lost a race with anybody else asking the same question. So export the id into the child, the way tmux has $TMUX_PANE and zellij $ZELLIJ_PANE_ID. The id is taken before the pane is made, because pane_new spawns the program and assigning it afterwards is one instruction too late; it lives on the pane rather than the layout, so a rerun keeps it -- an identity that changed under a rerun would be no identity at all. Unset, not zero, when there is none: a stale value inherited from an outer session would read as this one's. `panes` also reports each pane's pid now, which is the same question answered for anything that cannot read its own environment: walk your parents up until one of them is on that list.