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Diffstat (limited to 'docs/fs.md')
| -rw-r--r-- | docs/fs.md | 18 |
1 files changed, 18 insertions, 0 deletions
@@ -378,6 +378,24 @@ pane a look focused or the pane an exec acted on (even one it closed), one per line; a look that found text answers the pane the text is selected in, not the hits buffer it opened. +The answer belongs to the open, as /net/tcp/clone's does: an open that +wrote reads what its own last write touched, from the start after each +write, whatever offset the read comes at (a shell's `exec 3<>look` shares +one offset between its write and its read, as with `pty/run`); an open +that never wrote reads the session's last answer as it stood when it was +opened. So `echo x > look; cat look` works for one client, but two +clients doing it at once may read each other's; for that, write and read +on one open: `exec 3<>$m/look; echo x >&3; cat <&3; exec 3<&-`. + +A write of command lines -- to `look`, `exec`, `tagexec`, a `ctl` of the +root, a pane or a column, or a column's `exec` -- runs each line once it is +whole: a mount cuts a big write at its message size (4 KiB through the +kernel's, 8 KiB from a client that asks), anywhere, and each piece comes as +a write of its own, so the open keeps a last line with no newline yet, or +an Edit block whose text has not ended, until its next write, and runs it +then; what is left when it closes runs at the close. A fragment never runs +on its own. A line or Edit block held past 1 MiB is refused (EINVAL). + A look takes acme's addresses after a colon (editors/acme/look.c:450): a line written to `look` as `file:/re/`, `file:#n`, `file:$` or any address opens (or finds) the file and selects what the address names. **The |