# LibTmux::Transport

- **Package:** LibTmux
- **Language:** Raku
- **Kind:** module
- **Source:** https://github.com/libtmux/libtmux-raku/blob/e76160bcce6e03976d49424da15b7c31afb2c68e/lib/LibTmux/Transport.rakumod#L2
- **Page:** https://libtmux.org/en/raku/latest/reference/libtmux-transport/

# Bounded child processes

Executor accepts a nonempty positional argv of defined, NUL-free strings.
It invokes that executable directly. Shell syntax, tmux command syntax and
FORMAT expansion belong to callers above this layer.

` execute ` returns a Result. ` execute-async ` always returns a Promise,
including for invalid arguments or closed admission. Each call copies argv,
environment entries and input bytes before asynchronous work begins. An
omitted environment copies the current environment; an explicit empty mapping
passes no variables. Input is a Blob, and the child receives EOF after those
bytes are written. Both output streams are binary and drain concurrently.

` timeout-ms ` bounds an admitted operation, ` max-output-bytes ` bounds combined
retained stdout/stderr, and ` cleanup-timeout-ms ` bounds waiting after forced
termination. Their defaults are 10000 ms, 8388608 bytes and 1000 ms. All are
positive integers. Encoded tmux command size has a separate Engine policy.
` execute ` and ` execute-async ` accept an optional ` timeout-ms ` override for
callers sharing one deadline across several child operations.

By default a nonzero exit or signal throws X::LibTmux::Command. ` :!check `
returns its Result with outcome Failed instead. Spawn failure, invalid input,
timeout, cancellation, output overflow and I/O failures still throw. Error
records retain bounded output bytes, process identity and reaping evidence.
NotStarted means no child effects were admitted. Failed and Indeterminate do
not mean that earlier effects were rolled back. Complete means child process
completion, not completion of a program controlled through tmux.

Cancellation is one shot. Dropping an operation Promise does not cancel its
child. Explicit cancellation and executor close terminate admitted children;
close callers share one Promise. A close failure remains observable on later
close calls. The executor owns direct child clients, not programs deliberately
started in a tmux pane or arbitrary descendant daemons.
Executor and Cancellation cannot be cloned. Result clones reconstruct and
validate replacement attributes, copying output bytes again.

## Members

### Other members

- [`Cancellation`](/en/raku/latest/reference/libtmux-transport-cancellation/) (class): One-shot cancellation shared by explicitly selected operations.
- [`Result`](/en/raku/latest/reference/libtmux-transport-result/) (class): Captured child output. Complete means process completion, not application effects.