# Libtmux_unix.Client.signal

- **Module:** Libtmux_unix
- **Package:** libtmux-unix
- **Language:** OCaml
- **Kind:** function
- **Source:** https://github.com/libtmux/libtmux-ocaml/blob/205dfda49742592b479247049d186956e4a4cfe9/unix/libtmux_unix.mli#L375
- **Public owner:** Libtmux_unix
- **Page:** https://libtmux.org/en/ocaml/latest/reference/libtmux_unix-client-signal/

```
val signal :
  ?cancel:Cancellation.t -> t -> string -> (unit, Libtmux.Error.t) result
```

Signal a named tmux semaphore, releasing a waiter or retaining the signal for a later [`wait_for`](/en/ocaml/latest/reference/libtmux_unix-client-wait_for/). This does not signal an OS process.

## Parameters

- `cancel?` (`Cancellation.t`)
- `arg1` (`t`)
- `arg2` (`string`)

## tmux command

The tmux commands behind `signal`.

- [`wait-for`](/en/tmux/latest/manual/wait-for/)

## tmux C API

The C declarations in tmux that implement these commands.

- [`cmd_wait_for_entry`](/en/tmux/latest/reference/c-variable-cmd_wait_for_entry/) (attribute)
- [`cmd_wait_for_exec`](/en/tmux/latest/reference/c-function-cmd-wait-for-c-cmd_wait_for_exec/) (function)