# LibTmux::Server#wait_for

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/da7b6191b9439e3c84fa1c9eeaa9168263ee7af4/gems/libtmux/lib/libtmux/operations.rb#L47
- **Page:** https://libtmux.org/en/ruby/v0.1.1/reference/libtmux-server-wait_for/

```
def wait_for: (
  ::String,
  ?action: :wait | :signal | :lock | :unlock,
  ?timeout: ::Numeric,
  ?cancel: untyped
) -> ::LibTmux::CommandResult
```

Retiring the client cannot remove a dispatched waiter from tmux's queue.

Behavior contract: Wait channels.

## Examples

Wake a blocked request from another thread with a cancellation token and read the delivery evidence on the Cancelled error. Use Ruby 3.3 or newer with Bundler, and tmux 3.3a or newer, on Unix with `/bin/cat` and `/bin/sh` available. In an empty directory, save this `Gemfile`:

```ruby
source "https://rubygems.org"

gem "libtmux", "0.1.1"
```

Save this complete program as `cancellation.rb`. Its `Server.start` block owns a private tmux server and stops it on exit, including after an error.

[Source example](https://github.com/libtmux/libtmux-ruby/blob/da7b6191b9439e3c84fa1c9eeaa9168263ee7af4/examples/api/cancellation.rb).

```ruby
# frozen_string_literal: true

begin
  # docs:begin main
  require "libtmux"

  LibTmux::Server.start do |server|
    server.new_session(name: "work", command: ["/bin/cat"])
    cancellation = LibTmux::Cancellation.new
    waiting = Thread.new do
      server.run(["wait-for", "-S", "ready", ";", "wait-for", "held"], timeout: 5, cancel: cancellation)
    rescue LibTmux::Cancelled => error
      error
    end
    server.wait_for("ready", timeout: 5)
    cancellation.cancel
    failure = waiting.value
    puts "request: #{failure.class}"
    puts "delivery: #{failure.delivery}"
    cancellation.close
  end
  # docs:end main
rescue StandardError => error
  warn "#{error.class}: #{error.message}"
  exit 1
end
```

Install the gem and run the program. An operation or cleanup error makes it exit unsuccessfully:

```console
$ bundle install && \
  bundle exec ruby cancellation.rb
```

Expected output:

```text
request: LibTmux::Cancelled
delivery: possibly_sent
```

## Parameters

- `arg1` (`::String`)
- `action` (`:wait | :signal | :lock | :unlock`)
- `timeout` (`::Numeric`)
- `cancel` (`untyped`)

## tmux command

The tmux commands behind `wait_for`.

- [`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)

## In other ports

Wait for, signal or lock a channel

| Language | Equivalent |
| --- | --- |
| Python | [`libtmux.Server.wait_for`](/en/py/latest/reference/libtmux-server-wait_for/) (method) |
| TypeScript | no equivalent on `Server` |
| Rust | [`server.Server.wait_for_channel`](/en/rs/latest/reference/server-server-wait_for_channel/) (method) |
| Go | [`tmux.Server.WaitFor`](/en/go/latest/reference/tmux-server-waitfor/) (method) |
| Java | no equivalent on `Server` |
| C# | [`LibTmux.Server.WaitForAsync`](/en/csharp/latest/reference/libtmux-server-waitforasync/) (method) |
| C++ | [`libtmux::Server::wait_for`](/en/cxx/latest/reference/libtmux-server-wait_for/) (method) |
| Swift | [`Server.wait(for:)`](/en/swift/latest/reference/server-wait(for-)/) (method) |

No equivalent is recorded in Lua, PowerShell, Julia, Elixir, Kotlin, Scala or F#.