# LibTmux::Cancellation#close

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/d8ce4bbee0ca7748a81929f81f7d8d07f8c51267/gems/libtmux/lib/libtmux/process.rb#L68
- **Page:** https://libtmux.org/en/ruby/v0.1.0.alpha.3/reference/libtmux-cancellation-close/

```
def close: () -> void
```

Behavior: Cancellation tokens.

Behavior contract: Cancellation tokens.

## Examples

Wake a blocked request from another thread with a cancellation token and read the delivery evidence on the Cancelled error. Use Ruby 4.0.7, Bundler, Git and tmux 3.3a or newer on Unix, with /bin/cat and /bin/sh available. In an empty directory, fetch the documented library revision:

```console
$ git clone https://github.com/libtmux/libtmux-ruby.git libtmux-source && \
  git -C libtmux-source checkout d8ce4bbee0ca7748a81929f81f7d8d07f8c51267
```

Save this dependency file as Gemfile:

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

gem "libtmux", path: "libtmux-source/gems/libtmux"
```

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/d8ce4bbee0ca7748a81929f81f7d8d07f8c51267/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 runtime dependencies and run the saved program. An operation or cleanup error makes it exit unsuccessfully:

```console
$ bundle config set --local path vendor/bundle && \
  bundle install --jobs 2 && \
  bundle exec ruby cancellation.rb
```

Expected output:

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