# LibTmux::Cancellation.new

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/da7b6191b9439e3c84fa1c9eeaa9168263ee7af4/gems/libtmux/lib/libtmux/process.rb#L46
- **Page:** https://libtmux.org/en/ruby/v0.1.1/reference/libtmux-cancellation-new/

```
def self.new: () -> ::LibTmux::Cancellation
```

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 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
```

## Guides

Pages that discuss `new`.

- [Ownership and errors](/en/ruby/v0.1.1/topics/errors-and-exceptions/)