# LibTmux::Session#list_windows

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/da7b6191b9439e3c84fa1c9eeaa9168263ee7af4/gems/libtmux/lib/libtmux/entity.rb#L108
- **Page:** https://libtmux.org/en/ruby/v0.1.1/reference/libtmux-session-list_windows/

```
def list_windows: (
  ?timeout: ::Numeric,
  ?cancel: untyped
) -> ::Array[::LibTmux::Window]
```

Behavior: Live acquisition.

Behavior contract: Live acquisition.

## Examples

List all server windows and the windows belonging to one session. 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 `list_windows.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/list_windows.rb).

```ruby
# frozen_string_literal: true

require "libtmux"

begin
  LibTmux::Server.start do |server|
    work = server.new_session(name: "work", command: ["/bin/cat"])
    work.new_window(name: "logs", command: ["/bin/cat"])
    server.new_session(name: "other", command: ["/bin/cat"])
    puts "server windows: #{server.list_windows.length}"
    puts "work windows: #{work.list_windows.length}"
  end
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 list_windows.rb
```

Expected output:

```text
server windows: 3
work windows: 2
```

## Parameters

- `timeout` (`::Numeric`)
- `cancel` (`untyped`)

## tmux command

The tmux commands behind `list_windows`.

- [`list-windows`](/en/tmux/latest/manual/list-windows/) `-t` session scope, [`cmd_list_windows_exec`](/en/tmux/latest/reference/c-function-cmd-list-windows-c-cmd_list_windows_exec/) (source: `gems/libtmux/lib/libtmux/server.rb:470`)

## tmux C API

The C declarations in tmux that implement these commands.

- [`cmd_list_windows_entry`](/en/tmux/latest/reference/c-variable-cmd_list_windows_entry/) (attribute)
- [`cmd_list_windows_exec`](/en/tmux/latest/reference/c-function-cmd-list-windows-c-cmd_list_windows_exec/) (function)

## In other ports

List a session's windows

| Language | Equivalent |
| --- | --- |
| Python | [`libtmux.Session.windows`](/en/py/latest/reference/libtmux-session-windows/) (property) |
| PowerShell | [`LibTmux\Get-TmuxWindow`](/en/powershell/latest/reference/libtmux-get-tmuxwindow/) (cmdlet). Use the [`-Session`](/en/powershell/latest/reference/libtmux-get-tmuxwindow/#LibTmux%5CGet-TmuxWindow.parameter.Session) parameter set to acquire placements in one session. |
| Julia | [`LibTmux.windows`](/en/julia/latest/reference/libtmux-windows/) (function). `windows` with a captured `SessionSnapshot` reads distinct physical windows in that session. Use `windowlinks` for placements. |
| TypeScript | [`session.Session.windows`](/en/ts/latest/reference/session-session-windows/) (method) |
| Rust | [`session.Session.windows`](/en/rs/latest/reference/session-session-windows/) (method) |
| Go | [`tmux.Session.Windows`](/en/go/latest/reference/tmux-session-windows/) (method) |
| Java | [`io.github.libtmux.Session.windows`](/en/java/latest/reference/io-github-libtmux-session-session-windows/) (method) |
| Kotlin | [`io.github.libtmux.kotlin.Session.windows`](/en/kotlin/latest/reference/io-github-libtmux-kotlin-session-windows/) (property) |
| Scala | [`io.github.libtmux.scaladsl.Session.windows`](/en/scala/latest/reference/io-github-libtmux-scaladsl-session-windows/) (method) |
| C# | [`LibTmux.Session.Windows`](/en/csharp/latest/reference/libtmux-session-windows/) (property) |
| F# | [`LibTmux.FSharp.Session.windows`](/en/fsharp/latest/reference/libtmux-fsharp-session-windows/) (function). Builds a deferred window query from one `LibTmux.Session` and its server. `Query.list` acquires placements scoped to that session ID. |
| C++ | [`libtmux::Session::windows`](/en/cxx/latest/reference/libtmux-session-windows/) (method) |
| Swift | [`Snapshot.windows(of:)`](/en/swift/latest/reference/snapshot-windows(of-)/) (method) |

No equivalent is recorded in Lua or Elixir.