---
title: "ClikaRT::cli::App"
sidebar_label: "App"
description: "The application root: a command plus the parse/run entry points, version, help/usage/completion text, and injectable output/error streams. Owns the parser; move-only."
---

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**Header:** `ClikaRT/cli/command.h`  
**Inherits:** [`ClikaRT::cli::Command`](./Command.md)

The application root: a command plus the parse/run entry points, version, help/usage/completion text, and injectable output/error streams. Owns the parser; move-only.

## Member functions

### App(string\_view, string\_view) {#App}

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`explicit` **`App`**(`std::string_view` `program`, `std::string_view` `description` `=` `{}`)

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The root app: [`program`](./App.md#program) is the display name in usage/help; `description` heads the help text.

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Declared in `ClikaRT/cli/command.h`, line 159

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### App(App) {#App-2}

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**`App`**(`App&&`) `noexcept`

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Move-only: transfers the app.

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Declared in `ClikaRT/cli/command.h`, line 161

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### operator=(App) {#operator-assign}

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[`App`](./App.md)`&` **`operator=`**([`App`](./App.md)`&&`) `noexcept`

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Move-assign: transfers the app.

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Declared in `ClikaRT/cli/command.h`, line 163

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### App(App) {#App-3}

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**`App`**(`const App&`) `=delete`

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Declared in `ClikaRT/cli/command.h`, line 164

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### operator=(App) {#operator-assign-2}

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[`App`](./App.md)`&` **`operator=`**(`const` [`App`](./App.md)`&`) `=delete`

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Declared in `ClikaRT/cli/command.h`, line 165

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### \~App() {#App-4}

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**`~App`**()

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Releases the app.

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Declared in `ClikaRT/cli/command.h`, line 167

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### version() {#version}

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[`App`](./App.md)`&` **`version`**(`std::string_view` `v`)

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The text `--`[`version`](./App.md#version) prints; chainable.

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Declared in `ClikaRT/cli/command.h`, line 170

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### allow\_unknown() {#allow_unknown}

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[`App`](./App.md)`&` **`allow_unknown`**(`bool` `v` `=` `true`)

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collect unknown options instead of erroring

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Declared in `ClikaRT/cli/command.h`, line 171

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### wrap\_width() {#wrap_width}

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[`App`](./App.md)`&` **`wrap_width`**(`int` `columns`)

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override the help wrap width

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Declared in `ClikaRT/cli/command.h`, line 172

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### output() {#output}

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[`App`](./App.md)`&` **`output`**(`std::ostream&` `os`)

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where [run()](./App.md#run) prints help/version (default std::cout)

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Declared in `ClikaRT/cli/command.h`, line 173

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### errors() {#errors}

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[`App`](./App.md)`&` **`errors`**(`std::ostream&` `os`)

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where [run()](./App.md#run) prints errors (default std::cerr)

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Declared in `ClikaRT/cli/command.h`, line 174

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### enable\_completion() {#enable_completion}

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[`App`](./App.md)`&` **`enable_completion`**()

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register the hidden `completion <shell>` subcommand

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Declared in `ClikaRT/cli/command.h`, line 175

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### parse() {#parse}

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[`Args`](./Args.md) **`parse`**(`int` `argc`, `const char*const*` `argv`)

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Parse argv; never prints, never exits, never mutates argv. On a usage error returns a failure [`Result`](../Result.md); sets help\_requested()/version\_requested() on the result rather than acting on them.

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Declared in `ClikaRT/cli/command.h`, line 181

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### run() {#run}

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`int` **`run`**(`int` `argc`, `const char*const*` `argv`)

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Parse, then print help/version/errors to the configured streams and dispatch to the matched handler. Returns the handler's exit code, 0 for help/version, or 2 on a usage error. A handler's failure [`Result`](../Result.md), including a throw contained by `detail::contain`, raises [`ClikaRT::Error`](../Error.md) (caller-side, like every fallible call).

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Declared in `ClikaRT/cli/command.h`, line 188

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### help\_text() {#help_text}

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`std::string` **`help_text`**() `const`

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full help for the root command

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Declared in `ClikaRT/cli/command.h`, line 190

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### help\_text(vector\<string\>) {#help_text-2}

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`std::string` **`help_text`**(`const std::vector<std::string>&` `subcommand_path`) `const`

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Full help for the subcommand named by `subcommand_path` (each element the name of a subcommand at the next level down); falls back to root help if the path names no known subcommand.

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Declared in `ClikaRT/cli/command.h`, line 194

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### usage\_line() {#usage_line}

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`std::string` **`usage_line`**() `const`

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the one-line usage synopsis

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Declared in `ClikaRT/cli/command.h`, line 195

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### version\_string() {#version_string}

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`std::string` **`version_string`**() `const`

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the `--`[`version`](./App.md#version) text

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Declared in `ClikaRT/cli/command.h`, line 196

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### completion\_script() {#completion_script}

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`std::string` **`completion_script`**([`Shell`](./index.md#Shell) `shell`) `const`

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A completion script for `shell`; source it in the shell's rc.

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Declared in `ClikaRT/cli/command.h`, line 198

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### program() {#program}

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`std::string_view` **`program`**() `const`

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the program display name

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Declared in `ClikaRT/cli/command.h`, line 199

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