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Welcome to the Fancy Argument Parser wiki!

This is an open-source, single-header library for parsing C++ command-line arguments. It is distributed under the MIT license and follows the philosophy of Python's argparse.

Features:

• single header, zero dependencies — just drop in argparse.h
• named and positional arguments, freely mixed in any order
• typed values (int, long long, double, bool, string)
• flexible arity, including Python-style '?' / '*' / '+'
• validation — choices, numeric ranges, filesystem checks, custom validators
• variable binding — write parsed values straight into your own variables
• pretty, auto-generated help and usage
• optional C++20 module (import argparse;) and keyword-style argument specs
• usable in any project, commercial or open source, without restrictions

The library supports C++11 and later (continuously tested on C++17/20/23 across Linux, macOS and Windows).

Where to go next

• New to argument parsers? Start with the Tutorial.
• Want copy-pasteable recipes? See the Examples.
• On C++20? The C++20 features page covers modules, keyword specs and std::ranges.
• Full API overview: the Class reference.

A zip archive with the class reference is also available. Unzip it and open Documentation/html/index.html.

©simfeo