catch2/examples/232-Cfg-CustomMain.cpp

//              Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
//   (See accompanying file LICENSE.txt or copy at
//        https://www.boost.org/LICENSE_1_0.txt)

// SPDX-License-Identifier: BSL-1.0

// 232-Cfg-CustomMain.cpp
// Show how to use custom main and add a custom option to the CLI parser

#include <catch2/catch_session.hpp>

#include <iostream>

int main(int argc, char** argv) {
  Catch::Session session; // There must be exactly one instance

  int height = 0; // Some user variable you want to be able to set

  // Build a new parser on top of Catch2's
  using namespace Catch::Clara;
  auto cli
    = session.cli()           // Get Catch2's command line parser
    | Opt( height, "height" ) // bind variable to a new option, with a hint string
         ["--height"]         // the option names it will respond to
         ("how high?");       // description string for the help output

  // Now pass the new composite back to Catch2 so it uses that
  session.cli( cli );

  // Let Catch2 (using Clara) parse the command line
  int returnCode = session.applyCommandLine( argc, argv );
  if( returnCode != 0 ) // Indicates a command line error
      return returnCode;

  // if set on the command line then 'height' is now set at this point
  std::cout << "height: " << height << '\n';

  return session.run();
}