boost program_option case insensitive parse of a configuration file

Question

I would like to use boost::program_options to read the options from a configuration file, allowing for a case insensitive parsing.

Consider, e.g., the following simple code:

#include <iostream>
#include <fstream>
#include <string>
#include <boost/program_options/options_description.hpp>
#include <boost/program_options/parsers.hpp>
#include <boost/program_options/variables_map.hpp>

int main()
{
  using namespace std;
  namespace po = boost::program_options;

  ifstream inputfile("input.dat");
  po::options_description desc("");
  desc.add_options()
    ("l", po::value<unsigned int>())
    ;
  po::variables_map vm;
  po::store(po::parse_config_file(inputfile, desc), vm);
  po::notify(vm);

  if (vm.count("l"))
    cout << "l is set as " << vm["l"].as<unsigned int>() << endl;
  else
    cout << "l is not set";

  return 0;
}

With the following input.dat file

l=3

the program runs fine giving output

l is set as 3

If I change the input.dat as

L=3

the program terminates raising an exception

terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::program_options::unknown_option> >'
  what():  unrecognised option 'L'
Aborted

Case-insensitive parsing is apparently possible on the command-line, see the discussion here. Is it possible to have a case-insentive parsing also for reading from a configuration file?

Answer 1

That's not an option.

You can suggest features to the library maintainers.

You can eithr convert the inifile to preferred case using other tools, or add options descriptions for case complements.