On 2/26/07, Sebastian Weber wrote:

On Mon, 2007-02-26 at 10:49 +0100, Tarjei Knapstad wrote:

...

I can't seem to find any documentation on what kind of file formats are accepted when calling boost::program_options::parse_config_file(...)

Am is missing it or is it missing? :)

I think your are right about that missing piece of documentation. However, the format is quite easy:

long-variable-name = value

At least that's how i use it. Hope this helps. Nevertheless, it seems that you can not use unknown variables in your cfg-files.

Greetings,

Sebastian

Is it possible to somehow use an option which selects a configuration file: program --configuration-file my_config.conf with the same easiness as common tasks demonstrated in examples? Thank you. -el

Is it possible to somehow use an option which selects a configuration file:

program --configuration-file my_config.conf

with the same easiness as common tasks demonstrated in examples?

Thank you.

-el

Yes, it's possible, and documented in the "multi-source" section as Sebastian already mentioned. The options_description that is used to parse the command line should contain an option for a configuration file: string configFileName; options_description optdesc("Options"); optdesc.add_options() // add whatever options you have, plus ("config", po::value< string >( &configFileName ), "The name of a file to read for default options. Command-line options" " override the ones in the config file. A config file may contain lines with syntax" "\n'long_option_name = value'\nand comment lines that begin with '#'." ) ; po::store(po::command_line_parser(argc,argv).options(optdesc).positional(popt).run(), varmap); po::notify( varmap ); if( varmap.count("config") ) { cout << "Trying to read options from " << configFileName << "..."; cout.flush(); ifstream ifs( configFileName.c_str() ); if( !ifs.is_open() ) cout << "no such file." << endl; else { po::store( po::parse_config_file( ifs, optdesc ), varmap ); po::notify( varmap ); cout << "done." << endl; } }

Hi!

Thanks Sebastian.

I would consider not allowing unknown variables in a config file to be correct behaviour. (The program should fail if you specify unknown arguments on the command line, and the config file is really just a substitue for the command line options).

Well, I would need this feature quite urgent, because depending upon some parameters, my program loads different objects which have again different program options. Thus I need 2 runs to process all options. In the first run I decide which program modules I have to load. During this first pass, unknown options are no problem so far. Only in the second run, all options have to be processed. Right now I just catch the unknown option exception which works, but leaves me with possibly unparsed program options in the first run. Sebastian

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