Re: [Boost-users] program_options: iterate variable_map

From: François Duranleau (duranlef_at_[hidden])
Date: 2006-04-06 13:09:20

On Wed, 5 Apr 2006, Andrew Schweitzer wrote:

> Stephan Stiglmayr wrote:
>>
>> I'm looking for a way to "iterate" through a variable_map after the
>> command line options were stored, in order to print out all the options,
>> or all with newly values.
[...]
>> I know that you can test if a specific options was read with the
>> "count()" method, but this is cumbersome.
[...]
>> Is there a possiblity to do that?
>
> I wrote a wrapper class that adds options to a list as they are added to
> program_options, then you can print the list. This is a hack.

Also, another 'hack' is that, looking in the code, you can notice that 
variables_map inherits from std::map as well (though it's not documented 
as such). You can thus use standard STL iterators, e.g.

for ( variables_map::iterator i = vm.begin() ; i != vm.end() ; ++ i )
{
    //...
}

The type of values iterated over are pairs of std::string and 
boost::program_options::variable_value.

-- 
François Duranleau
LIGUM, Université de Montréal
"You only think you understand. But people cannot perfectly understand
  each other. The self is an ambiguous thing."
                                       - Kaji, in _Neon Genesis Evangelion_