Re: [boost] program options (consider using BOOST_THROW_EXCEPTION)

Subject: Re: [boost] program options (consider using BOOST_THROW_EXCEPTION)
From: Roger Martin (roger_at_[hidden])
Date: 2012-06-27 17:12:56

On 06/27/2012 04:51 PM, Emil Dotchevski wrote:
> On Wed, Jun 27, 2012 at 4:46 AM, Leo Goodstadt<leo.goodstadt_at_[hidden]>wrote:
>
>> However, the majority of exceptions in program_options are there to
>> indicate a problem in the construction of the command line by the
>> *end-user* (not the programmer).
>> In other words, the program *is* working exactly as designed.
>
> Unless it's buggy.
>
> The
>> programmer has no interest in the provenance of these exceptions
>> *except* that they can be used to inform the end-user how they should
>> retype the command line and try again.
>>
> The use case is this:
>
> int main( int argc, char const * argv[] )
> {
>    try
>    {
>      do_work(parse_command_line(argc,argv));
>    }
>    catch( X&  )
>    {
>    }
>    catch( Y&  )
>    {
>    }
>    catch(...)
>    {
>      std::cerr<<  boost::current_exception_diagnostic_information();
>      abort();
>    }
> }
>
> The catch(...) shouldn't be reached. The BOOST_THROW_EXCEPTION information
> could help if it is (of course the message is intended for the programmer,
> not the end user.)
Hi, when I first asked about this I wasn't comprehending the nature of 
it being exceptions for the user but that makes complete sense. So from 
your advice I'm planning to tee off the information to a DEBUG level 
logger for the developer (untested):
     catch( boost::program_options::unknown_option & e )
     {
         std::cout << "Command line incorrect: unknown option 
"<<e.get_option_name();
         std::cout.flush();
         std::cout << "\n" << desc << "\n";
         LOG4CPLUS_DEBUG(logger, boost::diagnostic_information(e));
      }

This way a user sees the friendlier message yet if there is some 
sleuthing to do, a developer or remote user  may configure the runtime 
log level and get the more detailed information that way
>
> Emil Dotchevski
> Reverge Studios, Inc.
> http://www.revergestudios.com/reblog/index.php?n=ReCode
>
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