[Boost-users] [program_options] VM object unable to store the values of options

Subject: [Boost-users] [program_options] VM object unable to store the values of options
From: Wenjing Jia (wejia_at_[hidden])
Date: 2009-02-05 18:47:20

(Apologies if this message has come out for more than once, as I had 
problem with authorization and is unsure when the message is able to be 
seen by boost users!)

Hi,

I'm met a very weird thing when using the “Boost.Program_options” 
library. Somehow, the variable-map(VM) object is unable to store values 
of options which are fed in from the command line. I've been stuck in 
this stupid problem for two days and cannot find any clue about it. Can 
someone please give me a hint?

I'm using the Visual Studio 2005 on Windows XP SP3 to compile some 
examples provided in Boost.Program_options Tutorial. The boost library 
was installed using the boost_1_34_1 installer. However, no matter what 
value I input to any option, the variable-map object "vm" I defined is 
unable to store it and output it correctly.

For instance, I followed the instructions in the Tutorial of the 
Boost.Program_options and compiled the first simplest possible example 
"example/first.cpp". I then went to "start" of Windows XP and Run "cmd", 
then run: "first --compression 10". The output is always "Compression 
level was set to -858993460." regardless of what value I type after the 
"--compression". Below is the full codes of the program (copied from the 
"example/first.cpp"):
-------------------------------------------------------------------------------
#include <boost/program_options.hpp>
namespace po = boost::program_options;

#include <iostream>
#include <iterator>
using namespace std;

int main(int ac, char* av[])
{
     try {
         po::options_description desc("Allowed options");
         desc.add_options()
             ("help", "produce help message")
             ("compression", po::value<int>(), "set compression level")
         ;

         po::variables_map vm;
         po::store(po::parse_command_line(ac, av, desc), vm);
         po::notify(vm);

         if (vm.count("help")) {
             cout << desc << "\n";
             return 1;
         }

         if (vm.count("compression")) {
             cout << "Compression level was set to "
                  << vm["compression"].as<int>() << ".\n";
         } else {
             cout << "Compression level was not set.\n";
         }
     }
     catch(exception& e) {
         cerr << "error: " << e.what() << "\n";
         return 1;
     }
     catch(...) {
         cerr << "Exception of unknown type!\n";
     }

     return 0;
}
-------------------------------------------------------------------------------

I also tried on the other examples mentioned on that web page, such as 
"example/options_description.cpp". When I type:
"options_description --optimization 4 -I foo a.cpp",
the output is:
"Include paths are:
Input files are:
Optimization level is -858993460".
That is the input values are not taken and stored by the vm object.

Why such a simple example won't work on my machine!?
Your suggestion would be most appreciated!

Many thanks in advance!
Wenjing