i read lib boost in http://www.boost.org/doc/libs/1_42_0.../file_size.cpp then build on QTCreator but it error,can you help Me debug source ?


Qt Code: 
  1. #include <boost/filesystem/operations.hpp>
  2. #include <iostream>
  3. namespace fs = boost::filesystem;
  4. int main( int argc, char* argv[] )
  5. {
  6.   if ( argc != 2 )
  7.   {
  8.     std::cout << "Usage: file_size path\n";
  9.     return 1;
  10.   }
  11.   std::cout << "sizeof(intmax_t) is " << sizeof(boost::intmax_t) << '\n';
  12.   fs::path p( argv[1], fs::native );
  13.  
  14.   if ( !fs::exists( p ) )
  15.   {
  16.     std::cout << "not found: " << argv[1] << std::endl;
  17.     return 1;
  18.   }
  19.   if ( !fs::is_regular( p ) )
  20.   {
  21.     std::cout << "not a regular file: " << argv[1] << std::endl;
  22.     return 1;
  23.   }
  24.   std::cout << "size of " << argv[1] << " is " << fs::file_size( p )
  25.     << std::endl;
  26.   return 0;
  27. }
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**/boost_1_42_0/boost/system/error_code.hpp:208: undefined reference to `boost::system::get_system_category()'**


my source code
http://www.mediafire.com/?inzzmlwwm4w