Extract some command line args before passing remainder to legacy code

Question

How can one write code so as to fill in the first ellipsis below, so that the legacy code can be given a reduced argument list?:

int main(int argc, char **argv)
         


        

Answer 1

You can try something like this

int main(int argc, char **argv)
{
  std::vector legArgv;
  for(int i = 0; i < argc; ++i) {
      // extract 1 or more optional arguments
      if(isOptional(argv[i])) {
       // ...
      }
      else {
          legArgv.push_back(argv[i]);
      }
  }
  legArgv.push_back(nullptr); // terminate argument vector

  // forward remaining
  LegacyObject leg(legArgv.size(), &(legArgv[0])); 
}