function parse() cause unexpected input value changed

[bwlee]

First thanks for your great job.

I got unexpected value changed to input argc.

test code as below:

`

include "cxxopts.hpp"

include

include

using namespace std;

void print_usage(char* n) { std::cout << "usage : " << std::endl; }

static void parse_options(int& argc, char**& argv) { { std::cout << "before parse, input argc : " << argc << ", first argument: " << argv[1] << "...\n"; } cxxopts::Options opt_parser(argv[0]); opt_parser.add_options() ("d,debug", "Enable debug messages from SteamFS", cxxopts::value()) // [...] ("s,single", "Run single-threaded (for testing only)", cxxopts::value());

try {
    auto options = opt_parser.parse(argc, argv);

    if (options.count("help")) {
        print_usage(argv[0]);
        // Strip everything before the option list from the default help string.
        auto help = opt_parser.help();
        std::cout << std::endl << "options:"
                  << help.substr(help.find("\n\n") + 1, string::npos);
        exit(0);

    }
    {
        std::cout << "after parse, input argc : " << argc << ", first argument: " <<  argv[1] << "...\n";
    }
    std::cout << "parsed result:  d: " << options["debug"].as<string>()  << ", s: "<< options["single"].as<int>() << std::endl;

    // Open some files, validate some values, etc
} catch (cxxopts::option_not_exists_exception& exc) {
    std::cout << argv[0] << ": " << exc.what() << std::endl;
    print_usage(argv[0]);
    exit(2);
}

}

int main(int argc, char* argv[]) { std::cout << "argc : " << argc << std::endl; for(int i=0; i < argc; i++) { std::cout << argv[i] << " "; } std::cout<<std::endl; parse_options(argc, argv); return 0; } `

when exec test:

~/w/s/h/c/test ❯❯❯ g++ -o test test.cpp -I ../include/ ~/w/s/h/c/test ❯❯❯ ./test -d sxx -s 3 we can see the input argc changed from 5 to 1.

argc : 5
./test -d sxx -s 3 
before parse, input argc : 5, first argument: -d...
after parse, input argc : 1, first argument: -d...
parsed result:  d: sxx, s: 3

[jarro2783]

That's because cxxopts is removing the arguments that it has recognised. I will be working on a side-effect free version of the parse function at some point in the future.