Function ParseCommandLineFlags

paddle/common/flags_native.cc:481–591

TEST_API void AllowUndefinedFlags() { allow_undefined_flags = true; }

TEST_API void ParseCommandLineFlags(int* pargc, char*** pargv) {
  assert(*pargc > 0);
  size_t argv_num = *pargc - 1;
  std::vector<std::string> argvs(*pargv + 1, *pargv + *pargc);

  std::string arg_format_help =
      "please follow the formats: \"--help(h)\", \"--name=value\""
      " or \"--name value\".";
  for (size_t i = 0; i < argv_num; i++) {
    const std::string& argv = argvs[i];

    if (argv.empty()) {
      continue;
    }

    if (argv.size() < 2 || argv[0] != '-') {
      LOG_FLAG_FATAL_ERROR("invalid commandline argument: \"" + argv + "\", " +
                           arg_format_help);
    }

    // parse arg name and value
    size_t hyphen_num = argv[1] == '-' ? 2 : 1;
    std::string name, value;
    size_t split_pos = argv.find('=');
    if (split_pos == std::string::npos) {
      // the argv format is "--name" or "--name value"
      name = argv.substr(hyphen_num);
      if (name.empty()) {
        std::string error_msg = "invalid commandline argument: \"";
        error_msg += argv;
        error_msg += "\", ";
        error_msg += arg_format_help;
        LOG_FLAG_FATAL_ERROR(error_msg);
      }

      // print help message
      if (name == "help" || name == "h") {
        FlagRegistry::Instance()->PrintAllFlagHelp(std::cout);
        exit(1);
      }

      // get the value from next argv.
      if (++i == argv_num) {
        std::string error_msg = "expected value of flag \"";
        error_msg += name;
        error_msg += "\" but found none.";
        LOG_FLAG_FATAL_ERROR(error_msg);
      } else {
        value = argvs[i];
      }
    } else {
      // the argv format is "--name=value"
      if (split_pos == hyphen_num || split_pos == argv.size() - 1) {
        std::string error_msg = "invalid commandline argument: \"";
        error_msg += argv;
        error_msg += "\", ";
        error_msg += arg_format_help;
        LOG_FLAG_FATAL_ERROR(error_msg);