Excess positional arguments do not generate an error.

[agoessling]

If excess positional arguments are provided the parser does not raise an exception.

struct FileOptions {
  // Positional arguments
  // ./main <input_file> <output_file>
  std::string input_file;
  std::string output_file;
};
STRUCTOPT(FileOptions, input_file, output_file);

Executing ./main file1 file2 file3 does not raise an exception.