C/C++ Command Line Argument Parser

#include <cargs.h>
#include <stdbool.h>
#include <stdlib.h>

/**
 * This is the main configuration of all options available.
 */
static struct cag_option options[] = {
  {.identifier = 's',
   .access_letters = "s",
   .access_name = NULL,
   .value_name = NULL,
   .description = "Simple flag"},

  {.identifier = 'm',
    .access_letters = "mMoO",
    .access_name = NULL,
    .value_name = NULL,
    .description = "Multiple access letters"},

  {.identifier = 'l',
    .access_letters = NULL,
    .access_name = "long",
    .value_name = NULL,
    .description = "Long parameter name"},

  {.identifier = 'k',
    .access_letters = "k",
    .access_name = "key",
    .value_name = "VALUE",
    .description = "Parameter value"},

  {.identifier = 'h',
    .access_letters = "h",
    .access_name = "help",
    .description = "Shows the command help"}};

/**
 * This is a custom project configuration structure where you can store the
 * parsed information.
 */
struct demo_configuration
{
  bool simple_flag;
  bool multiple_flag;
  bool long_flag;
  const char *key;
};

int main(int argc, char *argv[])
{
  char identifier;
  const char *value;
  cag_option_context context;
  struct demo_configuration config = {false, false, false, NULL};
  int param_index;

  /**
   * Now we just prepare the context and iterate over all options. Simple!
   */
  cag_option_prepare(&context, options, CAG_ARRAY_SIZE(options), argc, argv);
  while (cag_option_fetch(&context)) {
    identifier = cag_option_get(&context);
    switch (identifier) {
    case 's':
      config.simple_flag = true;
      break;
    case 'm':
      config.multiple_flag = true;
      break;
    case 'l':
      config.long_flag = true;
      break;
    case 'k':
      value = cag_option_get_value(&context);
      config.key = value;
      break;
    case 'h':
      printf("Usage: cargsdemo [OPTION]...\n");
      printf("Demonstrates the cargs library.\n\n");
      cag_option_print(options, CAG_ARRAY_SIZE(options), stdout);
      printf("\nNote that all formatting is done by cargs.\n");
      return EXIT_SUCCESS;
    }
  }

  printf("simple_flag: %i, multiple_flag: %i, long_flag: %i, key: %s\n",
    config.simple_flag, config.multiple_flag, config.long_flag,
    config.key ? config.key : "-");

  for (param_index = context.index; param_index < argc; ++param_index) {
    printf("additional parameter: %s\n", argv[param_index]);
  }

  return EXIT_SUCCESS;
}