enum options {    OPT_ZERO,                   /* must be 0 */    OPT_HELP,    OPT_MESH_FILE,    OPT_RAY_FILE,    OPT_BUNDLE_FILE,    OPT_SCO_FILE,    OPT_VERSION};const struct poptOption options[] = {    /* long optin,short option, type,var,default val,explanation,expl 2 */    {     "help", 'h', POPT_ARG_NONE,     NULL, OPT_HELP,     "help", "display this help message"},    {     "mesh", 'm', POPT_ARG_STRING,     &mesh_file_opt, OPT_MESH_FILE,     "mesh config file (xml)", "FILE"},    {     "ray", 'i', POPT_ARG_STRING,     &ray_file_opt, OPT_RAY_FILE,     "ray input data", "FILE"},    {     "bundle", 'o', POPT_ARG_STRING,     &bundle_file_opt, OPT_BUNDLE_FILE,     "output file with ray bundle", "FILE"},    {     "sco", 's', POPT_ARG_STRING,     &sco_file_opt, OPT_SCO_FILE,     "sco output file (nb of bundle per cell)", "FILE"},   {     "version", 'v', POPT_ARG_NONE,     NULL, OPT_VERSION,     "Print version number", NULL},    {NULL, '\0', 0, NULL, OPT_ZERO, NULL, NULL}};