Recherche de la Xieme occurence d'un mot dans un std::string

struct info {
  char * nom;
  char * origine;
  char * usage;
};

void
parse_info(char * line, struct info * inf)
{
  char * tab = strchr(line, '\t');
  if (tab == NULL)
    goto err_nom;
  *tab = 0;
  inf->nom = strdup(line);
  line = tab + 1;
  tab = strchr(line, '\t');
  if (tab == NULL)
    goto err_origine;
  *tab = 0;
  inf->origine = strdup(line);
  line = tab + 1;
  inf->usage = strdup(line);
  return;
err_nom:
  inf->nom = strdup("");
err_origine:
  inf->origine = strdup("");
  inf->usage = strdup("");
}