dt_Handle molecule;
  dt_String csmi, asmi;
  dt_Integer clen, alen;

  /* Read SMILES in. */
  molecule = dt_smilin(10, "[OH-].[H+]");

  /* Write canonical form. */
  csmi = dt_cansmiles(&clen, molecule, 0);
  /* Write abitrary form. */
  asmi = dt_arbsmiles(&alen, molecule, 0);

  printf("Canonical form is %.*s and arbitrary form is %.*s.\n",
      clen, csmi, alen, asmi);
 
Canonical form is [H+].[OH-] and arbitrary form is [OH-].[H+].