--- /dev/null
+/* function from fold.c */
+extern float fold(const char *sequence, char *structure);
+/* calculate mfe-structure of sequence */
+extern float energy_of_struct(const char *string, const char *structure);
+/* calculate energy of string on structure */
+extern void free_arrays(void); /* free arrays for mfe folding */
+extern void initialize_fold(int length); /* allocate arrays for folding */
+extern void update_fold_params(void); /* recalculate parameters */