--- /dev/null
+/* to use floats instead of doubles in pf_fold() comment next line */
+#define LARGE_PF
+#ifdef LARGE_PF
+#define FLT_OR_DBL double
+#else
+#define FLT_OR_DBL float
+#endif
+
+extern int noGU; /* GU not allowed at all */
+extern int no_closingGU; /* GU allowed only inside stacks */
+extern int tetra_loop; /* Fold with specially stable 4-loops */
+extern int energy_set; /* 0 = BP; 1=any mit GC; 2=any mit AU-parameter */
+extern int dangles; /* use dangling end energies (not in part_func!) */
+/*@null@*/
+extern char *nonstandards; /* contains allowed non standard bases */
+extern double temperature; /* rescale parameters to this temperature */
+extern int james_rule; /* interior loops of size 2 get energy 0.8Kcal and
+ no mismatches, default 1 */
+extern int logML; /* use logarithmic multiloop energy function */
+extern int cut_point; /* first position of 2nd strand for co-folding */
+
+struct bond { /* base pair */
+ int i;
+ int j;
+};
+typedef struct bond bondT;
+extern bondT *base_pair; /* list of base pairs */
+
+extern FLT_OR_DBL *pr; /* base pairing prob. matrix */
+extern int *iindx; /* pr[i,j] -> pr[iindx[i]-j] */
+extern double pf_scale; /* scaling factor to avoid float overflows*/
+extern int fold_constrained; /* fold with constraints */
+extern int do_backtrack; /* calculate pair prob matrix in part_func() */
+extern int noLonelyPairs; /* avoid helices of length 1 */
+extern char backtrack_type; /* usually 'F'; 'C' require (1,N) to be bonded;
+ 'M' seq is part of a multi loop */
+char * option_string(void);