set *unionSets (set *, set *, int);
set *unionSetsWith (set *, set *, int (*cFunc) (), int);
set *intersectSets (set *, set *, int);
void *addSetIfnotP (set **, void *);
set *setFromSet (set *);
set *unionSets (set *, set *, int);
set *unionSetsWith (set *, set *, int (*cFunc) (), int);
set *intersectSets (set *, set *, int);
void *addSetIfnotP (set **, void *);
set *setFromSet (set *);