--- /dev/null
+#ifndef PKPLEX_H
+#define PKPLEX_H
+
+#include "data_structures.h"
+
+extern dupVar *PlexHits;
+extern int PlexHitsArrayLength;
+extern int NumberOfHits;
+extern int verbose;
+
+
+/**
+ * \brief
+ */
+dupVar **PKLduplexfold_XS( const char *s1,
+ int **access_s1,
+ const int threshold,
+ const int alignment_length,
+ const int delta);
+
+int arraySize(duplexT **array);
+
+void freeDuplexT(duplexT **array);
+
+#endif