+ * \brief This is a utility function to compute and return a hashcode
+ * for a block of bytes.
+ *
+ * \param key is the start of the block.
+ *
+ * \param n is the byte size of the block.
+ *
+ * \related hashvector
+ */
+extern unsigned long hashvector_hashcode(unsigned char *key,unsigned long n);
+
+/**
+ * \brief Create a \ref hashvector of given \ref vector_variant
+ * for given \ref itemkeyfun.
+ *
+ * \param variant is the \ref vector_variant to use.
+ *
+ * \param type is the \ref itemkeyfun to use.
+ *
+ * \returns the initialised \ref hashvector.
+ *
+ * The hashvector will be initialized with a single \ref vector_page.
+ *
+ * \note The \ref hashvector record is allocated with malloc and the
+ * caller is responsible for free-ing the memory block when it's no
+ * longer needed.