+/** The callback function used to compare items for insert sort.
+ *
+ * \public \memberof mlt_deque_s
+ * \param a the first object
+ * \param b the second object
+ * \returns 0 if equal, < 0 if a < b, or > 0 if a > b
+*/
+typedef int ( *mlt_deque_compare )( void *a, void *b );
+