Double-Linked Lists - Occasional Add Functions

    #include <mplib1/dl_list.h>

    Node_t *Add_Node_After( Node_t *node1, Node_t *node2 );

    Node_t *Add_Node_Before( Node_t *node1, Node_t *node2 );

Add_Node_After adds node2 after node1 in whatever list node1 is.

Add_Node_Before adds node2 before node1 in whatever list node1 is.

Both functions return pointer to node2.