insque(3C)

insque, remque -- insert/remove element from a queue

Synopsis

   
   include <search.h>
   

   extern void insque(void element, void pred);
   

   extern void remque(void element);

Description

insque and remque manipulate queues built from doubly linked lists. The queue can be either circular or linear. The application must define a structure in which the first two members of the structure are pointers to the same type of structure, and any further members are application-specific. The first member points forward to the next entry, the second points back to the previous entry. A linear queue is terminated with null pointers.

insque inserts element in a queue immediately after pred. remque removes an entry element from a queue.

If the queue is to be used as a linear list, invoking insque(&element, NULL, where element is the initial element of the queue, will initialize the forward and backward pointers of element to null pointers.

If the queue is to be used as a circular list, the application must initialize the forward and backward pointers of the initial queue element to the element's address.

Notices

It is the caller's responsibility never to insert or delete a member before the first member of the list or after the last member of the list. The first and last members of the list must remain in place for the duration of the use of the list.