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NSPR Reference Previous Contents Next |
Chapter 21 Linked Lists
Linked List Types
Linked List Macros
Linked List Types
ThePRCList type represents a circular linked list.
PRCList
A circular linked list.Syntax
#include <prclist.h>
typedef struct PRCListStr PRCList;
struct PRCListStr {
PRCList *next;
PRCList *prev;
};
Description
PRClist defines a node in a circular linked list. It can be used as the anchor of a list
and can be embedded in data structures that are maintained in a linked list.
Linked List Macros
Macros that create and operate on linked lists are:
PR_INIT_CLIST
PR_INIT_STATIC_CLIST
PR_APPEND_LINK
PR_INSERT_LINK
PR_NEXT_LINK
PR_PREV_LINK
PR_REMOVE_LINK
PR_REMOVE_AND_INIT_LINK
PR_INSERT_BEFORE
PR_INSERT_AFTER
PR_CLIST_IS_EMPTY
PR_LIST_HEAD
PR_LIST_TAIL
PR_INIT_CLIST
Initializes a circular list.Syntax
#include <prclist.h>
PR_INIT_CLIST (PRCList *listp);
Parameters
The macro has this parameter:
|
listp
|
A pointer to the anchor of the linked list.
|
Description
PR_INIT_CLIST initializes the specified list to be an empty list.
PR_INIT_STATIC_CLIST
Statically initializes a circular list.Syntax
#include <prclist.h>
PR_INIT_STATIC_CLIST (PRCList *listp);
Parameters
The macro has this parameter:
listp
|
A pointer to the anchor of the linked list.
|
Description
PR_INIT_STATIC_CLIST statically initializes the specified list to be an empty list.
For example,
PRCList free_object_list = PR_INIT_STATIC_CLIST(&free_object_list);
PR_APPEND_LINK
Appends an element to the end of a list.Syntax
#include <prclist.h>
PR_APPEND_LINK (
PRCList *elemp,
PRCList *listp);
Parameters
The macro has these parameters:
elemp
|
A pointer to the element to be inserted.
|
listp
|
A pointer to the list.
|
Description
PR_APPEND_LINK adds the specified element to the end of the specified list .
PR_INSERT_LINK
Inserts an element at the head of the list.Syntax
#include <prclist.h>
PR_INSERT_LINK (
PRCList *elemp,
PRCList *listp);
Parameters
The macro has these parameters:
elemp
|
A pointer to the element to be inserted.
|
listp
|
A pointer to the list.
|
Description
PR_INSERT_LINK inserts the specified element at the head of the specified list.
PR_NEXT_LINK
Returns the next element in a list.Syntax
#include <prclist.h>
PRCList *PR_NEXT_LINK (PRCList *elemp);
Parameters
The macro has this parameter:
elemp
|
A pointer to the element.
|
Returns
A pointer to a list element.Description
PR_NEXT_LINK returns a pointer to the element following the specified element. It
can be used to traverse a list. The following element is not removed from the list.
PR_PREV_LINK
Returns the preceding element in a list.Syntax
#include <prclist.h>
PRCList *PR_PREV_LINK (PRCList *elemp);
Parameters
The macro has this parameter:
elemp
|
A pointer to the element.
|
Returns
A pointer to a list element.Description
PR_NEXT_LINK returns a pointer to the element preceding the specified element. It
can be used to traverse a list. The preceding element is not removed from the list.
PR_REMOVE_LINK
Removes an element from a circular list.Syntax
#include <prclist.h>
PR_REMOVE_LINK(PRCList *elemp);
Parameters
The macro has this parameter:
elemp
|
A pointer to the element.
|
Description
PR_REMOVE_LINK removes the specified element from its circular list.
PR_REMOVE_AND_INIT_LINK
Removes an element from a circular list and initializes the linkage.Syntax
#include <prclist.h>
PR_REMOVE_AND_INIT_LINK (PRCList *elemp);
Parameters
The macro has this parameter:
elemp
|
A pointer to the element.
|
Description
PR_REMOVE_AND_INIT_LINK removes the specified element from its circular list
and initializes the links of the element to point to itself.
PR_INSERT_BEFORE
Inserts an element before another element in a circular list.Syntax
#include <prclist.h>
PR_INSERT_BEFORE (
PRCList *elemp1,
PRCList *elemp2);
Parameters
The macro has these parameters:
elemp1
|
A pointer to the element to be inserted.
|
elemp2
|
A pointer to the element before which elemp1 is to be inserted.
|
Description
PR_INSERT_BEFORE inserts the element specified by elemp1 into the circular list,
before the element specified by elemp2.
PR_INSERT_AFTER
Inserts an element after another element in a circular list.Syntax
#include <prclist.h>
PR_INSERT_AFTER (
PRCList *elemp1,
PRCList *elemp2);
Parameters
The macro has these parameters:
elemp1
|
A pointer to the element to be inserted.
|
elemp2
|
A pointer to the element after which elemp1 is to be inserted.
|
Description
PR_INSERT_AFTER the element specified by elemp1 into the circular list, after the
element specified by elemp2.
PR_CLIST_IS_EMPTY
Checks for an empty circular list.Syntax
#include <prclist.h>
PRIntn PR_CLIST_IS_EMPTY (PRCList *listp);
Parameters
The macro has this parameter:
listp
|
A pointer to the linked list.
|
Description
PR_CLIST_IS_EMPTY returns a non-zero value if the specified list is an empty list,
otherwise returns zero.
PR_LIST_HEAD
Returns the head of a circular list.Syntax
#include <prclist.h>
PRCList *PR_LIST_HEAD (PRCList *listp);
Parameters
The macro has this parameter:
listp
|
A pointer to a linked list.
|
Returns
A pointer to a list element.Description
PR_LIST_HEAD returns the head of the specified circular list.
PR_LIST_TAIL
Returns the tail of a circular list.Syntax
#include <prclist.h>
PRCList *PR_LIST_TAIL (PRCList *listp);
Parameters
The macro has this parameter:
listp
|
A pointer to the linked list.
|
Returns
A pointer to a list element.Description
PR_LIST_TAIL returns the tail of the specified circular list.
Last Updated May 18, 2001