{ "content": [ { "type": "text", "text": "# queue(7) (man)\n\n**Summary:** queue - implementations of linked lists and queues\n\n## See Also\n\n- circleq(3)\n- insque(3)\n- list(3)\n- slist(3)\n- stailq(3)\n- tailq(3)\n\n## Section Outline\n\n- **NAME** (2 lines)\n- **DESCRIPTION** (26 lines) — 6 subsections\n - Singly linked lists (SLIST) (6 lines)\n - Singly linked tail queues (STAILQ) (17 lines)\n - Doubly linked data structures (10 lines)\n - Doubly linked lists (LIST) (10 lines)\n - Doubly linked tail queues (TAILQ) (14 lines)\n - Doubly linked circular queues (CIRCLEQ) (8 lines)\n- **CONFORMING TO** (3 lines)\n- **SEE ALSO** (2 lines)\n- **COLOPHON** (7 lines)\n\n## Full Content\n\n### NAME\n\nqueue - implementations of linked lists and queues\n\n### DESCRIPTION\n\nThe header file provides a set of macros that define and operate on the follow‐\ning data structures:\n\n* singly linked lists (SLIST)\n\n* doubly linked lists (LIST)\n\n* singly linked tail queues (STAILQ)\n\n* doubly linked tail queues (TAILQ)\n\n* doubly linked circular queues (CIRCLEQ)\n\nAll structures support the following functionality:\n\n* Insertion of a new entry at the head of the list.\n\n* Insertion of a new entry after any element in the list.\n\n* O(1) removal of an entry from the head of the list.\n\n* Forward traversal through the list.\n\nCode size and execution time depend on the complexity of the data structure being used, so\nprogrammers should take care to choose the appropriate one.\n\n#### Singly linked lists (SLIST)\n\nSingly linked lists are the simplest and support only the above functionality. Singly linked\nlists are ideal for applications with large datasets and few or no removals, or for imple‐\nmenting a LIFO queue. Singly linked lists add the following functionality:\n\n* O(n) removal of any entry in the list.\n\n#### Singly linked tail queues (STAILQ)\n\nSingly linked tail queues add the following functionality:\n\n* Entries can be added at the end of a list.\n\n* O(n) removal of any entry in the list.\n\n* They may be concatenated.\n\nHowever:\n\n* All list insertions must specify the head of the list.\n\n* Each head entry requires two pointers rather than one.\n\nSingly linked tail queues are ideal for applications with large datasets and few or no re‐\nmovals, or for implementing a FIFO queue.\n\n#### Doubly linked data structures\n\nAll doubly linked types of data structures (lists and tail queues) additionally allow:\n\n* Insertion of a new entry before any element in the list.\n\n* O(1) removal of any entry in the list.\n\nHowever:\n\n* Each element requires two pointers rather than one.\n\n#### Doubly linked lists (LIST)\n\nLinked lists are the simplest of the doubly linked data structures. They add the following\nfunctionality over the above:\n\n* They may be traversed backwards.\n\nHowever:\n\n* To traverse backwards, an entry to begin the traversal and the list in which it is con‐\ntained must be specified.\n\n#### Doubly linked tail queues (TAILQ)\n\nTail queues add the following functionality:\n\n* Entries can be added at the end of a list.\n\n* They may be traversed backwards, from tail to head.\n\n* They may be concatenated.\n\nHowever:\n\n* All list insertions and removals must specify the head of the list.\n\n* Each head entry requires two pointers rather than one.\n\n#### Doubly linked circular queues (CIRCLEQ)\n\nCircular queues add the following functionality over the above:\n\n* The first and last entries are connected.\n\nHowever:\n\n* The termination condition for traversal is more complex.\n\n### CONFORMING TO\n\nNot in POSIX.1, POSIX.1-2001 or POSIX.1-2008. Present on the BSDs. macros\nfirst appeared in 4.4BSD.\n\n### SEE ALSO\n\ncircleq(3), insque(3), list(3), slist(3), stailq(3), tailq(3)\n\n### COLOPHON\n\nThis page is part of release 5.10 of the Linux man-pages project. A description of the\nproject, information about reporting bugs, and the latest version of this page, can be found\nat https://www.kernel.org/doc/man-pages/.\n\n\n\nGNU 2020-11-16 QUEUE(7)\n\n" } ], "structuredContent": { "command": "queue", "section": "7", "mode": "man", "summary": "queue - implementations of linked lists and queues", "synopsis": null, "flags": [], "examples": [], "see_also": [ { "name": "circleq", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/circleq/3/json" }, { "name": "insque", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/insque/3/json" }, { "name": "list", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/list/3/json" }, { "name": "slist", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/slist/3/json" }, { "name": "stailq", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/stailq/3/json" }, { "name": "tailq", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/tailq/3/json" } ], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "DESCRIPTION", "lines": 26, "subsections": [ { "name": "Singly linked lists (SLIST)", "lines": 6 }, { "name": "Singly linked tail queues (STAILQ)", "lines": 17 }, { "name": "Doubly linked data structures", "lines": 10 }, { "name": "Doubly linked lists (LIST)", "lines": 10 }, { "name": "Doubly linked tail queues (TAILQ)", "lines": 14 }, { "name": "Doubly linked circular queues (CIRCLEQ)", "lines": 8 } ] }, { "name": "CONFORMING TO", "lines": 3, "subsections": [] }, { "name": "SEE ALSO", "lines": 2, "subsections": [] }, { "name": "COLOPHON", "lines": 7, "subsections": [] } ] } }