1.\" $NetBSD$ 2.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 17.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 18.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 19.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" OpenBSD: tsearch.3,v 1.2 1998/06/21 22:13:49 millert Exp 28.\" $FreeBSD: src/lib/libc/stdlib/tsearch.3,v 1.1.2.6 2001/12/14 18:33:58 ru Exp $ 29.\" $DragonFly: src/lib/libc/stdlib/tsearch.3,v 1.2 2003/06/17 04:26:46 dillon Exp $ 30.\" 31.Dd June 15, 1997 32.Dt TSEARCH 3 33.Os 34.Sh NAME 35.Nm tsearch , tfind , tdelete , twalk 36.Nd manipulate binary search trees 37.Sh SYNOPSIS 38.In search.h 39.Ft void * 40.Fn tdelete "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 41.Ft void * 42.Fn tfind "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 43.Ft void * 44.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 45.Ft void 46.Fn twalk "const void *root" "void (*compar) (const void *, VISIT, int)" 47.Sh DESCRIPTION 48The 49.Fn tdelete , 50.Fn tfind , 51.Fn tsearch , 52and 53.Fn twalk 54functions manage binary search trees based on algorithms T and D 55from Knuth (6.2.2). The comparison function passed in by 56the user has the same style of return values as 57.Xr strcmp 3 . 58.Pp 59.Fn Tfind 60searches for the datum matched by the argument 61.Fa key 62in the binary tree rooted at 63.Fa rootp , 64returning a pointer to the datum if it is found and NULL 65if it is not. 66.Pp 67.Fn Tsearch 68is identical to 69.Fn tfind 70except that if no match is found, 71.Fa key 72is inserted into the tree and a pointer to it is returned. If 73.Fa rootp 74points to a NULL value a new binary search tree is created. 75.Pp 76.Fn Tdelete 77deletes a node from the specified binary search tree and returns 78a pointer to the parent of the node to be deleted. 79It takes the same arguments as 80.Fn tfind 81and 82.Fn tsearch . 83If the node to be deleted is the root of the binary search tree, 84.Fa rootp 85will be adjusted. 86.Pp 87.Fn Twalk 88walks the binary search tree rooted in 89.Fa root 90and calls the function 91.Fa action 92on each node. 93.Fa Action 94is called with three arguments: a pointer to the current node, 95a value from the enum 96.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 97specifying the traversal type, and a node level (where level 98zero is the root of the tree). 99.Sh SEE ALSO 100.Xr bsearch 3 , 101.Xr hsearch 3 , 102.Xr lsearch 3 103.Sh RETURN VALUES 104The 105.Fn tsearch 106function returns NULL if allocation of a new node fails (usually 107due to a lack of free memory). 108.Pp 109.Fn Tfind , 110.Fn tsearch , 111and 112.Fn tdelete 113return NULL if 114.Fa rootp 115is NULL or the datum cannot be found. 116.Pp 117The 118.Fn twalk 119function returns no value. 120