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 1.3 2005/08/05 22:35:10 swildner Exp $ 30.\" 31.Dd June 15, 1997 32.Dt TSEARCH 3 33.Os 34.Sh NAME 35.Nm tsearch , 36.Nm tfind , 37.Nm tdelete , 38.Nm twalk 39.Nd manipulate binary search trees 40.Sh SYNOPSIS 41.In search.h 42.Ft void * 43.Fn tdelete "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 44.Ft void * 45.Fn tfind "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 46.Ft void * 47.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 48.Ft void 49.Fn twalk "const void *root" "void (*compar) (const void *, VISIT, int)" 50.Sh DESCRIPTION 51The 52.Fn tdelete , 53.Fn tfind , 54.Fn tsearch , 55and 56.Fn twalk 57functions manage binary search trees based on algorithms T and D 58from Knuth (6.2.2). The comparison function passed in by 59the user has the same style of return values as 60.Xr strcmp 3 . 61.Pp 62.Fn Tfind 63searches for the datum matched by the argument 64.Fa key 65in the binary tree rooted at 66.Fa rootp , 67returning a pointer to the datum if it is found and NULL 68if it is not. 69.Pp 70.Fn Tsearch 71is identical to 72.Fn tfind 73except that if no match is found, 74.Fa key 75is inserted into the tree and a pointer to it is returned. If 76.Fa rootp 77points to a NULL value a new binary search tree is created. 78.Pp 79.Fn Tdelete 80deletes a node from the specified binary search tree and returns 81a pointer to the parent of the node to be deleted. 82It takes the same arguments as 83.Fn tfind 84and 85.Fn tsearch . 86If the node to be deleted is the root of the binary search tree, 87.Fa rootp 88will be adjusted. 89.Pp 90.Fn Twalk 91walks the binary search tree rooted in 92.Fa root 93and calls the function 94.Fa action 95on each node. 96.Fa Action 97is called with three arguments: a pointer to the current node, 98a value from the enum 99.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 100specifying the traversal type, and a node level (where level 101zero is the root of the tree). 102.Sh SEE ALSO 103.Xr bsearch 3 , 104.Xr hsearch 3 , 105.Xr lsearch 3 106.Sh RETURN VALUES 107The 108.Fn tsearch 109function returns NULL if allocation of a new node fails (usually 110due to a lack of free memory). 111.Pp 112.Fn Tfind , 113.Fn tsearch , 114and 115.Fn tdelete 116return NULL if 117.Fa rootp 118is NULL or the datum cannot be found. 119.Pp 120The 121.Fn twalk 122function returns no value. 123