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 1.7 2001/09/07 14:46:36 asmodai Exp $ 29.\" 30.Dd June 15, 1997 31.Dt TSEARCH 3 32.Os 33.Sh NAME 34.Nm tsearch , tfind , tdelete , twalk 35.Nd manipulate binary search trees 36.Sh SYNOPSIS 37.In search.h 38.Ft void * 39.Fn tdelete "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 40.Ft void * 41.Fn tfind "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 42.Ft void * 43.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 44.Ft void 45.Fn twalk "const void *root" "void (*compar) (const void *, VISIT, int)" 46.Sh DESCRIPTION 47The 48.Fn tdelete , 49.Fn tfind , 50.Fn tsearch , 51and 52.Fn twalk 53functions manage binary search trees based on algorithms T and D 54from Knuth (6.2.2). The comparison function passed in by 55the user has the same style of return values as 56.Xr strcmp 3 . 57.Pp 58.Fn Tfind 59searches for the datum matched by the argument 60.Fa key 61in the binary tree rooted at 62.Fa rootp , 63returning a pointer to the datum if it is found and NULL 64if it is not. 65.Pp 66.Fn Tsearch 67is identical to 68.Fn tfind 69except that if no match is found, 70.Fa key 71is inserted into the tree and a pointer to it is returned. If 72.Fa rootp 73points to a NULL value a new binary search tree is created. 74.Pp 75.Fn Tdelete 76deletes a node from the specified binary search tree and returns 77a pointer to the parent of the node to be deleted. 78It takes the same arguments as 79.Fn tfind 80and 81.Fn tsearch . 82If the node to be deleted is the root of the binary search tree, 83.Fa rootp 84will be adjusted. 85.Pp 86.Fn Twalk 87walks the binary search tree rooted in 88.Fa root 89and calls the function 90.Fa action 91on each node. 92.Fa Action 93is called with three arguments: a pointer to the current node, 94a value from the enum 95.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 96specifying the traversal type, and a node level (where level 97zero is the root of the tree). 98.Sh SEE ALSO 99.Xr bsearch 3 , 100.Xr hsearch 3 , 101.Xr lsearch 3 102.Sh RETURN VALUES 103The 104.Fn tsearch 105function returns NULL if allocation of a new node fails (usually 106due to a lack of free memory). 107.Pp 108.Fn Tfind , 109.Fn tsearch , 110and 111.Fn tdelete 112return NULL if 113.Fa rootp 114is NULL or the datum cannot be found. 115.Pp 116The 117.Fn twalk 118function returns no value. 119
