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 1.5 2007/08/18 20:48:47 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 LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In search.h 44.Ft void * 45.Fn tdelete "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 46.Ft void * 47.Fn tfind "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 48.Ft void * 49.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 50.Ft void 51.Fn twalk "const void *root" "void (*compar) (const void *, VISIT, int)" 52.Sh DESCRIPTION 53The 54.Fn tdelete , 55.Fn tfind , 56.Fn tsearch , 57and 58.Fn twalk 59functions manage binary search trees based on algorithms T and D 60from Knuth (6.2.2). The comparison function passed in by 61the user has the same style of return values as 62.Xr strcmp 3 . 63.Pp 64.Fn Tfind 65searches for the datum matched by the argument 66.Fa key 67in the binary tree rooted at 68.Fa rootp , 69returning a pointer to the datum if it is found and NULL 70if it is not. 71.Pp 72.Fn Tsearch 73is identical to 74.Fn tfind 75except that if no match is found, 76.Fa key 77is inserted into the tree and a pointer to it is returned. If 78.Fa rootp 79points to a NULL value a new binary search tree is created. 80.Pp 81.Fn Tdelete 82deletes a node from the specified binary search tree and returns 83a pointer to the parent of the node to be deleted. 84It takes the same arguments as 85.Fn tfind 86and 87.Fn tsearch . 88If the node to be deleted is the root of the binary search tree, 89.Fa rootp 90will be adjusted. 91.Pp 92.Fn Twalk 93walks the binary search tree rooted in 94.Fa root 95and calls the function 96.Fa action 97on each node. 98.Fa Action 99is called with three arguments: a pointer to the current node, 100a value from the enum 101.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 102specifying the traversal type, and a node level (where level 103zero is the root of the tree). 104.Sh RETURN VALUES 105The 106.Fn tsearch 107function returns NULL if allocation of a new node fails (usually 108due to a lack of free memory). 109.Pp 110.Fn Tfind , 111.Fn tsearch , 112and 113.Fn tdelete 114return NULL if 115.Fa rootp 116is NULL or the datum cannot be found. 117.Pp 118The 119.Fn twalk 120function returns no value. 121.Sh SEE ALSO 122.Xr bsearch 3 , 123.Xr hsearch 3 , 124.Xr lsearch 3 125