1.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. The name of the author may not be used to endorse or promote products 13.\" derived from this software without specific prior written permission. 14.\" 15.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 16.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 17.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 18.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 21.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 22.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 23.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 24.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" $OpenBSD: tsearch.3,v 1.9 2000/08/09 15:51:21 aaron Exp $ 27.\" 28.Dd June 15, 1997 29.Dt TSEARCH 3 30.Os 31.Sh NAME 32.Nm tsearch , 33.Nm tfind , 34.Nm tdelete , 35.Nm twalk 36.Nd manipulate binary search trees 37.Sh SYNOPSIS 38.Fd #include <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 * const *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 (*action) (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). 56The comparison function passed in by 57the user has the same style of return values as 58.Xr strcmp 3 . 59.Pp 60.Fn tfind 61searches for the datum matched by the argument 62.Fa key 63in the binary tree rooted at 64.Fa rootp , 65returning a pointer to the datum if it is found and 66.Dv NULL 67if it is not. 68.Pp 69.Fn tsearch 70is identical to 71.Fn tfind 72except that if no match is found, 73.Fa key 74is inserted into the tree and a pointer to it is returned. 75If 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 lsearch 3 105.Sh RETURN VALUES 106The 107.Fn tsearch 108function returns 109.Dv NULL 110if allocation of a new node fails (usually 111due to a lack of free memory). 112.Pp 113.Fn tfind , 114.Fn tsearch , 115and 116.Fn tdelete 117return 118.Dv NULL 119if 120.Fa rootp 121is 122.Dv NULL 123or the datum cannot be found. 124.Pp 125The 126.Fn twalk 127function returns no value. 128