1.\" Copyright (c) 1990, 1991, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)bsearch.3 8.3 (Berkeley) 4/19/94 37.\" $FreeBSD: src/lib/libc/stdlib/bsearch.3,v 1.4.2.4 2001/12/14 18:33:58 ru Exp $ 38.\" $DragonFly: src/lib/libc/stdlib/bsearch.3,v 1.2 2003/06/17 04:26:46 dillon Exp $ 39.\" 40.Dd April 19, 1994 41.Dt BSEARCH 3 42.Os 43.Sh NAME 44.Nm bsearch 45.Nd binary search of a sorted table 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In stdlib.h 50.Ft void * 51.Fn bsearch "const void *key" "const void *base" "size_t nmemb" "size_t size" "int (*compar) (const void *, const void *)" 52.Sh DESCRIPTION 53The 54.Fn bsearch 55function searches an array of 56.Fa nmemb 57objects, the initial member of which is 58pointed to by 59.Fa base , 60for a member that matches the object pointed to by 61.Fa key . 62The size of each member of the array is specified by 63.Fa size . 64.Pp 65The contents of the array should be in ascending sorted order according 66to the comparison function referenced by 67.Fa compar . 68The 69.Fa compar 70routine 71is expected to have 72two arguments which point to the 73.Fa key 74object and to an array member, in that order, and should return an integer 75less than, equal to, or greater than zero if the 76.Fa key 77object is found, respectively, to be less than, to match, or be 78greater than the array member. 79.Sh RETURN VALUES 80The 81.Fn bsearch 82function returns a pointer to a matching member of the array, or a null 83pointer if no match is found. 84If two members compare as equal, which member is matched is unspecified. 85.Sh SEE ALSO 86.Xr db 3 , 87.Xr lsearch 3 , 88.Xr qsort 3 89.\" .Xr tsearch 3 90.Sh STANDARDS 91The 92.Fn bsearch 93function conforms to 94.St -isoC . 95