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. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" $OpenBSD: bsearch.3,v 1.10 2015/11/30 17:03:05 jmc Exp $ 33.\" 34.Dd $Mdocdate: November 30 2015 $ 35.Dt BSEARCH 3 36.Os 37.Sh NAME 38.Nm bsearch 39.Nd binary search of a sorted table 40.Sh SYNOPSIS 41.In stdlib.h 42.Ft void * 43.Fn bsearch "const void *key" "const void *base" "size_t nmemb" "size_t size" "int (*compar)(const void *, const void *)" 44.Sh DESCRIPTION 45The 46.Fn bsearch 47function searches an array of 48.Fa nmemb 49objects, the initial member of which is 50pointed to by 51.Fa base , 52for a member that matches the object pointed to by 53.Fa key . 54The size of each member of the array is specified by 55.Fa size . 56.Pp 57The contents of the array should be in ascending sorted order according 58to the comparison function referenced by 59.Fa compar . 60The 61.Fa compar 62routine is expected to have two arguments which point to the 63.Fa key 64object and to an array member, in that order, and should return an integer 65less than, equal to, or greater than zero if the 66.Fa key 67object is found, respectively, to be less than, to match, or be 68greater than the array member. 69.Sh RETURN VALUES 70The 71.Fn bsearch 72function returns a pointer to a matching member of the array, or a null 73pointer if no match is found. 74If two members compare as equal, which member is matched is unspecified. 75.Sh SEE ALSO 76.Xr dbopen 3 , 77.Xr lsearch 3 , 78.Xr qsort 3 , 79.Xr tsearch 3 80.Sh STANDARDS 81The 82.Fn bsearch 83function conforms to 84.St -ansiC . 85