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.\" $FreeBSD$ 38.\" 39.Dd April 19, 1994 40.Dt BSEARCH 3 41.Os 42.Sh NAME 43.Nm bsearch 44.Nd binary search of a sorted table 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In stdlib.h 49.Ft void * 50.Fn bsearch "const void *key" "const void *base" "size_t nmemb" "size_t size" "int (*compar) (const void *, const void *)" 51.Sh DESCRIPTION 52The 53.Fn bsearch 54function searches an array of 55.Fa nmemb 56objects, the initial member of which is 57pointed to by 58.Fa base , 59for a member that matches the object pointed to by 60.Fa key . 61The size of each member of the array is specified by 62.Fa size . 63.Pp 64The contents of the array should be in ascending sorted order according 65to the comparison function referenced by 66.Fa compar . 67The 68.Fa compar 69routine 70is expected to have 71two arguments which point to the 72.Fa key 73object and to an array member, in that order, and should return an integer 74less than, equal to, or greater than zero if the 75.Fa key 76object is found, respectively, to be less than, to match, or be 77greater than the array member. 78.Sh RETURN VALUES 79The 80.Fn bsearch 81function returns a pointer to a matching member of the array, or a null 82pointer if no match is found. 83If two members compare as equal, which member is matched is unspecified. 84.Sh SEE ALSO 85.Xr db 3 , 86.Xr lsearch 3 , 87.Xr qsort 3 88.\" .Xr tsearch 3 89.Sh STANDARDS 90The 91.Fn bsearch 92function conforms to 93.St -isoC . 94