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.\" %sccs.include.redist.man% 9.\" 10.\" @(#)bsearch.3 8.3 (Berkeley) 04/19/94 11.\" 12.Dd 13.Dt BSEARCH 3 14.Os 15.Sh NAME 16.Nm bsearch 17.Nd binary search of a sorted table 18.Sh SYNOPSIS 19.Fd #include <stdlib.h> 20.Ft void * 21.Fn bsearch "const void *key" "const void *base" "size_t nmemb" "size_t size" "int (*compar) (const void *, const void *)" 22.Sh DESCRIPTION 23The 24.Fn bsearch 25function searches an array of 26.Fa nmemb 27objects, the initial member of which is 28pointed to by 29.Fa base , 30for a member that matches the object pointed to by 31.Fa key . 32The size of each member of the array is specified by 33.Fa size . 34.Pp 35The contents of the array should be in ascending sorted order according 36to the comparison function referenced by 37.Fa compar . 38The 39.Fa compar 40routine 41is expected to have 42two arguments which point to the 43.Fa key 44object and to an array member, in that order, and should return an integer 45less than, equal to, or greater than zero if the 46.Fa key 47object is found, respectively, to be less than, to match, or be 48greater than the array member. 49.Sh RETURN VALUES 50The 51.Fn bsearch 52function returns a pointer to a matching member of the array, or a null 53pointer if no match is found. 54If two members compare as equal, which member is matched is unspecified. 55.Sh SEE ALSO 56.Xr db 3 , 57.Xr lsearch 3 , 58.Xr qsort 3 , 59.\" .Xr tsearch 3 60.Sh STANDARDS 61The 62.Fn bsearch 63function conforms to 64.St -ansiC . 65