ultrix man page for bsearch

bsearch(3)						     Library Functions Manual							bsearch(3)

Name
       bsearch - binary search a sorted table

Syntax
       #include <stdlib.h>

       void *bsearch (key, base, nel, sizeof (*key), compar)
       void *key, *base;
       size_t nel;
       int (*compar)( );

Description
       The subroutine is a binary search routine generalized from Knuth (6.2.1) Algorithm B.  It returns a pointer into a table indicating where a
       datum may be found.  The table must be previously sorted in increasing order according to a provided comparison function.  The  key  points
       to the datum to be sought in the table.	The base points to the element at the base of the table.  The nel is the number of elements in the
       table.  The compar is the name of the comparison function, which is called with two arguments that point to the	elements  being  compared.
       The  function  must return an integer less than, equal to, or greater than zero according to whether the first argument is to be considered
       less than, equal to, or greater than the second.

Diagnostics
       A NULL pointer is returned if the key cannot be found in the table.

   Notes
       The pointers to the key and the element at the base of the table should be of type pointer-to-element, and cast to type	pointer-to-charac-
       ter.

       The  comparison	function  need	not compare every byte, so arbitrary data may be contained in the elements in addition to the values being
       compared.

       Although declared as type pointer-to-character, the value returned should be cast into type pointer-to-element.

See Also
       hsearch(3), lsearch(3), qsort(3), tsearch(3)

																	bsearch(3)