lsearch(3C)                                                     lsearch(3C)

NAME
     lsearch, lfind - linear search and amendment

SYNOPSIS
     #include <search.h>

     void *lsearch(const void *key, void * base, sizet *nelp,
               sizet width, int (*compar) (const void *, const void *));

     void *lfind(const void *key, const void *base, sizet *nelp,
               sizet width, int (*compar)(const void *, const void *));

DESCRIPTION
     lsearch() is a linear search routine generalized from Knuth (6.1)
     Algorithm S. It returns a pointer into a table indicating where a
     datum was found. If the datum does not occur, it is added at the end
     of the table. key points to the datum to be sought in the table. base
     points to the first element in the table. nelp points to an integer
     containing the current number of elements in the table. The integer is
     incremented if the datum is added to the table. width is the size of
     an element in bytes. compar is a pointer to the comparison function
     that the user must supply (strcmp, for example). Two arguments are
     expected, that point to the elements being compared. The function
     returns 0 if the elements are equal and non-zero otherwise.

     lfind() is the same as lsearch() except that if the datum is not
     found, it is not added to the table. Instead, a null pointer is
     returned.

NOTES
     The pointers to the key and the element at the base of the table may
     be pointers to any type.

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

     The value returned should be cast into type pointer-to-element.

















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lsearch(3C)                                                     lsearch(3C)

EXAMPLE
     The following program will read in less than TABSIZE strings of length
     less than ELSIZE and store them in a table, eliminating duplicates,
     and then will print each entry.

     #include <search.h>
     #include <string.h>
     #include <stdlib.h>
     #include <stdio.h>

     #define TABSIZE 50
     #define ELSIZE 120

       main()
     {
           char line[ELSIZE];      /* buffer to hold input string */
           char tab[TABSIZE][ELSIZE];      /* table of strings */
           sizet nel = 0;         /* number of entries in tab */
           int i;

           while (fgets(line, ELSIZE, stdin) != NULL &&
                   nel < TABSIZE)
                   (void) lsearch(line, tab, &nel, ELSIZE, mycmp);
           for( i = 0; i < nel; i++ )
                   (void)fputs(tab[i], stdout);
           return 0;
     }

NOTES
     If the searched-for datum is found, both lsearch() and lfind() return
     a pointer to it. Otherwise, lfind() returns NULL and lsearch() returns
     a pointer to the newly added element.

     Undefined results can occur if there is not enough room in the table
     to add a new item.

SEE ALSO
     bsearch(3C), hsearch(3C), string(3C), tsearch(3C).
















Page 2                       Reliant UNIX 5.44                Printed 11/98