lsearch(3C)                                           lsearch(3C)



     NAME
          lsearch, lfind - linear search and update

     SYNOPSIS
          #include <stdio.h>
          #include <search.h>

          char *lsearch ((char *)key, (char *)base, nelp, width,
          compar)
          unsigned *nelp, width;
          int (*compar)( );

          char *lfind ((char *)key, (char *)base, nelp, width compar)
          unsigned *nelp, width;
          int (*compar)( );

     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 may be 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 width of an element in bytes; sizeof (*key)
          should be used.  compar is the name of the comparison
          function which the user must supply (strcmp, for example).
          It is called with two arguments that point to the elements
          being compared.  The function must return zero 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 -1 pointer
          is returned.

     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-character.
          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.

     EXAMPLE
          This fragment will read in < TABSIZE strings of length <
          ELSIZE and store them in a table, eliminating duplicates.

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



     Page 1                                        (last mod. 1/14/87)

     lsearch(3C)                                           lsearch(3C)



          #define TABSIZE 50
          #define ELSIZE 120

              char line[ELSIZE], tab[TABSIZE][ELSIZE], *lsearch( );
              unsigned nel = 0;
              int strcmp( );
              . . .
              while (fgets(line, ELSIZE, stdin) != NULL &&
                  nel < TABSIZE)
                    (void) lsearch(line, (char *)tab, &nel,
                           ELSIZE, strcmp);
              . . .

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

     DIAGNOSTICS
          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.

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































     Page 2                                        (last mod. 1/14/87)