lsearch(3C)            UNIX System V(C Development Set)             lsearch(3C)


NAME
      lsearch, lfind - linear search and update

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 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 size of an element in
      bytes. compar is a pointer to the comparison function that 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 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
      compared.

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

EXAMPLE
      This 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()


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lsearch(3C)            UNIX System V(C Development Set)             lsearch(3C)


            {
                  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;
            }

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

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.






























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