qsort(3C)                                               qsort(3C)



NAME
     qsort - performs a quicker sort

SYNOPSIS
     void qsort(base, nel, width, compar)
     char *base;
     unsigned nel, width;
     int(*compar)();

DESCRIPTION
     qsort is an implementation of the quicker-sort algorithm.
     It sorts a table of data in place.

     base points to the element at the base of the table.  nel is
     the number of elements in the table.  width is the width of
     an element in bytes.  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 if the
     first argument is to be considered less than, equal to, or
     greater than the second.

EXAMPLES
        struct  entry {
                char    *name;
                int     flags;
        };

        main()
        {
                struct entry hp[100];
                int entcmp();
                int i, count;

                for (i = 0; i < (count = 100); i++) {
                        /* fill the structure with the name
                           and flags */
             ...
                }
                qsort( (char *) hp, count, sizeof (hp[0]), entcmp);
        }

        entcmp(ep,ep2)
        struct entry *ep, *ep2;
        {
                return (strcmp(ep->name, ep2->name));
        }

     will sort a set of names with associated flags in ASCII
     order.





January 1992                                                    1

qsort(3C)                                               qsort(3C)



NOTES
     The pointer to 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.  The order in the output of
     the two items that compare as equal is unpredictable.

SEE ALSO
     bsearch(3C), lsearch(3C), string(3C)

     sort(1) in A/UX Command Reference










































2                                                    January 1992