qsort(3C)                      DG/UX R4.11MU05                     qsort(3C)


NAME
       qsort - quicker sort

SYNOPSIS
       #include <stdlib.h>

       void qsort (void* base, sizet nel, sizet width, int (*compar)
           (const void *, const void *));

DESCRIPTION
       qsort is an implementation of the quicker-sort algorithm.  It sorts a
       table of data in place.  The contents of the table are sorted in
       ascending order according to the user-supplied comparison function.

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

       The contents of the table are sorted in ascending order according to
       the user supplied comparison function.


   Considerations for Threads Programming
                     +---------+-----------------------------+
                     |         |                      async- |
                     |function | reentrant   cancel   cancel |
                     |         |             point     safe  |
                     +---------+-----------------------------+
                     |qsort    |     Y         N        N    |
                     +---------+-----------------------------+

SEE ALSO
       reentrant(3), bsearch(3C), lsearch(3C), string(3C).
       sort(1).

NOTES
       The user-supplied comparison function must be symmetrical and
       transitive.

       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 relative order in the output of two items that compare as equal
       is unpredictable.


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