qsort (3f)

performs a quick sort of array elements

Syntax

  dimension array(1)
  integer*4 len, isize, compar      ! compar can be integer*2
  external qsort, compar
  call qsort ( array, len, isize, compar )

Description

  One dimensional array contains the elements to be sorted, while len is the
  number of elements in the array.  The isize argument is the size of an
  element, normally as follows:

      4                  Integer and real
      8                  Double precision and complex
     16                  Double complex
     (length of
     character object)   Character

  The compar argument is the name of a user-supplied integer or integer*2
  function that determines the sorting order.  You must declare compar as
  external (using an EXTERNAL statement) so it is recognized as a function.
  This function is called with two arguments that are elements of array. The
  function must return one of the following values:

     negative     If arg 1 is considered to precede arg 2
     zero         If arg 1 is equivalent to arg 2
     positive     If arg 1 is considered to follow arg 2

  On return, the elements of array are sorted.

See Also

  qsort(3)