ASSOCIATED (pointer [,target])

  Class:  Inquiry function - Generic

  Returns the association status of its pointer argument or indicates
  whether the pointer is associated with the target.  The pointer
  must not have an undefined association status.

  The "target" can be a pointer or target.

  If only POINTER appears, the result is true if it is currently
  associated with a target; otherwise, the result is false.

  If TARGET also appears and is a target, the result is true if
  POINTER is currently associated with TARGET; otherwise, the result
  is false.

  If TARGET is a pointer, the result is true if both POINTER and
  TARGET are currently associated with the same target; otherwise,
  the result is false.  (If either POINTER or TARGET is
  disassociated, the result is false.)

  The setting of integer size compiler options can affect this
  function.

  Examples:

  Consider the following:

     REAL, TARGET, DIMENSION (0:50) :: TAR
     REAL, POINTER, DIMENSION (:) :: PTR
     PTR => TAR
     PRINT *, ASSOCIATED (PTR, TAR)    ! Returns the value true

  The subscript range for PTR is 0:50.  Consider the following
  pointer assignment statements:

     (1) PTR => TAR (:)
     (2) PTR => TAR (0:50)
     (3) PTR => TAR (0:49)

  For statements 1 and 2, ASSOCIATED (PTR, TAR) is true because TAR
  has not changed (the subscript range for PTR in both cases is 1:51,
  following the rules for deferred-shape arrays).  For statement 3,
  ASSOCIATED (PTR, TAR) is false because the upper bound of PTR has
  changed.

  Consider the following:

     REAL, POINTER, DIMENSION (:) :: PTR2, PTR3
     ALLOCATE (PTR2 (0:15))
     PTR3 => PTR2
     PRINT *, ASSOCIATED (PTR2, PTR3)   ! Returns the value true
     ...
     NULLIFY (PTR2)
     NULLIFY (PTR3)
     PRINT *, ASSOCIATED (PTR2, PTR3)   ! Returns the value false