A deferred-shape array is an array pointer or an allocatable array.

  The array specification contains a colon (:) for each dimension of
  the array.  No bounds are specified.  The bounds (and shape) of
  allocatable arrays and array pointers are determined when space is
  allocated for the array during program execution.

  An array pointer is an array declared with the POINTER attribute.
  Its bounds and shape are determined when it is associated with a
  target by pointer assignment, or when the pointer is allocated by
  execution of an ALLOCATE statement.

  In pointer assignment, the lower bound of each dimension of the
  array pointer is the result of the LBOUND intrinsic function
  applied to the corresponding dimension of the target.  The upper
  bound of each dimension is the result of the UBOUND intrinsic
  function applied to the corresponding dimension of the target.

  A pointer dummy argument can be associated only with a pointer
  actual argument.  An actual argument that is a pointer can be
  associated with a nonpointer dummy argument.

  A function result can be declared to have the pointer attribute.

  An allocatable array is declared with the ALLOCATABLE attribute.
  Its bounds and shape are determined when the array is allocated by
  execution of an ALLOCATE statement.

  The following are examples of deferred-shape specifications:

    REAL, ALLOCATABLE :: A(:,:)       ! Allocatable array
    REAL, POINTER :: C(:), D (:,:,:)  ! Array pointers