Arrays of Pointers

Despite the F90 syntax restrictions, it is possible to create de facto arrays of pointers. For example, the sequence

type iptr  
 integer, pointer :: comp  
end type iptr  
type(iptr), dimension(100) :: I

declares a 100 dimensional vector whose components are pointers to integers. It is not possible to select sections of the I array

I(10)%comp    ! valid  
I(10:20)%comp ! invalid  

We can define an array of pointers to integer arrays

type IAptr  
 integer, dimension(:), pointer :: comp  
end type Iptr  
type(IAptr), dimension(100) :: IA

Each pointer component can then be made to point to an unnamed space in the heap,

allocate(IA(1)%comp(20), STAT=ierr) 

or can be made to point to an existing array

integer, target :: JA(10)  
ia(2)%comp => JA 

Note that ALLOCATABLE arrays cannot be components of derived types.