(j3.2006) a question on c_f_pointer call

[Aleksandar Donev]

On 08/25/10 15:34, Jim Xia wrote:
> From implementation point of view, how can one tell if FPTR is 
> eligible for deallocation?  The CPTR is simply a C pointer, no 
> necessary information as to whether they can be deallocated. 
You have to look to your allocator, it seems to me. How do you do it now 
for this code:

-----------------
real, dimension(:), pointer :: p1, p2

allocate(p2(2:11))

call point_to(p1,p2,10)

deallocate(p1,stat=...)

where

subroutine point_to(p,t,n)
     integer :: n
     real, pointer :: p(:)
     real, target :: t(:)
     p=>t(1:n)
end subroutine
-----------------

It seems to me this is legal and does not use C pointers. How do you 
establish whether p1 can be deallocated? I am trying to understand why 
exactly c_f_pointer is special from using some library that does pointer 
assignments like above.

Best,
Aleks

-- 
Aleksandar Donev, Assistant Professor of Mathematics
Courant Institute of Mathematical Sciences
Office: 909 Warren Weaver Hall, New York University
E-mail: donev at courant.nyu.edu
Phone: (212) 992-7315; Fax: (212) 995-4121
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Web: http://cims.nyu.edu/~donev

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