[J3] [EXTERNAL] Re: Changing address of an allocatable on assignment when shapes match

Malcolm Cohen malcolm at nag-j.co.jp
Sat Aug 24 01:29:01 EDT 2019

The breakage would be if you moved the target, a pointer to that target would stop working, i.e. the semantics would be broken.

Unless, of course, one updates all the associated pointers when you move a target (like compacting garbage collectors do).


From: Vipul Parekh via J3 
Sent: Saturday, August 24, 2019 12:14 PM
To: General J3 interest list 
Cc: Vipul Parekh 
Subject: Re: [J3] [EXTERNAL] Re: Changing address of an allocatable on assignment when shapes match

I couldn't understand the statement, "In general, it would not be
conforming to do the reallocation if the allocatable array has the
TARGET attribute, as this would break the Fortran pointer association
semantics" - can someone please point me to the relevant section(s)
(and paragraph(s)) in the standard that might explain it for me?

Vipul Parekh

On Fri, Aug 23, 2019 at 9:16 PM Malcolm Cohen via J3
<j3 at mailman.j3-fortran.org> wrote:
> We do say so! We state precisely when “reallocation” happens. It’s not called “reallocation” either; it is called “deallocating” followed by “allocating”.
> And “reallocation” is already in the reasons, seeing as how it is stated as “deallocation”, which is already in the reasons. ..


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