(j3.2006) enhanced ASYNCHRONOUS attribute

[Robert Corbett]

On 07/13/11 03:36, Bill Long wrote:
>
>
> On 7/13/11 3:38 AM, Robert Corbett wrote:
>> Does Clause 2.4 of DPTR 29113 change the language
>> specified by the Fortran 2008 standard in any way?
>
> In practice, yes.  A Fortran implementation that implements all 
> asynchronous I/O as synchronous I/O (allowed by the standard) can 
> effectively ignore the ASYNCHRONOUS attribute.  The new wording 
> disallows that option.
As I said before, the restrictions given in Clause 2.4 are
restrictions on programs, not processors.  I understand
that there should be restrictions on what a standard-
conforming processor may do, but I do not see those
restrictions in Clause 2.4.

Suppose a program does an input communication asynchronously
using procedures written in a language other than Fortran.
Suppose the initiation procedure names a variable with the
ASYNCHRONOUS attribute but not the TARGET or VOLATILE
attributes as the input variable.  Suppose the completion
procedure does not name the input variable.  I see nothing in
the DPTR that prohibits a processor from loading the value of
the variable before the completion procedure is called for
use in the execution of a statement after the completion
procedure is called.

Bob Corbett