(j3.2006) (SC22WG5.3703) Atomic stuff

[Aleksandar Donev]

Hi Van,

> 1.  Provide an attribute for a variable that says accesses to it are
> atomic.
While this may be preferable to the use of intrinsics, it is also much 
more complex to get right, especially in terms of matching of the 
attribute across association (can you point a nonatomic pointer to an 
atomic, how about arrays, etc.).

The other two ideas, while possibly technically useful, have nothing to 
do with ATOMIC. Until Fortran proper has accessors/updaters their use 
for atomic operations is out of the question.

I prefer alternative mechanisms to specify atomic operations (notably an 
ATOMIC block), but, that was not the goal. The goal was to provide some 
simple mechanism for spin loops and the like without the problems of 
VOLATILE. It is a compromise, and nobody's first preference. Nothing 
wrong with that, IMO, especially since it is just two intrinsics and not 
something that fundamentally messes up the language for eternity.

Best,
Aleks

-- 
Aleksandar Donev, Ph.D.
Lawrence Postdoctoral Fellow @ LLNL
High Performance Computational Materials Science and Chemistry
E-mail: donev1 at llnl.gov
Phone: (925) 424-6816  Fax: (925) 423-0785
Address: P.O.Box 808, L-367, Livermore, CA 94551-9900
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