Subject: Re: 2 more items

From: [email-masked]
Date: Thu, 3 Dec 1992 14:18:40 -0600

At 16:46 12/2/92 -0800, Mary E Zosel wrote:
>To: F90 subgroup
>
>Two more items for us to discuss came to my attention since the first
>note a while ago.  I would like to start you thinking about them.
>
>(1) Metcalf asked if we had considered BIT_SIZE  for the subset. This
>intrinsic gives back the number of bits in integers for various values
>of KIND ... without KIND in the subset, I guess it would give back the
>value of the default integer size.  Comments?  

Sounds reasonable to me.  Of course, not defining the result also sounds
reasonable (i.e. in full F90, BIT_SIZE(k) doesn't seem to be defined if
KIND=k is not in the implementation).

>(2) My records show that we voted not to have the EXTRINSIC directive
>in the subset.  Is this a mistake?  We KNOW there is going to be
>a need to escape HPF for system things, for messages, for ... do we
>just close our eyes and let vendors do what comes in the subset - or
>do we at least provide the directive that declares an external being
>called is not a regular part of the HPFF data-parallel, SPMD world.
>As the keeper of the subset chapter, I think we should make a
>recommendation about this to the full committee. 
>
>   -mary-

My notes agree with yours re: voting EXTRINSICS out.  (It appears to have
been an official vote, not a straw poll.)

My memory is hazy, but I think the objection was to the (fairly strict)
semantics imposed, particularly requiring all processors to be involved in
the EXTRINSIC call.  My notes include an anonymus statement that the
original justification (calling system/other language routines) is not
precisely true, and Richard Swift's argument that EXTRINSIC is not (was not
at the meeting) well-defined.  Rich Shapiro (at least) argued that it was
needed, pretty much on the same grounds you gave.

I tend to agree with Swift on this one - we don't want to require a
semantics that may not be solid in the subset.  Leaving EXTRINSIC out may
mean that a majority of vendors will implement the subset + one feature;
that's OK.  (Yes, this optimistically assumes they will implement EXTRINSIC
functions before DOIT_MYWAY functions.)

                                               Chuck