Doc:    ISO/IEC JTC 1/SC 22/WG 21  N0961R1
              Date:   11-July-95
              Subj:   Response to liason statement SC 24/N 1577
                        from SC 24/WG 6.
              Ref:    ISO/IEC JTC 1/SC 24/N 1577
              Contact:
                      Sam Harbison, WG21 Convener
                      Texas Instruments
                      300 Oxford Drive
                      Monroeville, PA 15146
                      +1(412) 856-3600 x147
                      harbison@tartan.com
 
 
WG21 acknowledges the liason statement from SC 24/WG 6 (SC 24/N 1577==
SC 22/WG 21/N 0960) and thanks the authors for their contribution.  The
statement was distributed and discussed at WG21's Stockholm meeting on
7-Jul-96. Mr. Karl Soop also attended the meeting on behalf of SC 24/WG 6,
and explained the background of the liason statement.
 
The provision of support for concurrency in C++ has been discussed
within WG21.  Various implementations of C++ have provided concurrency
in several forms.  A recently published book from MIT Press(*) lists 18
different implementations of concurrency in C++, some involving language
extensions and others using library facilities.  The implementations
have different capabilities and purposes.  Although it would clearly be
a benefit to the programming community, an attempt to agree on one
concurrency facility for all C++ programmers would be difficult at this
time.
 
The C++ standard is now at the CD stage, and no national body has
requested the addition of concurrency support in their CD ballot
comments. Therefore, WG21 feels it would be inappropriate to take on the
task of adding such support as part of its current standard, even as an
informative annex.  Of course, such a facility could be proposed later
as an adendum or a technical report. If the facility were implemented as
an optional library, it could also be advanced by another working group,
e.g., SC 24/WG 6.
 
Mr. Dag Bruck (dag@dynasim.se), a representative of Sweden to WG21, has
volunteered to be the point of contact should WG6 wish to continue to
discuss the technical details of their proposal.
 
(*) Mr. Bruck will be able to supply the exact reference to this book.