[svlug] ACCU meeting on Wednesday

Walter Vannini walterv at gbbservices.com
Mon Nov 13 10:57:04 PST 2006

When:      Wednesday, November 15, 2006
Topic:     Towards a Memory Model for C++
Speaker:   Hans Boehm
Time:      7:00pm
Where:     eBay Town Hall (next to PayPal/eBay)
                 2161 North First St
                 San Jose, CA 95131
Map:       <http://tinyurl.com/cdg5u/>
Cost:      Free
More Info: <http://www.accu-usa.org>

Many C and C++ programs use threads interfaces such as the pthreads API,
either for program structuring, or to take advantage of multiprocessors.
Although the pthreads specification gives fairly precise rules for
accessing shared variables in this environment, it turns out that these
are poorly understood by most programmers. Even when they are correctly
understood, they are not quite sufficient to ensure reliability of
multithreaded programs. These problems are known to generate occasional
very puzzling failures in practice. They also make it even harder to
teach programmers how to write multithreaded programs, a subject that is
certainly already difficult enough.

I will review what the rules are and explain when and why they are
insufficient. I will give an overview of the ongoing effort (with Doug
Lea, Bill Pugh, Peter Dimov, Clark Nelson, Alexander Terekhov, Andrei
Alexandrescu, others, and, at least so far, the strong support of the
C++ standards committee) to extend the C++ language specification to
address these issues. I will briefly explain why the issues seem to be
inherently different from languages such as Java and C#.

Although much of this is still a subject of active discussion, I will
present highlights of the current proposal. Even the uncontroversial
aspects of this proposal will unavoidably have significant impact on
code generation and optimization in C++ compilers.

Hans Boehm is the primary author of a widely used multithreaded garbage
collector library. He was HPs representative to the recently completed
effort to repair the Java "memory model", and is driving an ongoing
effort to extend the C++ standard with clean semantics for threads, and
particularly shared variable accesses.

He holds a Ph.D. from Cornell University. He is a past Chair of ACM
SIGPLAN, and of the POPL, ISMM and VEE research symposia. He won the
2003 PLDI most influential paper award, and the 2006 SIGPLAN
Distinguished Service Award. He works for HP Laboratories.

You can read about some of the recent C++ thread standardization
activity at Bill Venner's Artima site:

Upcoming ACCU talks

December 13, 2006
Allan Naim
"Production .NET Debugging"

January 10, 2007
Jeff Johnson
"Web Bloopers: Avoiding Common Design Mistakes"

February 7, 2007
Alex Martelli
"Technical Management of Software Developers"

March 21, 2007
Kevlin Henney
"Four (More) Patterns You Should Know"

The ACCU meets monthly. To suggest topics and speakers please
email Walter Vannini via walterv at gbbservices.com

Walter Vannini
President, Silicon Valley ACCU

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