Re: Threading in new C++ standard
On Apr 25, 10:33 am, Szabolcs Ferenczi <szabolcs.feren...@gmail.com>
wrote:
On Apr 24, 7:05 pm, Pete Becker <p...@versatilecoding.com> wrote:
On 2008-04-24 12:37:40 -0400, Szabolcs Ferenczi
<szabolcs.feren...@gmail.com> said:
...
I remember having seen a number of arguments that day going that the
library solution is not adequate (with reference to the paper of
Boehm) and that C++0x goes for a language-based approach instead.
That's not correct, as several people have told you.
Several people keep saying that there are language elements
for multi-threading in C++0x but nobody could enumerate any
single languge element so far.
The Boehm paper explained them in detail. Several people have
suggested that you read it. In the current standard, the basic
execution and memory models start from the point of view that
code is executed sequentially.
Several people did not reply to my request to point out what
are the language elements for concurrency in the proposed
C++0x standard. When I make a list for them, asking (1) what
are the language elements for starting a thread of
compulation, (2) by which language elements mutual exclusion
is specified, (3) what are the language elements for making
the threads synchronised---the answer is silence or ignorance
from several people. (Ok, one of them has admitted that these
are at the library level rather than at the language level.)
No. Several people have pointed out several times where the
language addresses concurrency issues.
[...]
You're not right that it's a "pure library approach". The
library can't be implemented correctly without compiler
support,
Many libraries are implemented so far correctly (without any
compiler support), as far as I know.
The ones I know all depend on compiler support. It's not
defined by the language standard, but it is available as an
extension in many compilers. Not always in compatible manners,
of course.
The missing compiler support for algorithms written on top of
those libraries is another question. Still, correct concurrent
programs must be obeyed by the compiler otherwise there is a
problem in the compiler.
It's still standard conforming.
Without this you cannot write a reliable, portable multi-threaded
application.
Hmmm... How about portable multi-threaded applications written
so far?
Do you know of any? Without some sort of platform dependencies?
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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