On 2022-10-21 09:58, Jonathan Wakely via Libstdc++ wrote:
How does this compare with Eric B's proposal at
https://gcc.gnu.org/legacy-ml/gcc-patches/2019-06/msg01840.html ?
It would be good if we can accept one of them for GCC 13, but I don't
know Windows well enough to determine which is better.
I had the same question...
I would like to understand what is the difference?
Moreover I would like to understand what is the difference with the
already added support for the winpthreads library?
@LIU Hao, could you explain please?
best!
On Sat, 1 Oct 2022 at 19:35, LIU Hao via Libstdc++
<libstd...@gcc.gnu.org> wrote:
Greetings.
After some years I think it's time to put on this topic again.
This patch series is an attempt to add a new thread model basing on
the mcfgthread library
(https://github.com/lhmouse/mcfgthread), which provides efficient
implementations of mutexes,
condition variables, once flags, etc. for native Windows.
The first patch is necessary because somewhere in libgfortran,
`pthread_t` is referenced. If the
thread model is not `posix`, it fails to compile.
The second patch implements `std::thread::hardware_concurrency()` for
non-posix thread models. This
would also work for the win32 thread model if `std::thread` would be
supported in the future.
The third patch adds the `mcf` thread model for GCC and its libraries.
A new builtin macro
`__USING_MCFGTHREAD__` is added to indicate whether this new thread
model is in effect. This grants
`std::mutex` and `std::once_flag` trivial destructors;
`std::condition_variable` is a bit
unfortunate because its destructor is non-trivial, but in reality no
cleanup is performed.
I have been bootstrapping GCC with the MCF thread model for more than
five years. At the moment, C,
C++ and Fortran are supported. Ada is untested because I don't know
how to bootstrap it. Objective-C
is not supported, because threading APIs for libobjc have not been
implemented.
Please review. If there are any changes that I have to make, let me
know.
--
Best regards,
LIU Hao
