Re: [Mingw-users] new thread library aimed at c++11 and later development.

[K. F. <kfr...@gm...>]

Hi Eli!

On Sat, Jul 9, 2016 at 3:36 AM, Eli Zaretskii <el...@gn...> wrote:
>> From: ralph engels <ral...@gm...>
>> Date: Wed, 6 Jul 2016 01:53:21 +0200
>>
>> I will try, atm we just need to know if the gcc i have built works on
>> windows versions older than vista,
>> ...
>> No need to run the entire gcc suite as atleast one c++ test is known to
>> fail, but that test might be suspect.
>
> I can run the single test program mentioned there, but I'd appreciate
> more details, as I don't normally use C++ in my personal work.
>
> A list of test programs to compile, the non-default command-line
> switches to compile them, how to run them, and what results to expect
> will be greatly appreciated.

Disclaimer:  This info is five or six year old, I did not do this on xp
(rather 64-bit windows 7), I think I did this with mingw-w64 (although
I might have also run it with mingw), and I used a hand-patched
version of gcc prior to either mingw or mingw-w64 offering support
for std::thread.

I downloaded the source code for (part of?) the gcc std::thread test
suite from:

   http://gcc.gnu.org/viewcvs/trunk/libstdc%2B%2B-v3/testsuite/30_threads/thread/cons/

I also had to download testsuite_hooks.h (and maybe also all.h) from

   http://stuff.mit.edu/afs/athena/software/gccgo_v4.50/gccgo/libstdc++-v3/testsuite/util/testsuite_hooks.h

(and http://stuff.mit.edu/afs/athena/software/gccgo_v4.50/gccgo/libstdc++-v3/testsuite/util/thread/all.h).

I do not believe that I had to download or use testsuite_hooks.cc.

The first test program I tried was 1.cc.  I compiled it as follows:

   g++ --D_GLIBCXX_ASSERT D_GLIBCXX__EXP_THREADS
-D_GLIBCXX_HAS_GTHREADS -enable-stdcall-fixup -enable-auto-import
-std=c++0x -I.. -o 1 1.cc

I think that some of these command-line argument should not be
necessary for you.  From memory:

   -D_GLIBCXX_ASSERT   causes the test code's VERIFY macro to become a
      run-time assertion
   -D_GLIBCXX__EXP_THREADS    tells gcc to use my gthreads implementation that
      supports my experimental std::thread implementation
   -D_GLIBCXX_HAS_GTHREADS   needed to turn on gthreads in gcc
   -enable-stdcall-fixup   I think this was a work-around for some
windows gcc issue
      that presumably no longer exists
   -enable-auto-import  again, a work-around that is probably no
longer necessary
   -std=c++0x   turn on c++11 to enable std::thread
   -I..   tell gcc to search my current working directory to find
testsuite_hooks.h

   -o 1 1.cc   compile 1.cc and output executable to 1.exe

In short, the only command-line arguments I think you would need would
be -D_GLIBCXX_ASSERT, -std=c++11 (or maybe std=c++14), unless
your version of gcc defaults (finally) to using c++11 / c++14, and -I ..,
or equivalent, to make testsuite_hooks.h available.  All the other stuff I
think are no-longer-relevant work-arounds and stuff special to my patched
gcc installation.

>From memory, I did not have to modify any of the test suite code.  I just
had to manually download, compile, and run it, independently of the testing
framework that I didn't bother to port / set up.

I think some of the tests are supposed to "fail" (assert) as the condition
for success.

I also ran the test-suite program, typesizes.cc that tested whether a pointer
to a thread handle had the same size as the thread handle itself.  This is a
weird test that did not pass for me, and I did not expect it to pass.  This may
be related to the issue that, although not required by posix,
unix-world pthreads
uses a scalar type (a pointer) as its (nominally opaque) thread handle, and much
pthreads-using code in the wild (including gcc's std::thread) depends on this.
pthreads-win32, however, uses a non-scalar struct for the handle.  I got around
this by patching gcc's std::thread to work with a non-scalar thread handle.
(mingw-w64 elected to write winpthreads that follows the de facto unix-world
standard of using a scalar handle, and use that to support std::thread.)

I hope this of some use to you, but beware that this is all 5+ years old.
These comments may no longer be relevant to the current test-suite code
(and the source-code links I gave above may or may not still be in service).

> TIA


Happy Multi-Threaded Hacking!


K. Frank