On 6 March 2017 at 23:14, Edward Diener via Boost wrote:

Do any Boost libraries really target gnu features, if they exist, that are not in the corresponding c++ level ? If not there is no reason to test the gnu levels and the c++ levels seem just fine. I know that I do not specifically test gnu levels but c++ levels instead when I run local tests.

Does Boost.Multiprecision depend on the __int128 and __float128 extensions? std::is_integral<__int128>::value is true for gnu++14 but false for c++14

The problem with clang targeting the MSVC ABI, as far as Boost is concerned, is that it erroneously implements the non-standard VC++ preprocessor. This makes it all but useless for using with Boost. That it should have even been designed to do this for all macros, rather than just for the macros it needed when processing VC++ and Windows headers, is its major downfall. When you have to emulate something that is already non-standard, and for which no internal knowledge is available, you are already on the wrong path.

You can tell C2 clang to not use MSVC compatibility and VS2015 Update 2 and later's headers will now compile cleanly. I would assume VS2017 is the same. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

On 07/03/2017 16:48, Edward Diener via Boost wrote:

On 3/7/2017 9:47 AM, Niall Douglas via Boost wrote:

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The problem with clang targeting the MSVC ABI, as far as Boost is concerned, is that it erroneously implements the non-standard VC++ preprocessor. This makes it all but useless for using with Boost. That it should have even been designed to do this for all macros, rather than just for the macros it needed when processing VC++ and Windows headers, is its major downfall. When you have to emulate something that is already non-standard, and for which no internal knowledge is available, you are already on the wrong path.

You can tell C2 clang to not use MSVC compatibility and VS2015 Update 2 and later's headers will now compile cleanly. I would assume VS2017 is the same.

Where is C2/clang available for download ? It seems the only thing that is not mentioned in the C2/clang blogs. Nice going Microsoft !

In the VS2017 installer, you just choose C2 clang just as you would any other component. I can't remember if Visual Studio's default project settings turn on MSVC compatibility, but if they do, turn it off. Bar newly introduced bugs in the headers (ping Stephan on those), C2 clang is compiling the Windows SDK headers fairly well without MSVC emulation. There are some warnings at -Wall though. Note cmake et al don't understand the new path locations in VS2017 yet and it's a pain. HOWEVER you can now load cmake projects straight into VS2017 whereupon they find the new toolset because VS2017 ships a custom cmake internally. It's incredibly slow though, almost unusably slow. And VS2017 in cmake mode gets very badly confused frequently i.e. it's buggy. (Before someone from Microsoft asks for me to report the bug, let me suggest to you to go install WSL and try running cmake-within-WSL on the same project as VS2017 has loaded via cmake. It's a disaster, and a real impediment to the whole point of cmake project loading, you need to add some logic to account for concurrent cmake-outside-of-VS2017 especially when that is Linux cmake not Windows cmake) Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

On 2017-03-07 20:01, Edward Diener via Boost wrote:

On 3/7/2017 12:12 PM, Niall Douglas via Boost wrote:

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On 07/03/2017 16:48, Edward Diener via Boost wrote:

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On 3/7/2017 9:47 AM, Niall Douglas via Boost wrote:

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The problem with clang targeting the MSVC ABI, as far as Boost is concerned, is that it erroneously implements the non-standard VC++ preprocessor. This makes it all but useless for using with Boost. That it should have even been designed to do this for all macros, rather than just for the macros it needed when processing VC++ and Windows headers, is its major downfall. When you have to emulate something that is already non-standard, and for which no internal knowledge is available, you are already on the wrong path.

You can tell C2 clang to not use MSVC compatibility and VS2015 Update 2 and later's headers will now compile cleanly. I would assume VS2017 is the same.

Where is C2/clang available for download ? It seems the only thing that is not mentioned in the C2/clang blogs. Nice going Microsoft !

In the VS2017 installer, you just choose C2 clang just as you would any other component.

Your mention of VS2015 Update 2 above led me to think it was some downloadable software available for that product. Now I realize that it is available for VS2017 currently being launched. So much hubbub for a product which is just now being officially made available has confused me. I have this bad habit of waiting until some software actually officially exists and can be used before I become interested in it. Excuse me <g> !

It is available in the VS2015 installer as well. And has been all the time. But if you want to try it out now, from today VS2017 would be the obvious choice. :-) Bo Persson

On 3/7/2017 2:24 PM, Bo Persson via Boost wrote:

On 2017-03-07 20:18, Bo Persson via Boost wrote:

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On 2017-03-07 20:01, Edward Diener via Boost wrote:

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On 3/7/2017 12:12 PM, Niall Douglas via Boost wrote:

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On 07/03/2017 16:48, Edward Diener via Boost wrote:

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On 3/7/2017 9:47 AM, Niall Douglas via Boost wrote:

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> The problem with clang targeting the MSVC ABI, as far as Boost is > concerned, is that it erroneously implements the non-standard VC++ > preprocessor. This makes it all but useless for using with Boost. > That > it should have even been designed to do this for all macros, rather > than > just for the macros it needed when processing VC++ and Windows > headers, > is its major downfall. When you have to emulate something that is > already non-standard, and for which no internal knowledge is > available, > you are already on the wrong path.

You can tell C2 clang to not use MSVC compatibility and VS2015 Update 2 and later's headers will now compile cleanly. I would assume VS2017 is the same.

Where is C2/clang available for download ? It seems the only thing that is not mentioned in the C2/clang blogs. Nice going Microsoft !

In the VS2017 installer, you just choose C2 clang just as you would any other component.

Your mention of VS2015 Update 2 above led me to think it was some downloadable software available for that product. Now I realize that it is available for VS2017 currently being launched. So much hubbub for a product which is just now being officially made available has confused me. I have this bad habit of waiting until some software actually officially exists and can be used before I become interested in it. Excuse me <g> !

It is available in the VS2015 installer as well. And has been all the time.

But if you want to try it out now, from today VS2017 would be the obvious choice. :-)

Oh, and the reference to Update 2 is when it started to compile the Windows headers without any special options.

I installed the "Clang with Microsoft codegen", aka C2/clang, for VS2015 in order to see what I might need to do to integrate it into Boost PP/VMD. I then went looking for documentation in the VS2015 IDE Help for how to use it either from the IDE or command line. Absolutely no documentation exists within Visual Studio 2015 about it, nor is there any official docs anywhere on the web which I could find. I doubt very much whether this is a viable option in VS2015 for compiling Boost libraries. I will take a look again with VS2017, which I have just downloaded, but considering that no documentation for this exists AFAICS I highly doubt whether this Microsoft offering, whatever it is, will work with Boost. Call me a skeptic, but if I a C++ product is released without documentation, whether from Microsoft or anyone else, I have great doubts that it will actually work with C++ standard code.

Bo Persson

On 3/8/2017 11:39 AM, degski via Boost wrote:

On 8 March 2017 at 09:34, Edward Diener via Boost wrote:

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I installed the "Clang with Microsoft codegen", aka C2/clang, for VS2015 in order to see what I might need to do to integrate it into Boost PP/VMD. I then went looking for documentation in the VS2015 IDE Help for how to use it either from the IDE or command line. Absolutely no documentation exists within Visual Studio 2015 about it, nor is there any official docs anywhere on the web which I could find. I doubt very much whether this is a viable option in VS2015 for compiling Boost libraries. I will take a look again with VS2017, which I have just downloaded, but considering that no documentation for this exists AFAICS I highly doubt whether this Microsoft offering, whatever it is, will work with Boost. Call me a skeptic, but if I a C++ product is released without documentation, whether from Microsoft or anyone else, I have great doubts that it will actually work with C++ standard code.

This SO question glosses http://stackoverflow.com/questions/42593423/whats-the-difference-between-cla... over the what and why of Clang/C2 (vs Clang/LLVM).

Thanks for the link, but it hardly qualifies as documentation for that product. If it is like clang for Windows targeting VC++ it has a broken emulation of the non-standard VC++ preprocessor which makes it more than useless to me.

degski

On 3/8/2017 1:13 PM, Peter Dimov via Boost wrote:

Edward Diener wrote:

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If it is like clang for Windows targeting VC++ it has a broken emulation of the non-standard VC++ preprocessor...

You can disable its MS compatibility mode, which ought to disable the broken preprocessor emulation. The article for 2017 is here:

https://blogs.msdn.microsoft.com/vcblog/2017/03/07/use-any-c-compiler-with-v...

and on the screenshot in the Clang section the option for Microsoft Compatibility Mode is shown in a default state of "No".

Thanks for the link.

On 3/9/2017 8:36 AM, degski via Boost wrote:

On 8 March 2017 at 11:47, Edward Diener via Boost wrote:

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Thanks for the link, but it hardly qualifies as documentation for that product. If it is like clang for Windows targeting VC++ it has a broken emulation of the non-standard VC++ preprocessor which makes it more than useless to me.

... about as useless as cl.exe (C1/C2) itself, I guess...

You have missed the point in regard to Boost. The point is: 1) VC++, although having a non-standard C++ preprocessor, will work with Boost PP/VMD because of the workarounds programmed in those libraries to deal with that compiler. 2) Clang targeting VC++ has a broken emulation of the non-standard VC++ preprocessor, which means it will not work with Boost PP/VMD. 3) Many Boost libraries use Boost PP for their preprocessing tasks. 4) Therefore many Boost libraries will not work with clang targeting VC++. 5) I have reported to clang bugs regarding their broken emulation of the non-standard VC++ preprocessor, and they have completely ignored those bug reports. 6) Therefore if clang/C2, or whatever is the latest name Microsoft has given to their largely undocumented product, also contains the broken emulation of the non-standard VC++ preprocessor, it will not work with Boost. 7) If there is a mode by which clang/C2 does not use the broken emulation of the non-standard VC++ preprocessor, but instead implements clang's usual C++ standard preprocessor, as Peter Dimov has suggested, there is no Boost Build support for clang/C2 AFAICS to test this. 8) I am not willing to try to change Boost PP/VMD to work with clang's broken emulation of the non-standard VC++ preprocessor. If anyone else would like to do it, please go ahead. Getting Boost PP/VMD to work with the non-standard VC++ preprocessor was enough work, as I am pretty sure that Paul Mensonides who did that for Boost PP will attest also. This is what I mean when I say that clang/C2 is currently useless to me as someone who programs using Boost libraries. Personally it may be great for VC++ developers despite its almost total lack of documentation, but it is not ready for programming using Boost.

The only usefullness of the Clang/C2 combo is the better debugging support it provides (as compared to Clang/LLVM)... Clang/C2 cannot beat Clang/LLVM, at best it's on par (but often not) and it's released version is lagging the clang/LLVM release schedule.... As/when used from the IDE, Clang/LLVM integrates and works well... makes programming in C++ on Windows much more pleasant (more comprehensible error messages, although the M$ STL doesn't always help in this regard) and often generates better code...

As to docs: the exe's do have (clang) help screens, accessible from the command-line. General Clang/LLVM docs on the web-site...

As to vapourware: I guess it is, since AFAIK it (Clang/C2) is still an 'experimental' project, and as such not supported (as in 'don't use in production code').

degski

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Oh, and the reference to Update 2 is when it started to compile the Windows headers without any special options.

I installed the "Clang with Microsoft codegen", aka C2/clang, for VS2015 in order to see what I might need to do to integrate it into Boost PP/VMD. I then went looking for documentation in the VS2015 IDE Help for how to use it either from the IDE or command line. Absolutely no documentation exists within Visual Studio 2015 about it, nor is there any official docs anywhere on the web which I could find. I doubt very much whether this is a viable option in VS2015 for compiling Boost libraries. I will take a look again with VS2017, which I have just downloaded, but considering that no documentation for this exists AFAICS I highly doubt whether this Microsoft offering, whatever it is, will work with Boost. Call me a skeptic, but if I a C++ product is released without documentation, whether from Microsoft or anyone else, I have great doubts that it will actually work with C++ standard code.

I vaguely remember Boost Build added support for C2 clang a while back. That would be VS2015 located C2 clang, VS2017 uses some very weird path for it. cmake has also built in support for C2 clang, it's something like -T v140_clang_c2. In terms of documentation for it, basically it works like LLVM clang except for additional ICEs, it doesn't support a lot of the SIMD intrinsics, and you can debug its output fully. A really fun thing you can do with C2 clang is turn on the sanitisers and they nearly actually work. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

On 3/7/2017 2:18 PM, Bo Persson via Boost wrote:

On 2017-03-07 20:01, Edward Diener via Boost wrote:

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On 3/7/2017 12:12 PM, Niall Douglas via Boost wrote:

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On 07/03/2017 16:48, Edward Diener via Boost wrote:

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On 3/7/2017 9:47 AM, Niall Douglas via Boost wrote:

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The problem with clang targeting the MSVC ABI, as far as Boost is concerned, is that it erroneously implements the non-standard VC++ preprocessor. This makes it all but useless for using with Boost. That it should have even been designed to do this for all macros, rather than just for the macros it needed when processing VC++ and Windows headers, is its major downfall. When you have to emulate something that is already non-standard, and for which no internal knowledge is available, you are already on the wrong path.

You can tell C2 clang to not use MSVC compatibility and VS2015 Update 2 and later's headers will now compile cleanly. I would assume VS2017 is the same.

Where is C2/clang available for download ? It seems the only thing that is not mentioned in the C2/clang blogs. Nice going Microsoft !

In the VS2017 installer, you just choose C2 clang just as you would any other component.

Your mention of VS2015 Update 2 above led me to think it was some downloadable software available for that product. Now I realize that it is available for VS2017 currently being launched. So much hubbub for a product which is just now being officially made available has confused me. I have this bad habit of waiting until some software actually officially exists and can be used before I become interested in it. Excuse me <g> !

It is available in the VS2015 installer as well. And has been all the time.

You are right. I missed it when installing. It is called "Clang with Microsoft codegen" in the VS2015 install.

But if you want to try it out now, from today VS2017 would be the obvious choice. :-)

Understood. Thanks !

Bo Persson

On Wed, Mar 8, 2017 at 1:51 AM, Ben Pope via Boost wrote:

On 06/03/17 22:50, Tom Kent via Boost wrote: No, thank you. My 34" 21:9 screen can no longer fit all of your configurations on it (at native res); you may single-handedly be a justification for an even larger screen and/or for somebody to fix the report generation speed.

4K and 5K were invented for a reason, you know? ;) -- Olaf