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[container] static_string ?
by Vinnie Falco 09 Nov '19

09 Nov '19

Beast has static_string which someone has asked to be move, is there any interest in moving this to Boost.Container? See: <https://github.com/boostorg/beast/issues/1691> <https://github.com/boostorg/beast/blob/b7230f12f16fe7a9f7a1ece5be1f607c8552…> -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

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[Metrics] - library idea reviews
by cpijcke.wall＠laposte.net 08 Nov '19

08 Nov '19

Hi, Two years ago, I have created a library who handle metrics type (distance, speed, flow rate, ...). I have simply applied the principle of chrono library (std:: one from clang in my case) and have applied it to other types. I have decided some weeks ago to make it public on github. This project also manage inter-type conversion(speed to distance, or volume to flow rate for example). Before going much further in this project, I would like to get your though about it. Maybe some of you already have had a similar idea, maybe even in a more advanced state, or with another principle of conversion between types? Here is the project link: https://github.com/xtofpic/metrics if you are interested. In this case, don't blame me for the state of the code actually, I know it still need a huge works to do on testing and code reducing by better c++ templates. But if you can just let me know what you think of the idea? And if there is an opportunity to eventually integrate this project into boost afterwards? Best regards, Christophe Pijcke.

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How to make boost write_xml not escape angle brackets?
by Ananya Maiti 07 Nov '19

07 Nov '19

Hi all, I am trying to write some data in a xml file using boost write_xml() function. My data has some angle brackets in it e.g. <![CDATA[name]]> . But when I use boost::property_tree::write_xml() to write the data node to xml file it escapes the angle brackets to < and > tags. I even tried using unicode \x3C , \x3E but still it escapes them. Is there any way to tell boost to not escape the characters in a non html safe way ? Regards, Ananyo Maiti

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[1.72][Test][Math][Fiber] Recent breaking change in Boost.Test breaks fiber/math tests
by John Maddock 07 Nov '19

07 Nov '19

This change: https://github.com/boostorg/test/commit/1c4533f7654d4c049cc6a34a43a5c10cde5… To Boost test (which I'm sure has been long signaled, I just wasn't aware of it), breaks one Math lib test (develop and master), and quite a number of Fibre tests (also develop and master), the Math failure should be fixed in develop (https://github.com/boostorg/math/commit/1d04bf714e809d386088ce135e3f9ea04ca…) and will get merged to master once CI is green. Not sure if anything is in the works for Fiber. Just a wee heads-up. Best, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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Best Boost to use for boost::python with Python 3.7/3.8?
by Kacvinsky, Tom 06 Nov '19

06 Nov '19

Subject is the question. Any recommendations? Looking at the boost documentation for boost::python, it doesn't look like the copyright has changed since 2015, but compiling boost 1.6.9.0, for instance, points out there have been code changes.

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[Test] log_level (was RE: [1.72][Test][Math][Fiber] Recent breaking change in Boost.Test breaks fiber/math tests)
by Peter Bartlett 05 Nov '19

05 Nov '19

>I think it is very counter-intuitive that messages only emerge to the normal output if there is an error or --log_level="message" > >And that > > #define BOOST_TEST_LOG_LEVEL "message" > >does not appear to have the same effect as --log_level="message" > >which is also surprising, and in my book a buglet? > >I suggest that this behaviour should be changed so that BOOST_TEST_MESSAGE >*always* produces output. > >BOOST_AUTO_TEST_CASE(test_message) >{ > BOOST_TEST_MESSAGE("\nTest BOOST_TEST_MESSAGE.\n"); } // BOOST_AUTO_TEST_CASE(test_message) > >Otherwise I am sure I will not be the only person confused. > >At the very least the documentation should highlight that ones expectation may not match what actually happens. Hi, I think it would be a bad idea to change the default value of --log_level (in your suggestion, from "error" to "message"). The default has been "error" for a long time (I don't like to count how long, because it makes me feel old!). And I'm sure that a lot of parsing tools have been built around the world assuming Boost.Test output is of a certain form. I know I've had to 'teach' various CI systems Boost.Test-speak over the years. > #define BOOST_TEST_LOG_LEVEL "message" BOOST_TEST_LOG_LEVEL is supported as an environment variable, not as a macro. Supporting it as a macro would be a bad idea for similar reasons as above - the layout and volume of the output should be for the *user* to control not the author of the tests, or otherwise the user can't rely on what the test output is going to look like from one library to the next. If you, personally, always want the log_level to be 'message', then you should set the environment variable BOOST_TEST_LOG_LEVEL permanently on your system. Hope that helps, Pete

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[histogram] [1.72] merge usability patch?
by Hans Dembinski 05 Nov '19

05 Nov '19

Dear release managers, I have a patch in my develop branch for Boost.Histogram which would like to merge to the master for the 1.72 release. https://github.com/boostorg/histogram/commit/d658aff0b09f73d4f0d3b729b13518… It is a rather intrusive patch, hence my question whether I am allowed to merge this. There is no change to the public interface. The patch provides nice compile-time error messages when users make mistakes in using the histogram instead of spilling out internals details as it does now, that's why I think it would be good to have this already in the upcoming release instead of the next after. The patch passes all the tests in the CI (and new tests developed for this feature). Line coverage remains at 100 % for Boost.Histogram, therefore I am confident that applying the patch is safe. Best regards, Hans

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Re: [boost] [Boost-users] Interest in a Unicode library for Boost?
by Zach Laine 02 Nov '19

02 Nov '19

On Fri, Nov 1, 2019 at 3:41 PM Mathias Gaunard <mathias.gaunard(a)ens-lyon.org> wrote: > This email appears to only be addressed to me and not the list, is > that intentional? > I typed this on my phone so maybe things didn't work exactly as I intended. > It was not intentional. > On Fri, 1 Nov 2019 at 16:09, Zach Laine <whatwasthataddress(a)gmail.com> > wrote: > > > Right. Unicode encodes all natural languages that anyone has taken the > time to put into Unicode. I stand by the implication that natural > languages are crazy. > > Natural languages -- and their transliteration to bytes -- are > arbitrary conventions yes, but they're sufficiently consistent to be > used by millions of people in their personal and professional life > everyday. > There are rules, and however alien they might look to someone who only > needs the fairly straightforward ASCII system, they are not crazy, and > have their own reasons. > > > > So then maybe don't use those parts? They're independent; you don't > have to use them to use the Unicode algorithms. > > Separation of concerns, they do appear coupled in the documentation. > That could just be due to the way the documentation is written. > Could be ... could you point to something in the docs that left you with that impression? I explicitly divided up the documentation along the lines of the separation of concerns found in the code -- the string layer, the Unicode layer, and the text layer. I also tried to be explicit that the first is without dependencies, the second does not depend on the first or the third, and that the third depends on the second. > > Clearly you are more capable than I am. It took me a lot longer to do > than 2 months. Why did you never submit this for a Boost review? You were > thinking about it, ~10 years ago, but you never did.... > > The use case for Unicode is quite niche, and I wasn't particularly > interested in working in that niche further. > Any serious natural language processing engine would probably bypass > Unicode and come up with its own heuristics to parse text, and > applications like GUI toolkits or text editors are specialized enough > that they'd probably never use a library which wasn't specifically > designed for their use case in mind. > That leaves everyday programming, which very rarely needs to do > anything with text beyond treating it as a byte stream, and I believe > wanting to impose the heavyweight Unicode machinery systematically > everywhere is a mistake. > > Anyway, I was just mentioning this because there is prior work > (Boost.Unicode) that you apparently never looked at. > Of course being developed for only a short period of time it doesn't > have the same level of polish as your library. > Ok. FWIW, I did know about your library -- I was there for the BoostCon presentation -- and I was looking forward to using it. Ten years later, I did not look at it again, simply because it had been ten years. > >> and that the database itself is not even accessible, > > > > > > That's also intentional. Another goal of the library is to make Unicode > as simple as possible for naive users who just want to do the basics. If I > find requests for any new feature that has a compelling use case, I'll add > that. > > Being able to replace things like std::isalpha etc. is pretty basic I'd > say. > Having an API that tells you a number of properties about a code point > is one of the most useful parts of Unicode. > I agree I the abstract, but I think that there is a real problem that the properties for a given code point are not necessarily consistent across the various Unicode algorithms. For example, there are multiple notions of "number" that are treated differently in the bidirectional algorithm. Moreover, I don't know of a great use case for a boost::text::is_alpha(). Specifically, it seams that if you are looking for alphabetical characters, you are usually doing something like word-breaking, for which there is already an algorithm, doing a regex match, for which is_alpha() is insufficient, etc. I'm open to hearing about such use cases, of course. > > I don't consider 1.5MB for a database containing all human languages in > widespread use on computers to be a ridiculous size, but YMMV. > > I suppose that's reasonable. > I think the Boost.Unicode one was only 500k but that's an old Unicode > version, and I'm not sure it ever had full collation support. > > > > >> > >> It also doesn't provide the ability to do fast substring search, which > >> you'd typically do by searching for a substring at the character > >> encoding level and then eliminating matches that do not fall on a > >> satisfying boundary, instead suggesting to do the search at the > >> grapheme level which is much slower, and the facility to test for > >> boundary isn't provided anyway. > > > > > > I honestly don't know what you mean here. > > I'm not sure how to clarify this better, but I'll try. > > To search for the utf-8 substring "foo" in the utf-8 string "I really > like foo dogs", there is no need to iterate the string per code point > or per grapheme as you do in your examples. You can just perform the > search at the code unit level, then check that the position before and > after the match does not lie inside a grapheme cluster, i.e. they are > on a valid boundary. > What you need to be able to do that is a function that tells you > whether an arbitrary position in your sequence of utf-8 code units > lies at a grapheme cluster boundary or not (which would probably be a > composition of two separate functions, one that test whether the code > unit is on a code point boundary, and one that tests whether the code > point is on a grapheme cluster boundary). This functionality is not > provided. > > This sort of thing is briefly touched upon in Unicode TR#29 6.4. > I see. This seems like it might be really useful to add. I'll open a ticket for it on Github. Zach

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Interest in a Unicode library for Boost?
by Zach Laine 02 Nov '19

02 Nov '19

About 14 months ago I posted the same thing. There was significant work that needed to be done to Boost.Text (the proposed library), and I was a bit burned out. Now I've managed to make the necessary changes, and I feel the library is ready for review, if there is interest. This library, in part, is something I want to standardize. It started as a better string library for namespace "std2", with minimal Unicode support. Though "std2" will almost certainly never happen now, those string types are still in there, and the library has grown to also include all the Unicode features most users will ever need. Github: https://github.com/tzlaine/text Online docs: https://tzlaine.github.io/text If you care about portable Unicode support, or even addressing the embarrassment of being the only major production language with next to no Unicode support, please have a look and provide feedback. I gave a talk about this at C++Now in May 2018, and now it's a bit out of date, as the library was not then finished. It's three hours, so, y'know, maybe skip it. For completeness' sake: https://www.youtube.com/watch?v=944GjKxwMBo&index=7&list=PL_AKIMJc4roVSbTTf… https://www.youtube.com/watch?v=GJ2xMAqCZL8&list=PL_AKIMJc4roVSbTTfHReQTl1d… Zach

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[filesystem] Management of junction on Windows is broken
by Vincent R. 02 Nov '19

02 Nov '19

Hello, I am bit disappointed to see that symlink and junctions are still not really properly handled on Windows with boost (and even with standard MS libs but that's another story.) First my environment: Windows 10, VS2019 16.3.7, boost 1.71 (static, x64). I would like to write a small c++ utility that does not use os dependent code to handle files so filesystem seems a good candidate. Here is what I am doing on Windows: cd "C:\Users\Vincent\AppData\Roaming\Apple Computer\MobileSync" mklink /j Backup E:\Backup So basically I am creating inside C:\..\MobileSync a junction folder that points to my second harddisk E:\Backup Then I am checking that Windows recognize it by entering dir command: 01/11/2019 23:48 <DIR> . 01/11/2019 23:48 <DIR> .. 01/11/2019 23:29 <JUNCTION> Backup [E:\Backup] 0 fichier(s) 0 octets 3 Rép(s) 59 393 630 208 octets libres As you can see I have a junction targeting E:\Backup, so now let's see what happens with boost: fs::path p(_T("C:\\Users\\Vincent\\AppData\\Roaming\\Apple Computer\\MobileSync\\Backup")); sys::error_code ec; if (fs::is_symlink(p)) { fs::path pathTarget = fs::read_symlink(p, ec); } When I display the content of pathTarget I have: L"\\Backup" ie Backup if I decode it into human string I might not understand anything about junction but is it not supposed to return E:\Backup ?? When I look at source code I can see the following lines: /********************** boost_1_71_0\libs\filesystem\src\operations.cpp **************************************/ symlink_path.assign( static_cast<wchar_t*>(info.rdb.SymbolicLinkReparseBuffer.PathBuffer) + info.rdb.SymbolicLinkReparseBuffer.PrintNameOffset/sizeof(wchar_t), static_cast<wchar_t*>(info.rdb.SymbolicLinkReparseBuffer.PathBuffer) + info.rdb.SymbolicLinkReparseBuffer.PrintNameOffset/sizeof(wchar_t) + info.rdb.SymbolicLinkReparseBuffer.PrintNameLength/sizeof(wchar_t)); This is wrong since we need to distinguish between a symlink and a junction folder so here is my contribution : --- a/src/operations.cpp +++ b/src/operations.cpp @@ -201,6 +201,12 @@ typedef struct _REPARSE_DATA_BUFFER { # ifndef IO_REPARSE_TAG_SYMLINK # define IO_REPARSE_TAG_SYMLINK (0xA000000CL) # endif +# ifndef IO_REPARSE_TAG_MOUNT_POINT +# define IO_REPARSE_TAG_MOUNT_POINT (0xA0000003L) +# endif +# ifndef IO_REPARSE_TAG_DEDUP +# define IO_REPARSE_TAG_DEDUP (0x80000013L) +# endif inline std::wstring wgetenv(const wchar_t* name) { @@ -1661,12 +1667,24 @@ namespace detail if (!error(::DeviceIoControl(h.handle, FSCTL_GET_REPARSE_POINT, 0, 0, info.buf, sizeof(info), &sz, 0) == 0 ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::read_symlink" )) + if (info.rdb.ReparseTag == IO_REPARSE_TAG_SYMLINK) + { symlink_path.assign( static_cast<wchar_t*>(info.rdb.SymbolicLinkReparseBuffer.PathBuffer) + info.rdb.SymbolicLinkReparseBuffer.PrintNameOffset/sizeof(wchar_t), static_cast<wchar_t*>(info.rdb.SymbolicLinkReparseBuffer.PathBuffer) + info.rdb.SymbolicLinkReparseBuffer.PrintNameOffset/sizeof(wchar_t) + info.rdb.SymbolicLinkReparseBuffer.PrintNameLength/sizeof(wchar_t)); + } + else if (info.rdb.ReparseTag == IO_REPARSE_TAG_MOUNT_POINT) + { + symlink_path.assign( + static_cast<wchar_t*>(info.rdb.MountPointReparseBuffer.PathBuffer) + + info.rdb.MountPointReparseBuffer.PrintNameOffset / sizeof(wchar_t), + static_cast<wchar_t*>(info.rdb.MountPointReparseBuffer.PathBuffer) + + info.rdb.MountPointReparseBuffer.PrintNameOffset / sizeof(wchar_t) + + info.rdb.MountPointReparseBuffer.PrintNameLength / sizeof(wchar_t)); + } # endif return symlink_path; } I will add more suggestions in a next message because there is no consistency between boost and MSVC approach. I don't know the last c++ specifications but it shouldn't be difficult to have a simple approach;

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