- Boost - lists.preview.boost.org

[variant2] Review
by Damian Jarek 14 Apr '19

14 Apr '19

> - What is your evaluation of the design? Variant2 is clearly a superior replacement for the original variant type in boost - Boost.Variant and would be very useful for libraries in Boost and outside of it that are stuck on C++11/14. I strongly believe that triviality propagation should be supported, especially if Variant2 is to be used as the implementation detail of a type like `expected`. As for the hot topic of valuelessness - based on my experience of how variant types are typically used, I think that an implementation should loudly object at compile-time to any operation that could put it in a valueless state - e.g. if emplacing can throw and the type does not have a noexcept move constructor. However, I see that it could be quite inconvenient for many users and I consider the fallback mechanism currently in variant2 to be a good enough compromise. > - What is your evaluation of the implementation? I reviewed the implementation and it looks great. As a test, I replaced the internal variant type in Boost.Beast(beast::detail::variant) with variant2 to compare it against the private lean variant and against std::variant. In terms of compilation time, I've observed no significant difference between std::variant and variant2 when compiling the Boost.Beast test suite. Both were about 10% slower to compile than beast::detail::variant, which can be attributed to the additional header material which must be parsed by the compiler. In terms of runtime performance, I have not observed a significant difference between the 3 variants in terms of requests/second in a test project I use to optimize Boost.Beast performance. Note that Boost.Beast HTTP serialization makes heavy use of a variant to enable sending an HTTP message in as few write calls as possible. As far as I know, all types stored in the variant were "well behaved", so it did not test the double-buffering cases. > - What is your evaluation of the documentation? The documentation is adequate, however, it could use a few examples for users unfamiliar with the concept of sum types. > - What is your evaluation of the potential usefulness of the library? It is a useful replacement for Boost.Variant in C++11/14 libraries both in Boost and outside of Boost. > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? About 6 hours, most of which where spent on the compilation and runtime benchmarks based on Boost.Beast. > - Are you knowledgeable about the problem domain? I have implemented and used a few variant implementations in embedded code. I have also reimplemented the private and lean beast::detail::variant type on top of Boost.mp11. Conclusion: I recommend that Variant2 is CONDITIONALLY ACCEPTED if: - documentation is extended with usage examples - triviality propagation is implemented

1 0

[gil] Boost.MPL replaced with Boost.MP11
by Mateusz Loskot 14 Apr '19

14 Apr '19

Hi, FYI, Boost.GIL switched from MPL and TypeTraits to MP11 (thank you Peter Dimov!) and C++11 <type_traits>: https://github.com/boostorg/gil/pull/274 This is a significant refactoring and as such it may have introduced bugs. GIL tests coverage had not been 100% and despite we've added numerous new tests, it's still far from complete. Any GIL users out there, if you notice any bugs, please let us know by opening new issue at GitHub or posting to to https://lists.boost.org/boost-gil/ Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

New B2 version, and CI failures.
by Rene Rivera 14 Apr '19

14 Apr '19

As some of you may have noticed, there were some changes to B2 yesterday (4-12). As previously mentioned I merged the start of the B2 C++ engine port to the develop branch. That change included some "improvements" to the building of the B2 executable. One of those improvements may be causing people CI failures. The new build scripts for B2 now respect, and use, the CXX and CXXFLAGS environment variables. As such it means that if you have those set for other reasons it may confuse the B2 build (i.e. bootstrap.sh/bat invocation) and fail that build. If that's the case you will need to clear those variables before invoking boostrap.sh/bat or build.sh/bat. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

4 9

[ASIO] 1.70.0 async_read_until reports undefined symbol with MSVS 2010
by Kenneth Porter 14 Apr '19

14 Apr '19

The following test code (inside #if 1) generates a LNK2019 (unresolved external symbol) with 1.70.0 but links successfully with 1.69.0. Inspecting read_until.hpp, I suspect the problem is with the enable_if expansion being too complex for the older compiler. (Hence the #if0 code which tests the individual conditions, but those seem to work fine.) The same code links with VS2019 and VS2015, and this linked under the previous Boost with VS2010. int _tmain(int argc, _TCHAR* argv[]) { typedef boost::asio::streambuf buftype; #if 0 const bool v1 = boost::asio::is_dynamic_buffer_v1<typename boost::decay<buftype>::type>::value; const bool notv2 = !boost::asio::is_dynamic_buffer_v2<typename boost::decay<buftype>::type>::value; #endif #if 0 void* cond = boost::enable_if< boost::asio::is_dynamic_buffer_v1<typename boost::decay<buftype>::type>::value && !boost::asio::is_dynamic_buffer_v2<typename boost::decay<buftype>::type>::value >::type* 0; #endif #if 1 boost::asio::io_service ios; boost::asio::ip::tcp::socket socket(ios); boost::asio::streambuf buf; boost::asio::async_read_until(socket, buf, '\n', NULL); #endif return 0; }

1 0

[variant2] Review (comparison with other variants)
by Antony Polukhin 14 Apr '19

14 Apr '19

Hi, > - What is your evaluation of the design? Variant2 is very close to the boost::variant and std::variant. The major difference is in treating very rare border case. Let me put it very clear: * I really like the valueless_by_exception() approach of the std::variant. It gives perfectly determinated result in case of an exception during variant assignments, does not dynamically allocate storage and does not double the size of the variant variable. * The approach of existing boost::variant is not perfect. Exception during assignment could lead to the default construction of some type that was not previously held in the variant. This is actually a very creepy behavior: variant<foo, foo2, locked_mutex> v; v = foo2{}; // may suddenly lock a mutex via locked_mutex{} But users do not complain about this. Exceptions during assignments are so rare, that they just don't get hit by the issue. You have to try really really hard to get into the valueless_by_exception() state. The other drawback of boost::variant is that it dynamically allocates memory in some cases that are also quite rare. * Variant2 fixes the second drawback of boost::variant (dynamic allocations). But the first one is still there - in exceptional cases it may default construct something unexpected. Variant2 also may get performance issues because of the doubled size. Smaller data structures better fit the CPU caches. Some platforms allow returning small variables in registers (not on the stack). On some platforms addressing the first ~127 bytes of the structure is more efficient than addressing the other bytes. Increasing the size of a variant2 for dealing with cases that mostly never happen seems unreasonable to me. I'm not saying that the current boost::variant is perfect in border cases (it is not!). I'm saying that std::variant has no such drawbacks at all. Variant2 keeps some issues of the boost::variant and adds new ones. > - What is your evaluation of the implementation? Looks great. Enjoyed it. > - What is your evaluation of the documentation? Did not read very carefully. > - What is your evaluation of the potential usefulness of the library? Useful only if it will get as good as, or better than std::variant. > - Did you try to use the library? With which compiler(s)? Did you > have any problems? Have not used it. > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? Quick reading. > - Are you knowledgeable about the problem domain? Yes. I maintain the boost::variant and keep an eye on std::variant implementations. Conclusion: I would recommend to REJECT the Variant2 library in it's current state. My opinion would change if the underlying design changes in favor of explicit valueless_by_exception() state. -- Best regards, Antony Polukhin

1 0

Re: [boost] [variant2] Formal review
by Bjorn Reese 14 Apr '19

14 Apr '19

On 4/13/19 7:26 PM, Bjorn Reese via Boost wrote: > Better compiler error messages would be desirable. For instance, if we > use an illegal visitor that has different return types, then the > compiler error does not give us any hint about the different return > types. A possible solution is to declare a tag and use this in the else-part of mp_if. E.g. struct return_types_must_be_the_same; template<class L> using front_if_same = mp11::mp_if<mp11::mp_apply<mp11::mp_same, L>, mp11::mp_front<L>, return_types_must_be_the_same>;

1 0

crc.hpp:569 msvc warning C4800
by Kenneth Porter 13 Apr '19

13 Apr '19

<https://github.com/boostorg/crc/pull/2> Visual Studio 2010-2019 issue this warning for crc.hpp line 569: warning C4800: "'int' : forcing value to bool 'true' or 'false' (performance warning) bool const quotient = remainder & high_bit_mask; Replace with: bool const quotient = (remainder & high_bit_mask) != 0;

1 0

[build] Bootstrap failures in Appveyor CI
by Andrey Semashev 12 Apr '19

12 Apr '19

Hi, I'm seeing multiple Appveyor job failures at bootstrap stage, here's an example: https://ci.appveyor.com/project/Lastique/winapi/build/job/qnu5dhfcpjx3vh1y The code did not change for quite a while and it was passing before. It first failed after the jobs were triggered by the 1.70 tag. Only some of the jobs have failed, and after I re-ran the jobs, a different set of jobs failed the second time. Is this something related to Boost.Build or superproject?

2 1

[release] Boost 1.70.0
by Marshall Clow 12 Apr '19

12 Apr '19

Release 1.70.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains numerous enhancements and bug fixes for existing libraries. For details, including download links, see < http://www.boost.org/users/news/version_1.70.0> You can also download directly from: < https://dl.bintray.com/boostorg/release/1.70.0/source> SHA-256 sums: ae2bb1b35d1f238e72e3f819b42336f4bd27c9ed2092aab5d87818ccb0c9161a boost_1_70_0.7z 430ae8354789de4fd19ee52f3b1f739e1fba576f0aded0897c3c2bc00fb38778 boost_1_70_0.tar.bz2 882b48708d211a5f48e60b0124cf5863c1534cd544ecd0664bb534a4b5d506e9 boost_1_70_0.tar.gz 48f379b2e90dd1084429aae87d6bdbde9670139fa7569ee856c8c86dd366039d boost_1_70_0.zip To install this release on your system, see < http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team Vladimir Prus, Marshall Clow, Daniel James, Micheal Caisse

4 3

[release] 1.71.0 open for merging
by Marshall Clow 12 Apr '19

12 Apr '19

The master branch is open for merging all stable changes from develop, including bug fixes and major upgrades to existing libraries. Breaking changes should be coordinated via the mailing list with the developers of the other libraries affected. New libraries may be added, but require permission of a release manager. In other words, merging does not require permission from a release manager, except for new libraries. Boost Calendar with the release schedule: http://www.boost.org/development/index.html Release schedule explanation: https://github.com/boostorg/boost/wiki/Release-Schedule Release practices for developers: http://svn.boost.org/trac/boost/wiki/ImprovingPractices -- The Boost Release Team

1 0

[variant2] Gavin's review
by Gavin Lambert 12 Apr '19

12 Apr '19

This is my review of Variant2. I vote to ACCEPT this library. However I find the ambiguous state of "expected" a bit too ambiguous (and the "expected" concept in general has caused quite a bit of discussion and contention in the past) so I would prefer that it not be considered part of the library as is, and go through at least a mini-review before entering Boost. I'm not suggesting that this be a formal acceptance condition, however. (I did not look at this type for my review.) I also question whether a more descriptive name than "Variant2" can be used for it, although I recognise that at least starting the library name with "variant" is a good idea to aid discoverability in alphabetic sorting order. - What is your evaluation of the design? As I've stated elsewhere, I feel that if you're willing to pay the cost of double-buffering then you might as well go all-in and implement the strong guarantee as well (or at least a partially strong guarantee, where any attempt to change the stored type provides the full strong guarantee but attempts to assign the same type merely delegates to the underlying type's assignment operation and so provides the same guarantee as that -- this seems sufficiently reasonable and useful to me without sacrificing too much performance, and still lets you single-buffer as an optimisation when all types are noexcept assignable). Having said that, I recognise that others have different lines in the sand, and this is a reasonable design choice within those lines. - What is your evaluation of the implementation? Overall, good. I do have a few minor nitpicks: 1. bad_variant_access's constructor should be "constexpr = default" to preserve constexpr and/or triviality (if std::exception is also constexpr and/or trivially constructible, although this is not the case in VS2017, but could be in other implementations). 2. When std::monostate exists, it should treat both equivalently, for compatibility. (It should not alias its own to std::monostate, as that poses ABI problems if not all code is compiled in C++17 mode.) 3. The duplicated include guard around <boost/mp11.hpp> seems both ugly and unnecessary. Also it should probably be included after <boost/config.hpp>. 4. It's not clear why some of the internal methods (such as _get_impl) have leading underscores while others (such as emplace_impl) do not. It seems inconsistent. 5. It's not clear what purpose the "none" storage type serves (other than apparently requiring the indexing to be offset by one). It seems rather like an empty state... (and the continual offsetting seems inefficient; most of it happens at compile time, but not all). 6. variant_base_impl::_replace has a "requires" comment; why doesn't it have a matching assert? Also, why are these not BOOST_ASSERTs? 7. As discussed elsewhere, a public trait should be provided which lets you static_assert which implementation was actually instantiated. - What is your evaluation of the documentation? It is minimal but sufficient for readers already familiar with std::variant. (And who can read standardese.) It is not sufficient for readers not familiar with std::variant. I think this is mostly fine, but I would prefer the addition of a Motivation and/or Design Rationale section which explains why this is better than std::variant and boost::variant. In future it would also be nice to have a Porting section which explains what code changes are required to move from those to this. - What is your evaluation of the potential usefulness of the library? It seems potentially useful for others, although I would personally have preferred different design choices. - Did you try to use the library? With which compiler(s)? Did you have any problems? I did not try it. - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? I read through the documentation and code in moderate detail, but not in-depth. - Are you knowledgeable about the problem domain? I am familiar with variants, but have not as yet used them much in production code.

1 0

Variant2 review
by Phil Endecott 11 Apr '19

11 Apr '19

Dear All, Here is my brief review of Peter Dimov's proposed Boost.Variant2. Sorry that this is not a particularly thorough review. I have read the docs, scanned the code, and followed the discussion on the mailing list; I have not tried to compile or use it. I have recently been using the original Boost.Variant for the first time. I actually started writing code based on std::variant, but then realised that I don't have support for it on one C++14-only platform, so changed to Boost.Variant. It's unfortunate that Boost.Variant has a somewhat different interface from std::variant, so it would be useful to have a Boost variant that is (more) compatible with std::variant. It would also be useful if it were somewhat backward compatible with the old Boost.Variant. The proposed Boost.Variant2 is compatible with std::variant; could some thin layer of compatibility be added to make it possible to port from Boost.Variant code? Specifically, the differences I have noticed are apply_visitor vs. visit and get(V*) vs. get_if. In my case, my stored types are typically raw pointers or small POD structs; none of these can throw during construction/assignment so the complicated arguments about exception guarantees are not applicable. Personally for my current application I'd be happy with a simpler variant that requires noexcept types, or disables assignment for types that might throw, or just doesn't offer an exception safety guarantee. Ideally, perhaps a Boost.Variants *library* should provide a selection of different variants with different features? That leads to the question of naming; we have boost::variant, boost::variant2 and std::variant and those names tell us nothing about how they differ. I'm unsure how or if this can be improved; I'm not suggesting that variant2 should be renamed variant_never_empty_maybe_double_size! But maybe the long-name of the library, i.e. what people will see when they look at the list of Boost libraries, could say "Never empty variant" rather than "Variant 2"? Prior to the review I was familiar with the issue of dynamic allocation, the fact that is is needed in some cases by some variant implementations, and the desire to avoid it. However I was not aware of the alternative of storing two copies of the union, doubling the size of the variant. Much of my work is with memory-constrained systems and unknowingly using twice as much memory as expected would be very undesirable. (I noticed Niall Douglas' comment earlier today "There is nothing wrong, *whatsoever*, with a variant which is sized the largest of its possible states multiplied by two" - I strongly disagree with that.) I'd like to at least get a warning if that were going to happen. A specific concern is that I might accidentally get this fallback due to forgetting to write "noexcept" somewhere (e.g. when using types from older code). On the subject of size, I note that the index is stored in an int, while virtually all uses would surely need fewer than 256 (or certainly 2^16) alternatives. Of course changing the index to uint16_t would not actually help on many platforms due to structure alignment requirements. This makes me wonder about a specialised variant for pointers that uses the spare bits in (most/some) 64-bit pointers to store the variant index. This could usefully be part of a variants *library*. I read Andrzej Krzemienski's comments about the documentation and largely agree with them - though I would say that this library is close enough to std::variant that perhaps the right thing to do is simply to say "go and read about std::variant and then come back here to see the differences". Peter posted a link to some benchmark results last week; those numbers are encouraging and it is also good to know that Peter actually made the effort to measure them! I do wonder how a "trivial" variant supporting only noexcept types would compare, though. Boost.Variant has something called polymorphic_get. I am unclear whether Boost.Variant2 (and/or std::variant) somehow support this functionality. The situation re. expected is unfortunate. I believe really the review should have waited for it to be completed. Peter's comment that if it is decided that it needs to be reviewed then he would remove it and never resubmit it was ... surprisingly undiplomatic? I have always found it a bit odd that Boost requires a thorough review of an initial library submission but nothing at all for later additions. In summary: - I believe the library should be accepted. - It would be great if some compatibility features with Boost.Variant could be added, to make it possible for users of that older library to transition more easily. That is not a condition for acceptance. - I would love to have some way to get a warning or error if the double storage mode had been triggered, or to disable that mode (with an error). - It would be great to see some alternative variants, with different features / trade-offs, included in the library. Ideally, naming of types and headers should allow for that. I'm not suggesting that Peter should be personally expected to supply these alternatives, but perhaps he would accept offerings from others. - I think we should allow Peter to "slip in" his expected when it is ready; I say this largely because Peter has a long history with Boost. Future review managers should try to avoid situations like this arising. Regards, Phil.

7 18

[release] Boost 1.70.0 Release Candidate 2 available
by Marshall Clow 11 Apr '19

11 Apr '19

The second release candidate for the 1.70.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.70.0/source/> Changes since rc1: * Boost.Config changes to work better with msvc-14.2 * Boost.Beast bug fixes * Boost.Move bug fix * Boost.Math non-ascii characters removed from header file The SHA256 checksums are as follows: 882b48708d211a5f48e60b0124cf5863c1534cd544ecd0664bb534a4b5d506e9 ./boost_1_70_0_rc2.tar.gz 430ae8354789de4fd19ee52f3b1f739e1fba576f0aded0897c3c2bc00fb38778 ./boost_1_70_0_rc2.tar.bz2 48f379b2e90dd1084429aae87d6bdbde9670139fa7569ee856c8c86dd366039d ./boost_1_70_0_rc2.zip ae2bb1b35d1f238e72e3f819b42336f4bd27c9ed2092aab5d87818ccb0c9161a ./boost_1_70_0_rc2.7z As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

3 5

Problem with generating file_descriptor suing existing pipe file descriptor
by Russell West 10 Apr '19

10 Apr '19

Our program just installed version 69 of Boost and I am running into a compile issue that I am not sure how to resolve. Following is the associated section of C++ code that I am unable to figure out the changes to get it to compile. int filedes[2]; if ( pipe(filedes) == 0) { using namespace boost::iostreams; stream<file_descriptor> results(filedes[0], close_handle); .... .... } The last provided line of code does not compile with a no matching function for call to 'boost::iostreams::file_descriptor::file_descriptor(int&, file_descriptor_flags&)' error. I noticed in the version of the boost file_descriptor.hpp loaded and being used the following exists: #ifdef BOOST_IOSTREAMS_WINDOWS file_descriptor(int fd, file_descriptor_flags); #endif The associated application attempting to be built and deployed is only for servers running the Linux operation system so BOOST_IOSTREAMS_WINDOWS is not enabled, causing the above constructor not to be available. The other constructor available is file_descriptor(handle_type fd, file_descriptor_flags); but I can not figure out how to generate a detail::file_handle from the available int file descriptor generated from above pipe command. Will it cause any issues enabling BOOST_IOSTREAMS_WINDOWS so the required constructor will be available? Thanks ahead of time for your time and feedback. Russell West

2 1

Re: [boost] [Boost-GIL] Image Processing Algorithms
by Mateusz Loskot 10 Apr '19

10 Apr '19

On Wed, 10 Apr 2019 at 18:54, Amir Ali <amirqadir(a)live.com> wrote: > > I really want to do this project even if I am not considered for GSOC. > I am still willing to do it on my own with guidance and supervision from any mentor. There are two mentors who will mentor three students in total. So, we can not offer any supervision to more projects. You are welcome to post your questions to the boost or boost-gil lists, or ask on Gitter room or the Slack channels as any user of / contributor to Boost libraries can do. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

[Boost-GIL] Image Processing Algorithms
by Amir Ali 10 Apr '19

10 Apr '19

Hi, I am looking for someone to mentor me for my project that is to implement image processing algorithms in Boost-GIL. Here’re some of the algorithms I am aiming to make. Mathematical Morphology (Dilation, Erosion, Opening, Closing) Filters (High pass Filters, Low Pass Filter which includes Gaussian etc) And Other Image enhancement basic algorithms. Regards Amir

2 1

[variant2] Andrzej's review -- documentation
by Andrzej Krzemienski 10 Apr '19

10 Apr '19

Hi Everyone, This is the review of the documentation of variant2. First, the docs assume that the user is already familiar with std::variant or boost::variant, and the introductory part only highlights the difference from std::variant. It does not even mention that variant<X, Y> always stores either X or Y. "Type-safe discriminated union (variant) type," sounds arcane to novices. Notation variant<T…> is also confusing to someone who encounters variant for the first time. There is no initial example. No mention of visit() which is the most important part of the interface. Compare this with Boost.Variant docs: https://www.boost.org/doc/libs/1_69_0/doc/html/variant.html I do not think the library should assume this. Boost libraries are characteristic of documentation that introduces potential users to the problem domain and gives a sort of tutorial that shows how to use the library. I recommend doing the same for variant2. This library does a lot of contortions to avoid the valueless state, but does not describe what the motivation for it is. The docs also do not give a sense of what performance (spacial and runtime) trade offs this library does. For instance, we do not know if the double-buffer scenario th second buffer is within variant's storage or on the heap. Or we do not know about secret moves that the library does internally, which gives surprising behavior to the users that store non-movable types in variant. Consider the following example: ``` struct X {}; struct Guard { explicit Guard(int) {} Guard(Guard&&) = delete; }; variant<X, Guard> v {}; v.emplace<Guard>(1); ``` This works fine with std::variant, but fails to compile with variant2::variant, because the latter requires all the alternative types, at least in one implementaiton of the never-empty trick, to be move-constructible. But this requirement is never listed in either global requirements for alternative types stored in variant, or in the specification of functions `emplace()`. Here's a wandbox example: https://wandbox.org/permlink/hGbRtgzpUrpF0ODy The Reference part of the docs is really good and detailed. Some minor "bug reports" follow. In the specification of functions types `T0` and `Ti` are used, but `T0` or `Ti` are never defined. Wording in the C++ Standard also refers to `T0` and `Ti`, but also provides a definition: In the descriptions that follow, let i be in the range [0, sizeof...(Types)), > and Ti be the ith type in Types. > <http://eel.is/c++draft/variant.ctor#1.sentence-1> > See http://eel.is/c++draft/variant.ctor#1 A similar definition should be put in variant2's documentation. Noexcept specifications use mp_all. this assumes that users of variant2 must be familiar with Boost.mp11. I recommend removing the reference to mp_all and instead use something similar to what the Standard does: http://eel.is/c++draft/variant.ctor#11 Specification of function `emplace()`: It says: > > On exception: If the list of alternatives contains monostate, the > contained value is either unchanged, or monostate{}; > In what situation on exception is the contained value left unchanged? This question applies to the next bullet as well. The specification also doesn't mention that `.emplace()` requires Ti to be move-constructible in some cases. It also says: Throws: Nothing unless the initialization of the new contained value throws. Which sounds strange, because it does throw something. In other places you use "Throws: Any exception thrown by the initialization of the contained value.", which makes more sense. Also, the Standard uses, "Throws: Any exception thrown during the initialization of the contained value. <http://eel.is/c++draft/variant.mod#11.sentence-1>": http://eel.is/c++draft/variant.mod#11 swap(): What does it throw and when? Other functions specify it but this one does not. get(): Specification says, > > If v.index() is I, returns a reference to the object stored in the > variant. Otherwise, throws bad_variant_access. > This means that if I provide an index that is far greater than `sizeof...(T)`, the program should compile fine and throw an exception at run-time. This is not what the implementation does: I get a compile-time error, which is good, but inconsistent with the docs. They need an additional "Requires:" clause. visit(): I think it is underspecified. It is not immediately clear that the first parameter is the visitor and the remaining ones are variants. Parameter names F and V do not convey this clearly. Either use Visitor and Variants... or provide a longer description, even if informal. The docs really should contain an example of `visit()` somewhere. According to the specs, the following should work: ``` void f() {} variant2::visit(f); ``` which is not incorrect, but strange. The std::variant also provides a second overload of `visit` that explicitly defines the return type: http://eel.is/c++draft/variant.visit This overload is not present in variant2. But this fact is not listed in the initial section of the docs that lists the differences between the two libraries. Regards, &rzej;

2 6

[variant2] Comments on documentation
by Bjorn Reese 10 Apr '19

10 Apr '19

The overview states that "variant<T...> is not trivial when all contained types are trivial". Why not? Is this an advantage somehow or an unfortunate limitation? Why is there no tutorial? Why is there no design rationale? Change "variant_npos = -1" into "variant_npos = unspecified" Add a comment about the purpose of valuesless_by_exception(). Without such a comment, the function seems very odd on a "never valueless variant type." The destructor should be marked as noexcept.

4 8

[variant2] Review - Review period extended until April 15
by Michael Caisse 09 Apr '19

09 Apr '19

Hi all - The review period for Boost.Variant2 has bee extended to April 15. Thank you to those who have participated so far. There has been a fair amount of discussion about the merits of never valueless. A core design _feature_ of Variant2 is never valueless. You may have made different trade-offs. Understanding motives makes sense but in this review we are not trying to change this basic design choice. This paper by Peter discusses valueless variants some and may be useful reading: <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0308r0.html> If you haven't started your review yet, you have time! Reviews ranging from detailed discussions of inner workings to a user-perspective of the library and documentation are all helpful. I personally believe we need more user-based reviews in Boost. So, feeling sheepish about reviewing? Don't! Your review is important in the process. Here is one more motivation if you are on the fence ... Peter's code is a joy to read. The library is extremely clean and the code is accessible. There might be all kinds of things you learn from reading the source. Thank you again community for staying involved. We get great libraries when people ask questions, review, and provide input to everything from the docs to the design. Happy coding! michael -- Michael Caisse Ciere Consulting ciere.com

1 0

GSOC 2019 proposal
by Siddhartha Sen 09 Apr '19

09 Apr '19

Once the proposal is ready, where do I officially submit the pdf?

2 1

Re: [boost] [release] Boost 1.70.0 Release Candidate 1 available
by Ion Gaztañaga 09 Apr '19

09 Apr '19

On 07/04/2019 15:07, Rainer Deyke via Boost-users wrote: > On 07.04.19 14:13, Marshall Clow via Boost-users wrote: >> On Sat, Apr 6, 2019 at 10:53 AM Rainer Deyke via Boost-users < >> boost-users(a)lists.boost.org> wrote: >> >>> On 04.04.19 16:27, Marshall Clow via Boost-users wrote: >>>> As always, the release managers would appreciate it if you download >>>> the candidate of your choice and give building it a try. Please report >>>> both success and failure, and anything else that is noteworthy. >>> >>> boost::movelib::adaptive_merge continues to be broken if >>> iterator_traits<RandIt>::size_type != std::size_t. This breaks >>> boost::container::flat_map when cross-compiling for MacOS. I have >>> previously reported this error here. >>> >>> I consider this a critical error - as in, I won't be able to upgrade to >>> Boost 1.70 at all unless this error is fixed for the release. >>> >> >> This is https://github.com/boostorg/move/issues/25, correct? > > Yes. Sorry for note replying earlier, I was on a trip. The fix is not complicated but several files need to be modified. Committed to develop: https://github.com/boostorg/move/commit/bfdfca0b88fe1cf4e67b42fcacd5e126e93… @Rainer: I've checked this fix in several msvc and gcc's locally. The error report does not contain any example for the bug, so I don't know if I've fixed your use case. I don't know if we are still on time for 1.70. Best, Ion

4 5

[variant2] request to extend the review period
by Andrzej Krzemienski 08 Apr '19

08 Apr '19

Michael, Peter, Would it be possible to extend the review period? I may only be able to devote more time to the review on Thursday, so if it was possible to extend the review at least till 12th, I might have a chance to get it done. I suspect, I might be not the only one in this situation. Regards, &rzej;

1 0

Re: [boost] variant - off topic
by Bjorn Reese 08 Apr '19

08 Apr '19

On 4/3/19 11:27 PM, Robert Ramey via Boost wrote: > d) insert your own use case here. That is, look at your own usages of > assignment to these types and see if there is not an easy way to > re-factor your code to avoid assignment. Such refactoring is difficult for state machines where you use a variant to denote the current state.

4 9

Enabling spectre mitigation in boost libraries
by Riff J 08 Apr '19

08 Apr '19

Hi everyone, I am a developer from Microsoft and currently using boost in our project. We recently get noticed by our security team, that the boost library we use, are not compiled with spectre mitigation (/Qspectre) enabled. Since boost is super powerful, it might not be a good idea to write our own or maintain our own version, so we are reaching out for help. Could anyone please help see if we could enable /Qspectre option in the official build of boost? And here is the vcblog about the spectre mitigation, if anyone is interested: https://blogs.msdn.microsoft.com/vcblog/2018/01/15/spectre-mitigations-in-m… . And since this is the first time I use this mail list, please let me know, if I didn't use it correctly or anything I should pay attention to. Thanks a lot, Riff

10 22

[gsoc19] Boost.Geometry Delaunay triangulation and Voronoi diagrams
by Georgios Venizelos 08 Apr '19

08 Apr '19

Hello, I would like to undertake the Delaunay/Voronoi project in Boost.Geometry library. I have already shared my proposal on GSoC through Google Docs. I think that Delaunay triangulation is a process that has many applications, so it is useful to have such a process implemented in Boost libraries. Main focus of the program would be to implement Delaunay and Voronoi for Cartesian coordinates in 2 and 3 dimensions. If finished early, this could extend either in higher dimensions or in other coordinate types. Would anyone be interested in mentoring such a GSoC project? With respect, Georgios Venizelos --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

1 0

Re: [boost] Enabling spectre mitigation in boost libraries
by Kenneth Porter 08 Apr '19

08 Apr '19

On 4/6/2019 9:46 AM, John Maddock via Boost wrote: > One thing we could look at for future releases would be to provide > differently-named binaries for /Qspectre. Anyone else have thoughts > on that? I just looked at the libraries available via the Visual Studio installer and I see this in my installation (using atls as an example MS-supplied library): C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\atlmfc\lib\spectre\x64\atls.lib C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\atlmfc\lib\spectre\x86\atls.lib C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\atlmfc\lib\x64\atls.lib C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\atlmfc\lib\x86\atls.lib That may give some guidance as to how MS can package the Boost libraries for internal distribution.

1 0

Re: [boost] [variant2] Andrzej's review -- design
by Mike 08 Apr '19

08 Apr '19

> Going back to variant, in one case, we are defining an empty state, which > forces the user to provide explicit handling for that state, *everywhere*. You keep repeating that the user would have to explicitly handle that everywhere. I thought I just showed you that this is not the case. Except for visit, you don't have to explicitly handle the valueless state at all and even in the case of visit, you might be fine with std::visit just throwing an exception, because that is indeed an exceptional circumstance. I don't see this *everywhere* at all. Best Mike

8 18

[release] Master branch now completely closed for the 1.70.0 release
by Marshall Clow 08 Apr '19

08 Apr '19

The master branch is now closed for all changes except by permission for the release. Also, remember to add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_70_0.q… > Thanks, -- The Boost Release Team

4 7

Regarding Boost.Astronomy GSoC19 proposal review
by sarthak2007 07 Apr '19

07 Apr '19

Hello community, I am Sarthak Singhal, pursuing B.Tech in Computer Science from Indian Institute of Technology, Kanpur. I had submitted the programming competency test to mentor and also got a positive response from her. I had also submitted the project proposal to the mentor and based on her suggestions have improved it also. I have submitted the draft of the proposal to GSoC site. I request you to go through the proposal. I will appreciate your feedback to improve the proposal. Thank you, Sarthak Singhal -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

2 4

[release] Boost 1.70.0 Release Candidate 1 available
by Marshall Clow 07 Apr '19

07 Apr '19

The release candidates for the 1.70.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.70.0/source/> The SHA256 checksums are as follows: 6e5cba1269225395bb5e78dda48441ccadaf745e42638180015e9e6257068336 ./boost_1_70_0_rc1.7z 35d8e1361e2063f70aa3a6ca0dd8af0877ceb75477ebbd2c726bb1d039658c7a ./boost_1_70_0_rc1.tar.bz2 ec8ddbbee2fd61e2f78a1dfe9a07ad83ca8f6a2f4c704d6f297d89c6afdc4f2c ./boost_1_70_0_rc1.tar.gz ee2c3b97ce10f85a31b6a105ad8edf1c20fb4b936c9a6e6008206059cb98ab1b ./boost_1_70_0_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

7 14

Re: [boost] [Boost-users] [release] Boost 1.70.0 Release Candidate 1 available
by Marshall Clow 07 Apr '19

07 Apr '19

On Sat, Apr 6, 2019 at 10:53 AM Rainer Deyke via Boost-users < boost-users(a)lists.boost.org> wrote: > On 04.04.19 16:27, Marshall Clow via Boost-users wrote: > > As always, the release managers would appreciate it if you download > > the candidate of your choice and give building it a try. Please report > > both success and failure, and anything else that is noteworthy. > > boost::movelib::adaptive_merge continues to be broken if > iterator_traits<RandIt>::size_type != std::size_t. This breaks > boost::container::flat_map when cross-compiling for MacOS. I have > previously reported this error here. > > I consider this a critical error - as in, I won't be able to upgrade to > Boost 1.70 at all unless this error is fixed for the release. > This is https://github.com/boostorg/move/issues/25, correct? -- Marshall

1 0

[gsoc 19] Review of the proposal draft
by pranay gupta 07 Apr '19

07 Apr '19

Hi list, I have submitted the first draft of my proposal for implementing non-negative matrix factorisation in boost.ublas. It would be really helpful if you could please review it and suggest any improvements. Thanking you in advance. Sincerely, Pranay

2 3

Variant2 review
by Niall Douglas 07 Apr '19

07 Apr '19

I'll firstly apologise for the brevity of this review. It is just before the ACCU conference where I am speaking on a topic I have little knowledge of, and I have done almost no prep due to insufficient hours in the day. I am aware that if I don't make a review now, then I won't at all, so this will have to do. 1. Overall I like the library, it adds significant benefit (primarily removal of dynamic memory allocation) over Boost.Variant. 2. I don't like the lack of propagation of triviality of each individual special member functions. std::variant does this. std::expected does this. I can see Peter's point that for long lists of alternative states, implementing this is a lot of pain for almost no gain. However I do NOT agree with him for Expected. For a two-state variant, it is very highly likely that triviality of special member function will be very important for not a small number of use cases. I personally am happy for Variant2 to implement Expected without review approval here IF that Expected matches exactly std::expected. I am NOT happy if Variant2's Expected breaks conformance on triviality of special member function. If that is the only option on the table, then either please do not include an Expected implementation, or don't include Variant2. This raises a wider point though. What is good for a two-state variant still applies, though less so, to three-state variants, four-state variants and so on. I think there is a fundamental design issue here. If Variant2 can't propagate triviality of individual special member functions for small-number-of-state variants, then there is something fundamentally wrong here. 3. I find the design choice to randomly permute state to avoid an empty state baffling when there is a double buffer based design choice available. I do not like, one bit, the random permutation of state. I think it will lead to buggy code with hard-to-test corner cases. I think it needs to go away in the proposed design. I also don't get the dislike of the double buffer based design. Peter seems to really dislike it, and avoids it whenever possible. I can't understand why. If you can employ a double buffer design in order to eliminate random permutation of state, to me this is an unalloyed good in every way. Nowhere does it say that a variant must be no larger than the largest of its possible states. There is nothing wrong, *whatsoever*, with a variant which is sized the largest of its possible states multiplied by two. So please change the design to that instead. That should be the default design, and design claims. Programmers should write code assuming that design. IF it can be proven that a double buffer is unnecessary e.g. all alternative types are noexcept, a monostate alternative is available etc, THEN you can employ a single buffer implementation as an *optimisation*. That makes thing simple for the end user: add monostate, get single buffer sized. Otherwise assume double buffer sized. With a default double buffer design, most of the other issues which other reviewers have raised go away. Even Robert's concerns about assignment operators, with a double-buffer-by-default design one can always implement the strong guarantee. I badly need to depart, so I'll have to end there by saying that I vote to ACCEPT, conditional on (i) propagation of triviality of special member functions for at least small numbers of alternative states and (ii) removal of ANY POSSIBILITY of random permutation of chosen state under ANY circumstances. Finally, thanks Peter for bringing this library for review. Nice library. Niall

1 0

Proposal for GSoC'19 ( Random Points Generation)
by Mudit Agarwal 06 Apr '19

06 Apr '19

Hi I am submitting my first draft of the proposal for the project, Implementing algorithm for random point generation according to some given distribution in a geometry. I have also implemented competency test for the project https://github.com/Mudit-1999/Random_Points_Generation. It would be really helpful if you could please check if I have fulfilled all the points mentioned to pass competency test. Can you also please review my proposal and suggest any improvement. Hereby attach is my proposal. Thanking you in advance Regards, Mudit Agarwal

1 0

[review][variant2] Variant2 Review Starts April 1
by Michael Caisse 06 Apr '19

06 Apr '19

The Boost formal review of Peter Dimov's Variant2 library will take place April 1 - 10, 2019. Please consider participating in this review. The success of Boost is partially a result of the quality review process which is conducted by the community. You are part of the Boost community. I will be grateful to receive a review based on whatever level of effort or time you can devote. Variant2 is a never-valueless C++11/14/17 implementation of std::variant. >From the README: The class boost::variant2::variant<T...> is an almost conforming implementation of std::variant with the following differences: * A converting constructor from, e.g. variant<int, float> to variant<float, double, int> is provided as an extension; * The reverse operation, going from variant<float, double, int> to variant<int, float> is provided as the member function subset<U...>. (This operation can throw if the current state of the variant cannot be represented.) * variant<T...> is not trivial when all contained types are trivial. To avoid going into a valueless-by-exception state, this implementation falls back to using double storage unless * one of the alternatives is the type monostate, * one of the alternatives has a nonthrowing default constructor, or * all the contained types are nothrow move constructible. If the first two bullets don't hold, but the third does, the variant uses single storage, but emplace constructs a temporary and moves it into place if the construction of the object can throw. In case this is undesirable, one can force emplace into always constructing in- place by adding monostate as one of the alternatives. You can find the source code here: <https://github.com/pdimov/variant2> and the documentation here: <https://pdimov.github.io/variant2/doc/html/variant2.html> Please take an early look at the library and ask questions now. Peter Dimov is very active on the Cpplang Slack #boost channel; however, please consider using the Boost Dev or User Mail Lists so that the entire community might benefit from your conversation. Note: The repository contains an expected implementation also; however, that is not being considered in this review. Thank you for your participation! michael -- Michael Caisse Ciere Consulting ciere.com

5 12

[gsoc19] looking for mentor
by Aziz Mousa 06 Apr '19

06 Apr '19

hi, I have my idea to contribute in boost project, I read the boost libraries list and see that the author of Algorithm is "Marshall Clow" I want to know how to contact with him to tell him about my idea. thanks.

1 0

Call for Speakers: International Conference on Information Society (i-Society 2019)
by International Conference on Information Society 06 Apr '19

06 Apr '19

If you are not able to see this mail, click http://r.confinfosoc.org/mk/mr/qLUGBQMxp4Sjs2NE4YExi3z5lvlWCZKGhXcL8vLsIM2b… for Speakers: International Conference on Information Society (i-Society 2019) [ ]( http://r.confinfosoc.org/mk/cl/f/SUXNTtBZKKIQS3K7XMAgqz2d4gwN08R7QeY-JpBOAY… ) Submission i-Society 2019 Call for Speakers is an open invitation. We sincerely hope that you could give a talk to the diversity of participants. Increase numbers of renowned speakers have confirmed their participation. If you are interested in giving a talk, please complete the form at http://r.confinfosoc.org/mk/cl/f/WcSYgytshsQLNmvIxy3wVH45pNQcePlyBDtX1_3wdq… before or by the 1st of May, 2019. [ Submission ]( http://r.confinfosoc.org/mk/cl/f/-hT6brTC-Gpj8JwZIfXWMoq1tq9fO0kmb4uz_A4rSS… ) This email was sent to boost(a)lists.boost.org You received this email because you are registered with Infonomics Society [ Unsubscribe here ]( http://r.confinfosoc.org/mk/un/IcFogLSqu5RwSkorQ9Mu-bTdNLGBdU-QcdZpGWjlqfqJ… ) Sent by [ ]( http://r.confinfosoc.org/mk/cl/f/3aG3a0Qf4pxEQF2aHlpkSK0PjUVKbrOE2FXQYnchXN… ) © 2019 Infonomics Society

1 0

auto_link.hpp update for Visual Studio 2019 GA release
by Trueman, Chris 06 Apr '19

06 Apr '19

Building boost with the GA release of Visual Studio 2019 names the outputs with v142 (which matches what VS 2019 names its build tools). But auto_link.hpp causes the linker to look for files named with v141. I changed auto_link.hpp to: # elif defined(BOOST_MSVC) && (BOOST_MSVC < 1910) // vc14: # define BOOST_LIB_TOOLSET "vc140" # elif defined(BOOST_MSVC) && (BOOST_MSVC < 1920) // vc14.1: # define BOOST_LIB_TOOLSET "vc141" # elif defined(BOOST_MSVC) // vc14.2: # define BOOST_LIB_TOOLSET "vc142" This corrected the linker errors on my machine. I'm happy to submit this properly but thought I'd check it with folks here first. Chris. INTELLICORP LEGAL NOTICE: This E-Mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying or other use of this message or its attachments is strictly prohibited. If you received this message in error, please notify the sender immediately by replying to this message, and then delete it.

1 1

GSoC'19 [Boost.Geometry : Implementing algorithms for the concave hull problem]
by yaghyavardhan singh khangarot 06 Apr '19

06 Apr '19

Hi, I am interested in contributing to Boost.Geometry and would like to work on the Project 1 (Implementing algorithms for the concave hull problem) as my GsoC’19 project. I had some discussion regarding this with Adam Wulkiewicz. I have read the paper ( Moreira, Adriano J. C., and Maribel Yasmina Santos. “Concave hull: A k-nearest neighbors approach for the computation of the region occupied by a set of points.”) and currently going through the paper “A New Concave Hull Algorithm and Concaveness Measure for n-dimensional Datasets*” ( https://www.iis.sinica.edu.tw/page/jise/2012/201205_10.pdf )) . These are the papers given in the project description. I am also searching for any other algorithms (newer or better) for the concave hull problem. Please direct me to any other algorithms related to this project. Regards Yaghyavardhan

2 3

[GSOD19] Mentors registration
by Damian Vicino 06 Apr '19

06 Apr '19

Hi, I started the registration process for Google Season of Docs, please contact me if you want to mentor to do the formalities. Each documentor requires 2 mentors in GSOD, so the work will be collaborative. Best regards, Damian Vicino

2 2

Re: [boost] [Boost-users] [release] Boost 1.70.0 Release Candidate 1 available
by Tom Kent 04 Apr '19

04 Apr '19

On Thu, Apr 4, 2019 at 9:27 AM Marshall Clow via Boost-users < boost-users(a)lists.boost.org> wrote: > The release candidates for the 1.70.0 release are now available at: > <https://dl.bintray.com/boostorg/release/1.70.0/source/> > > The SHA256 checksums are as follows: > 6e5cba1269225395bb5e78dda48441ccadaf745e42638180015e9e6257068336 > ./boost_1_70_0_rc1.7z > 35d8e1361e2063f70aa3a6ca0dd8af0877ceb75477ebbd2c726bb1d039658c7a > ./boost_1_70_0_rc1.tar.bz2 > ec8ddbbee2fd61e2f78a1dfe9a07ad83ca8f6a2f4c704d6f297d89c6afdc4f2c > ./boost_1_70_0_rc1.tar.gz > ee2c3b97ce10f85a31b6a105ad8edf1c20fb4b936c9a6e6008206059cb98ab1b > ./boost_1_70_0_rc1.zip > > As always, the release managers would appreciate it if you download > the candidate of your choice and give building it a try. Please report > both success and failure, and anything else that is noteworthy. > Windows/Visual Studio (msvc 10.0, 11.0, 12.0, 14.0, 14.1) builds look good. toolset arch compile Link Execute msvc-10.0 32 X X X msvc-10.0 64 X X X msvc-11.0 32 X X X msvc-11.0 64 X X X msvc-12.0 32 X X X msvc-12.0 64 X X X msvc-14.0 32 X X X msvc-14.0 64 X X X msvc-14.1 32 X X X msvc-14.1 64 X X X Compile means that the b2 command completed without errors Link means that visual studio was able to link a sample executable to a library (libboost_thread-vcXXX-mt[-gd]-1_XX.lib) generated Execute means that the linked program executed without errors. Full build logs can be found at: https://gist.github.com/teeks99/798df332c12ec98708e3710da35dd606 Tom

2 1

[variant2] Andrzej's review -- design
by Andrzej Krzemienski 04 Apr '19

04 Apr '19

Hi Everyone, First of all, I wanted to thank Peter for writing this non-trivial library and sharing it with the community. This is not a full review yet. I just wanted to discuss the design first, especially the never-empty guarantee. And I am going to rehash the old argument. The core of variant2 is its never-empty guarantee and the mechanism to achieve it: a number of different algorithms chosen depending on what the potentially stored types permit. In fact this mechanism is not much different than the one present in boost::variant. The issue to solve is what happens in copy/move assignment of variant<X, Y> when we have to change the stored type from X to Y. X has to be destroyed and Y initialized. But if the initialization of Y throws we would be left without either X (already destroyed) or Y (not successfully constructed). (The same problem applies to member function emplace()). Except for the last step boost::variant and variant2 try to apply the same sequence: 1. If all the subtypes have noexcept initialization, no safety measures need to be taken. 2. If sub-types have noexcept move constructor, a temporary local storage is used and the backup value is moved to and from it. 3. If one of the subtypes is a special type boost::blank or std::monostate respectively, in case of a throw this type is default constructed in the variant. 4. If there is any nothrow-default-constructible subtype in the variant, it gets default-constructed upon exception. If neither of the above can be applied, the two libraries apply different approaches. variant2 is big enough to fit two unions of X and Y within its storage. This way it does not have to destroy the X when initializing the Y. boost::variant, for the additional storage uses heap allocated memory. Interestingly, the double storage as in variant2 has been considered in the initial design of boost::variant but rejected by the community, because it added spacial overhead even for use cases that never invoked variant's assignment. This is described in the Rationale section of boost::variant documentation: https://www.boost.org/doc/libs/1_69_0/doc/html/variant/design.html#variant.… In boost.variant, only these programs pay for the overhead that really invoke the assignment operator. Neither of the solutions seems strictly superior than the other. The double storage could be thought as better because it seems to be able to cover use cases where heap allocations are banned altogether. On the other hand, in these applications it is difficult to imagine that X and Y would be throwing exceptions in move constructors or during initialization. One inferiority of boost::variant is that it can fail for its own reasons unrelated to failures of X and Y. Even if no operations on X and Y throw during the assignment of variant, the variant can still throw because it allocates memory. Some people believe that an application cannot recover from bad_alloc anyway, but this is not a universally held view. To me, the important question is, do we really need the never-empty guarantee. It was an unquestionable requirement for the initial design of boost::variant. Now, variant2 is advertised as an allegedly superior solution to std::variant, because the latter does not provide the never-empty guarantee, even though the cost of providing it is significant. But I myself fail to see the *practical* value of the never-empty guarantee. The argument I hear is that, we want to make it an invariant that either X or Y is stored in variant. I agree with this goal in general, but the costs and contortions required to satisfy it outweigh the benefit. Now, I hear that if the invariant is weakened everyone will have to check everywhere if any variant is in a valueless_by_exception state. This seems to be confirmed by the semantics of std::variant::visit(), which requires that valueless_by_exception is checked and an exception thrown on valueless. This last part is indeed strange in std::variant, but I do not agree that the fix is to provide a never-empty guarantee at the cost of compromising run-time performance and complicating the design. I can think of the following alternative design. The invariant of a variant (pun intended) allows for a valueless_by_exception state. There is no way to get to this state other than by throwing form the initialization of Y in variant's assignment or .emplace() operation. Calling .visit() on a valueless variant is UB. The destructor and reset functions such as assignment and .emplace() can handle the valueless state. This is almost what std::variant does except for UB in .visit(). Why I find this superior to variant2. 1. It is simpler, faster and smaller. 2. Observing the valueless state can only happen when somebody is handling exceptions incorrectly. And in that case this is exception handling strategy that needs to be fixed: not the variant's guarantees. It should be noted that variant2 DOES NOT PROVIDE A STRONG EXCEPTION SAFETY GUARANTEE. The never-empty guarantee has a certain negative effect of confusing people so that they are led to believe that they have strong exception safety. But they don't. even expert programmers in this forum expressed their surprise that changing from X to Y in variant<X, Y, Z> can get them a variant storing Z. Sometimes it is even trickier: X may be a container that currently stores 10 elements. You assign Y, and after the exception you get an X that stores zero elements. Because of these problems, the only reasonable thing to do is to follow the advice from Dave Abraham's article: https://www.boost.org/community/exception_safety.html To quote the relevant part, "If a component has many valid states, after an exception we have no idea what state the component is in; only that the state is valid. The options for recovery in this case are limited: either destruction or resetting the component to some known state before further use." If this principle is followed no-one will ever observe the valueless_by_exception state. This also applies to variant2. If this principle from Dave Abrahams is followed, no-one will ever benefit from the never-empty guarantee (but people will still pay the costs of providing it). You cannot do anything meaningful with variant that threw other than destroy or reset it. (But it is probably best to destroy it.) If objects are allowed to survive the stack unwinding, they should either offer a strong exception safety guarantee, or you have to have some very detailed knowledge of a given particular type how its state gets modified under exceptions, but this is usually very difficult and best left to experts. I have started a thread in this list a while ago, requesting for an example of code that *correctly handles exceptions* (does not stop stack unwinding at random places), where the programmer would make use of the never-empty guarantee , and chose something else than destroying or resetting the variant. And although I received some generic statements, referring to the purity of the design, strength of the invariants, and the easiness of thinking or "correctness", none of the proponents of the never-empty guarantee gave such an example. Which might be an indication that the problem we are solving may be nonexistent. I am not sure of this claim, but I have not seen any convincing example either. I believe that we are facing one of this problems where the strong invariants of the type need to be weakened due to practical considerations. I can see no correctness issues with valueless state other than in programs that are already exception-unsafe. Also, I have heard claims that if someone is fine with valueless state they should put std::monostate as one of the types and the same effect without double buffering is achieved. But this is not true. Variant with monostate can get the degenerate state in a correct program; often: in the variant constructor. Now I really have to special-case it whenever I inspect the variant object, which is a nightmare: this is really a weak invariant in an allegedly strong-invariant variant. In contrast, for std::variant you only get the valueless state in the program that incorrectly handles exceptions: no need to special-case the valueless_state when doing visitation.. variant2 is not a replacement for std::variant, as the choice to support never-empty guarantee at the cost of more expensive operations and increased object size is not necessarily superior. Even if my view is not generally held, it has to be acknowledged that the issue is controversial. Variant2 cannot replace boost::variant either. This is not only about supporting pre c++11, but also for different trade-offs in never-empty guarantee, which were deemed inferior in boost::variant design. variant2 is ismply a third point in the multi-dimensional design space of different trade offs for variant-like libraries. On a different subject, one thing that is missing from both: boost::variant, and std::variant, is the narrow-contract observers for the specific stored type, useful when I know by other means what is currently stored in the variant object. This is something the third variant implementation has a chance to change, however it chose to follow its predecessors. This seems somewhat counter to the spirit of C++. We requested a similar thing of Niall's Outcome library, and the narrow-contract observers were added. Below is the comparison between boost::variant, std::variant and variant2. I do not know how to make a table in the email discussion interface, so I will have to make it with a list. 1. Works in pre-c++11 dialects * boost::variant: yes * std::variant: no * variant2: no 2. Size of variant<X, Y> (when X and Y are unfriendly) * boost::variant: sizeof(void*) + SXY (SXY is the size of union{X x; Y y;}) * boost::variant: sizeof(int) + SXY * variant2::variant: sizeof(int) + 2 * SXY 3. Uses heap allocations * boost::variant: yes * std::variant: no * variant2: no 4. Throws its own exceptions in assignment * boost::variant: yes * std::variant: no * variant2: no 5. Fast (narrow contract) access to X alternative. * boost::variant: no * std::variant: no * variant2: no 7. Strong exception-safety guarantee * boost::variant: no * std::variant: no * variant2: no 8. Never-empty guarantee * boost::variant: yes * std::variant: no * variant2: yes 9. Throws its own exceptions in visitation * boost::variant: no * std::variant: yes * variant2: no Regards, &rzej;

5 19

[variant2] Andrzej's review -- design
by Mike 04 Apr '19

04 Apr '19

> Every time you touch a variant object, you must consider the possibility of it being valueless.Â No I don't. It just works and I explained why. Could you please point out specifically where I made a mistake in my reasoning in the mail before where I discussed the behavior of all member functions? And again: I'm not arguing that one is better than the other. I'm saying it doesn't matter, but I'd much perfer a design that is in line with std::variant instead of having yet another slightly incompatible version of variant that doesn't offer any significant benefit (would be a different story if it would always offer the strong exception guarantee).

2 1

Regarding Boost.Astronomy GSoC19
by sarthak2007 04 Apr '19

04 Apr '19

Hello, For the competency test I had used quantity<length> of boost::units in place of double to store the values of coordinates with their units. But in project we have to deal with boost::geometry. One way it can be done is that whenever we use functions for dot product, cross product, etc. directly from boost::geometry then we just pass the values of coordinates in them instead of units. There will be no problem considering units in calculations as boost::units convert the values stored into SI units so all the calculations will be involving coordinates with SI units. But then we will have to change the way of storage of coordinates as boost::geometry can't be used to store coordinates(with units) as it does not support units. Is it the right approach or there is some nicer way to implement this? Thank you, Sarthak Singhal -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

2 1

[gsoc 19]proposal to project 1 Boost.GIL
by raghuchandra kanakamedala 04 Apr '19

04 Apr '19

Hi my proposal link: https://docs.google.com/document/d/1-BZO0VuIcebe1ZcdyxHGjOEkQL3eeaXwGtKCWyQ… .Please suggest me any changes if required. Thanking you K RaghuChandra

2 2

variant - off topic
by Robert Ramey 04 Apr '19

04 Apr '19

I've been and observer on the discussions regarding variant, expected, outcome, optional, outcome and ?? for sometime. I'm pretty amazed at the amount of controversy each and everyone of these in every forum - here, C++ committee, etc. I'm beginning to wonder this isn't telling us something. It seems natural that when making a new C++ data type, we should want to implement the assignment operator. Why - well every variable needs to be assigned to from time to time. Why is this so? Well ... Suppose we break this assumption and consider the idea that assignment doesn't make sense for every type. A variant is a "meta-type" or "sum type" which "holds" one of a set of other types. Such a variant can take on the character of any one of type types it is holding. When does it make conceptual sense for a variable to change it's type one it has been initially assigned. I've been trying to think of one and haven't been successful. Here are a few of the scenarios I've considered. a) Returning a sum type - the most common scenario for a variant. Doesn't require a assignment. Copy/move may still be required of course. b) looping through a vector of variants as in vector variant<...> v; for( variant<...> v : [](){...} fix with change to vector variant<...> v; for( variant<...> & v : [](){...} c) set according to condition variant<...> r; if(i < 0) r = v<t1>(...) else r = v<t2>(...) fix with change to variant <...> r = (i < 0) ? v<t1>(...) : v<t2>(...); d) insert your own use case here. That is, look at your own usages of assignment to these types and see if there is not an easy way to re-factor your code to avoid assignment. I'll concede that, influenced by functional programming style, with a little experimentation with F# and propaganda from the Haskell community, I've become accustomed to code in the above way. Also I've become afraid to assign anything to these types. The discussion has made me aware of a raft of unintended consequences of doing what on it's surface seems a trivial operation. I've gotten to the point that assignment to a variant type, or "changing the type" of a value at runtime is not code smell to me. Maybe all this could be just eliminated if this became the accepted position. Of course I realize that by engaging in the practice I do, the whole issue becomes irrelevant to me personally. And I can always create variant types as "const". It's not about that. It's about avoiding the creating of vocabulary types which lead to problems. So - simple proposal. Require that sum types have operator= deleted. Robert Ramey

3 5

[variant2] never-empty guarantee, again
by Andrzej Krzemienski 04 Apr '19

04 Apr '19

wt., 2 kwi 2019 o 22:59 Peter Dimov via Boost <boost(a)lists.boost.org> napisał(a): > Andrzej Krzemienski wrote: > > > Can you show a destructor like that, does a visitatoin on a variant, and > > that you wouldn't be ashamed to put in your program? > > The destructor doesn't have to do visitation. It merely needs to call a > function f1, which calls a function f2, which calls a function f3, which > calls a function f4, which does visitation. > > What we've been telling you from the start is that this forces you to > partition your functions into two classes, one allowed to do visitation, > the > other not, then keep track of which is which, never calling the wrong > class > in a destructor, or from a catch clause. > The fact that I have to partition all functions into two categories isn't new or surprising. When defining an operation that needs to provide a strong exception-safety guarantee I need to some use operations that offer no-fail guarantee. So I need to be aware which operations offer no-fail guarantee and use only those. I do the partitioning, and I need to be cautious. When I define the destructor, again I do not have the liberty to use any function I can use in other parts of the code. In destructor I can only use functions that do not signal failure through exceptions if they fail. And not signalling failures is ugly on its own, so I am inclined to also just use functions that cannot fail. I have to do the partitioning again. When I try to go back and recall how the destructors I write look like, they fall into three categories: 1. Some types just aggregate other types. The implicitly defined destructor only calls the destructors of subobjects. 2. Sometimes I need to provide a RAII interface for a system resource or a C component. In that case my implementation uses only ints and pointers and system calls. When defining the destructor, I have confidence that there are no unexpected types hidden by templates, or functions with unexpected types with unpredictable guarantees. 3. When I define a generic component, such as optional<T>, in my destructors the only operation on the unknown type T is to call its destructor. Other operations in the destructor are performed on concrete types with no-fail guarantee such as `bool`. The situation is no different for std containters: for T, they only call destructors, other operations are on concrete types: pointers, memory deallocation. No way a variant or other unexpected type could get there, even indirectly. I know people are using destructors for other things, like committing the DB transaction, but this is what I call bad exception handling. Such implementations are usually incorrect: either you do not report failures in such case, or you are reporting failures when there is none. Your example of a destructor, to me, also falls into this category: template<class T> class monitor > { > char const* file_; > int line_; > T const& v_; > T old_; > > public: > explicit monitor( char const* file, int line, T const& v ): > file_( file ), line_( line ), v_( v ), old_( v ) {} > > ~monitor() > { > if( v_ != old_ ) { > std::clog << file_ << ":" << line_ > << ": monitored value changed from " > << old_ << " to " << v_ << std::endl; > } > } > }; It calls operations on an unknown T that could fail and throw: comparison, streaming. Streams themselves could throw. Such implementation has other problems before we even consider a variant. And, of course, this has nothing to do with visitation, specifically. The > exception safety guarantee is a global thing. Once you lose basic, you lose > it everywhere, not just for visit. > Why are you mentioning "basic" (guarantee) here? In the vision that I propose variant offers basic guarantee. It is just that the invariant is weaker. This is analogous to a (potentially smart) pointer: normally you can call `*p`, but sometimes (on nullptr) it is UB, so you may need to check what state it is in. Regards, &rzej;

2 2

Boost commercial support policy
by SOCIPROJECT 04 Apr '19

04 Apr '19

Hi,Good day.  This is Shuvransu Banerjee, development manager at Ushamartin Technologies. We build software products on Telecom Billing.We are at the planning level and thinking about using Boost in our legacy code. We have the following queries: Can we use Boost commercially? Is there any support available? If yes, then please let us know the various options for support.Thanks & Regards,Shuvransu Banerjee

2 1

B2, transition to C++
by Rene Rivera 04 Apr '19

04 Apr '19

After six months of, slowly, working towards this I can now say that the C++ compiled version of the B2 engine is ready for use. As such I plan, if there are no objections from Steven Watanabe and Vladimir Prus, to merge the result into the develop branch shortly after the 1.70 release. The history note accompanying this "new" engine version goes like this: === Version 4.0.0 After even more years of development the landscape of build systems has changed considerably, and so has the landscape of compilers. This version marks the start of B2 transitioning to a C++ implementation. Initially this means that the engine will be compiled as C++ source but that source is still the base C implementation. Over time it will transform to a C++ code base in both the engine and build system. Some changes in this start: * Requires C++ 11 to build engine. * Simplified build scripts to make it easier to maintain. * Building with C++ optimizations gives an immediate performance improvement. === There will obviously be bumps on the road when that merge goes in. As the C++ 11 requirement might require some changes for testers and users. But hopefully they will be minor. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

2 1

Re: [boost] [variant2] Review of Variant2 started today : April 1 - April 10
by Peter Dimov 03 Apr '19

03 Apr '19

> Andrey Semashev wrote: > > Also, IMHO, it's better to have libraries more focused and fine grained. > > Why not have `expected` as a separate library? > > expected<T, E...> is basically a variant, with a slightly different > interface. To expand on that a bit... to implement expected<T, E...> you need an underlying variant. You can either implement your own ad-hoc one, which is a duplication of work; or you could use an existing variant, but then you inherit its properties and have to reflect those in the specification of `expected`. For instance, if the variant can be valueless, you need to figure out what to do in `expected` when it gets into that state. For those reasons, it makes most sense to develop `variant` and `expected` in parallel, as parts of the same library.

4 4

Master branch for 1.70.0 closes today!
by Marshall Clow 03 Apr '19

03 Apr '19

We're still in the post-beta phase, so please refer to < https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> -- Marshall

2 2

[gsoc19] Interested in Boost.Geometry PROJECT 2 (Support for non-cartesian)
by rika 03 Apr '19

03 Apr '19

Hi! I'm Rika from Japan, currently in 4th grade in the University of Tokyo. I'm going to take part in GSoC 2019, and interested in Boost.Geometry PROJECT2 - "Implement support for non-cartesin geometries in convex_hull()" I've already done a competency test, and writing a project proposal. [Competency test] https://github.com/rika77/boost I'm seeking for a mentor for this project. I also have 1 technical question & 1 general: 1. I'm afraid to ask, but what algorithm is currently used in convex_hull()? I read algorithms/convex_hull.hpp carefully, but I couldn't find out. 2. On GSoC GitHub page, there are 4 projects on Boost.Geometry, but are only 2 potential mentors. I guess that only 2 students are chosen, right? I just want to make sure. Thanks, Rika -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

4 3

Master branch open for merging
by Marshall Clow 03 Apr '19

03 Apr '19

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See < https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> -- The Boost Release Team

11 48

[gsoc19] late application for Boost.SafeFloat
by Thomas Ferrand 03 Apr '19

03 Apr '19

Hello, I am a student and I am interested in taking part of GSoC this summer. But I am a little late as the application are due to next week so I was wondering if I could still take part. The project I am interested in is Boost.SafeFloat, mentored by Damian Vicino. As for the competency test, it has already been taken care of as I believe it is the same that last year and I completed it then https://github.com/aTom3333/boost_competency_test/ Thomas Ferrand

4 4

Boost.Python
by Siddhartha Sen 02 Apr '19

02 Apr '19

Boost.Python does not have any added projects as of yet. I have completed my competency test and have a couple of ideas of my own.Need a potential mentor to discuss them with and review my proposal. Thanks.

2 1

[gsoc19] looking for mentor
by Aziz Mousa 02 Apr '19

02 Apr '19

hi, I have my idea to contribute in boost project, I read the boost libraries list and see that the author of Algorithm is "Marshall Clow" I want to know how to contact with him to tell him about my idea. thanks.

1 0

[gsoc][gsoc19] Communication between students and mentors
by Mateusz Loskot 02 Apr '19

02 Apr '19

Hi, Are there any guidelines related to communication between students and mentors during GSoC? Many participating organisations and projects do explicitly recommend that student/mentor communication is conducted via public channels. e.g. https://docs.moodle.org/dev/GSOC """ Note: With regards to the communication culture in the Moodle project: We always prefer transparent communication in public forums and tracker comments over private messages and emails. Please respect this and avoid contacting GSOC admins and mentors directly unless you really need to talk about something sensitive or personal. """ or at least regular/weekly reports to dedicated and project-specific list https://wiki.osgeo.org/wiki/Google_Summer_of_Code_Recommendations_for_Stude… Would it be possible to ask for similar transparent mode during Boost GSoC? I do realise one challenge is that Boost mailing list traffic could increase a lot, too much for some subscribers. Perhaps a solution to that could be setting up dedicated lists: gsoc(a)lists.boost.org or even <library>@lists.boost.org Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

2 2

(no subject)
by Aziz Mousa 02 Apr '19

02 Apr '19

hi, I submit my proposal draft on GSoC and I want to know how to meet a mentor to see my proposal.

3 2

[gsoc19] Seeking a mentor for Boost.GIL project
by Igor Antropov 02 Apr '19

02 Apr '19

DearSir/Madam, My name isIgor Antropov and I would like to participate in GSoC 2019.I amfirst-year undergraduate master majoring in Software Engineering at ITMOUniversity (Saint Petersburg National Research University of Information Technologies,Mechanics and Optics).I aminterested in computer vision and C++. I have made AR-application using Unityand OpenCVForUnity at my third-year of bachelor degree. Unfortunately, thatOpenCVForUnity was based on OpenCV version 2.1 or smaller and was the only onefree to use. There was no algorithm for markers detection, so I had to codeit. At the fourth-year, I have implementobject tracking algorithm with C++ and OpenCV using HOG features and colornames features. Additionally, I havebeen working as programmer with Qt for 1 year. I aminterested in implementation of different algorithms using GIL, so I propose toimplement some image feature detection and matching algorithms. For example,ORB keypoints detector(http://www.willowgarage.com/sites/default/files/orb_final.pdf) and brute-forcematching. Besides, I think Boost.GIL numeric algorithms can have some improvements (add 2D convolution, add convolve_option_extend_reflect as convolve_boundary_options). If Boost.GIL users need some other algorithms to be implemented,please contact me. As my competencytest, I have implement a simple Canny edge detection algorithm using GIL. https://github.com/boostorg/gil/pull/258 Sincerely, IgorAntropov

2 1

[GSOD] Looking for mentors and projects
by Damian Vicino 02 Apr '19

02 Apr '19

Hi, I'm starting preparing the application for Google Season of Docs 2019. I created a wiki page to start collecting project ideas here: https://github.com/boostorg/boost/wiki/Google-Season-of-Docs-2019 Instruction of how to write a project idea are here: https://developers.google.com/season-of-docs/docs/project-ideas Please add any idea you have, even if you are not able to mentor it, someone else may volunteer for it. Best regards, Damian Vicino

4 4

[gsoc19] Seeking a mentor for Boost.Geometry project related to triangulation and random sampling
by Tinko Bartels 01 Apr '19

01 Apr '19

Hi, I am interested in participating in this year's Google Summer of Code with a contribution to Boost.Geometry. I am looking for mentors and I understand that potential mentors for Boost.Geometry-related projects are Vissarion Fysikopoulos and Adam Wulkiewicz. My proposal is a project that is based on project 3 and 4 for Boost.Geometry in the Wiki. I propose to add concepts for triangles, triangulation, and point-generators for random sampling, as well as corresponding models and an algorithm for Delaunay-triangulation with parametrizable geometric predicates. The first draft of my proposal can be found here: https://docs.google.com/document/d/17M44Hpn0KMuECztCbkvTYIeN2EiXbMAUsVni22K… My implementation of the tasks in the competency tests can be found here: https://tinko92.github.io/boost_geometry_GSoC_2019_project_3_4_test/ I'd be thankful for any feedback. Kind regards, Tinko Bartels -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

3 10

[gsoc 2019]proposal to Boost.GIL project 1
by raghuchandra kanakamedala 01 Apr '19

01 Apr '19

Hi Please give me your feedback on my proposal to increase my chases of participation in the project. link: https://docs.google.com/document/d/1-BZO0VuIcebe1ZcdyxHGjOEkQL3eeaXwGtKCWyQ… Thank you K RaghuChandra

1 0

[GSOC 19]Boost.GIL
by raghuchandra kanakamedala 01 Apr '19

01 Apr '19

Hi Is there a mentor for Boost.GIL.If so please send me his/her email id. Thanking you K RaghuChandra

1 0

[format] Allow the format library to use std::optional
by Sean Farrow 30 Mar '19

30 Mar '19

Hi, Would be possible/desired to allow boost.format to use std::optional instead of boost.optional when compiling a C++17 project. I've raised a GitHub issue to resolve this: https://github.com/boostorg/format/issues/63 I would be happy to do this if it were warranted. Kind regards Sean.

1 0

Re: [boost] [Boost-build] Building Boost 1.69 with Visual Studio 1.69
by Steven Watanabe 29 Mar '19

29 Mar '19

AMDG On 3/27/19 12:02 PM, Paul Bristow wrote: >> <snip> > I was fully up-to-date on develop yesterday, and installed git a week ago (new machine ;-) ). > The current revision of Boost.Build in develop should be e22a75c8 (March 18) > I am also slightly concerned that specifying the cl.exe fully may not be updated when Visual studio is updated, as happens today? > But it does seem to using the new compiler version, even though the full cl.exe file specification is no longer correct. > Similarly vsvarsall.bat location in the set command will change. > > But I am getting Boost library files built OK for several compilers and versions, so that's progress. > Hmm. It looks like VS2019 isn't being autodetected. It seems to be working for Tom's test runners. Maybe see what you get from: vswhere -latest -products * -requires Microsoft.VisualStudio.Component.VC.Tools.x86.x64 -property installationPath -version "[16.0,17.0)" (This is how Boost.Build tries to detect VS2019.) In Christ, Steven Watanabe

6 12

Regarding BOOST.Astronomy
by Sarthak Singhal 29 Mar '19

29 Mar '19

Hello everyone, I am not able to understand what exactly is to be done to complete the parser for FITS and I have also tried understanding the codebase but I am not getting what is the work done till now. Can you also provide some resources? Thanking you Sarthak Singhal

4 3

[visibility][test][osx] visibility warnings with 1.70beta
by Raffi Enficiaud 28 Mar '19

28 Mar '19

Hi, I have a side project that requires boost.test and I thought it is the right time to use the beta build of 1.70. At link time for my project (in this case a simple boost.test module), I have tons of warnings like the following: ld: warning: direct access in function 'boost::unit_test::decorator::depends_on::apply(boost::unit_test::test_unit&)' from file '/Users/raffi/from-big-laptop/code/software_workshop/sw_thirdparties/osx/boost_1_70_0_b1/lib/libboost_unit_test_framework-xgcc42-mt-x64-1_70.a(decorator.o)' to global weak symbol 'boost::unit_test::basic_cstring<char const>::null_str()::null' from file '/Users/raffi/code/mpi/mpi_kmeans/build/MPI-Kmeans.build/Debug/test_mpi_kmeans.build/Objects-normal/x86_64/test_cls_and_func_impl.o' means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings. running Xcode 10.1 on 10.14/mojave. I am building boost like this: ./b2 \ cflags="-mmacosx-version-min=10.10" \ cxxflags="-std=c++11 -stdlib=libc++ -mmacosx-version-min=10.10" \ mflags="-mmacosx-version-min=10.10" \ mmflags="-mmacosx-version-min=10.10" \ linkflags="-stdlib=libc++ -mmacosx-version-min=10.10" \ --prefix=`pwd`/../${build_folder} \ --without-log \ --layout=versioned \ install Each of the files that are being built in my project and that are raising the warning have a compilation command like this: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++ -DBOOST_ALL_NO_LIB -DKMEANS_VERBOSE=0 -I/Users/raffi/code/mpi/mpi_kmeans/include -I/Users/raffi/code/mpi/mpi_kmeans/applications/include -isystem /Users/raffi/from-big-laptop/code/software_workshop/sw_thirdparties/osx/boost_1_70_0_b1/include/boost-1_70 -O3 -DNDEBUG -std=gnu++11 -o CMakeFiles/test_mpi_kmeans.dir/test/test_kmeans.cpp.o -c /Users/raffi/code/mpi/mpi_kmeans/test/test_kmeans.cpp which is pretty much what I had so far and before 1.70. Boost.test is using BOOST_SYMBOL_VISIBLE to make a symbol public, including the static build variant. Why does the linker say """ This was likely caused by different translation units being compiled with different visibility settings. """ is completely unclear to me. How can I inspect what b2 emits as compilation command line for further debugging? All those visibility issues are causing me a lot of headache :) Thanks! Raffi

3 5

Gsod19 interest
by Damian Vicino 27 Mar '19

27 Mar '19

I'm wondering if there is interest to make boost participate in the Google season of docs. The program is similar to Google summer of code in many ways, but the outcome is production of documentation. It Details: g.co/seasonofdocs <https://developers.google.com/season-of-docs/>

5 15

[GSOC 2019]
by shehab alaa 27 Mar '19

27 Mar '19

Hi, I’m student willing to participate in GSOC 2019. I have finished my competency test for Boost.uBLAS and I have interest in projects 2 (Adding new numerical linear and multilinear algebra algorithms).So I’m writing looking for mentor who have interest to guide me. And here is my GitHub link for competency test https://github.com/Shehabalaa/CompetencyTest Best regards, Shehab Alaa

2 1

Re: [boost] [review][variant2] Variant2 Review Starts April 1
by dariomt＠gmail.com 26 Mar '19

26 Mar '19

> > The class boost::variant2::variant<T...> is an almost conforming > implementation of std::variant with the following differences: > I see the useful comparison to std::variant in the doc, however I'm using boost::variant extensively in my code. It would be very useful to have also a short comparison to boost::variant in the doc, as I would expect many more current users of the venerable boost::variant than of its much younger cousin std::variant. Thanks!

6 8

Building Boost 1.69 with Visual Studio 1.69
by Trueman, Chris 26 Mar '19

26 Mar '19

Maybe I'm getting ahead of myself given the recent topic about picking a version number for the latest MSVC toolset but I'm having trouble building boost 1.69 with Visual Studio 2019 preview. I blindly assumed the toolset was 14.20 (given the directory where cl.exe is found). Letting b2 determine the version yields vc141 in the lib names. Trying to force 142 with: using msvc : 14.2 : <path to cl.exe> ; in project-config.jam yields errors about unescaped characters. Suggestions welcomed. Chris. INTELLICORP LEGAL NOTICE: This E-Mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying or other use of this message or its attachments is strictly prohibited. If you received this message in error, please notify the sender immediately by replying to this message, and then delete it.

6 11

[fibers] Great amount of errors and warnings raising out of valgrind
by Stephan Menzel 26 Mar '19

26 Mar '19

Hello all, I was just in the process of doing vagrind runs on a server process that recently switched to an architecture using boost fibers. Specifically buffered_channel as a number of worker fibers run in a thread. The process was regularily checked with valgrind before but now I'm getting overwhelmed by the amount of messages. Uninitialized values, invalid writes and reads all across the board and all seem to come out of fibers. I see no direct mention of my code. A few samples: ==8024== Thread 1: ==8024== Conditional jump or move depends on uninitialised value(s) ==8024== at 0x454F98: unique (circular_list_algorithms.hpp:112) ==8024== by 0x454F98: empty (list.hpp:540) ==8024== by 0x454F98: boost::fibers::buffered_channel<std::function<void ()> >::close() (buffered_channel.hp ==8024== by 0x454FDB: boost::fibers::buffered_channel<std::function<void ()> >::~buffered_channel() (buffere ==8024== by 0x4376BF: operator() (unique_ptr.h:78) ==8024== Invalid read of size 8 ==8024== at 0x9C1756: boost::fibers::context::~context() (in /my_server) ==8024== by 0x9C31CF: boost::fibers::main_context::~main_context() (in /my_server) ==8024== by 0x6B0B85E: __call_tls_dtors (in /usr/lib64/libc-2.26.so) ==8024== by 0x5D49558: start_thread (in /usr/lib64/libpthread-2.26.so) ==8024== by 0x6BC92FE: clone (in /usr/lib64/libc-2.26.so) ==8024== Address 0xa6f0010 is 32 bytes inside a block of size 232 alloc'd ==8024== at 0x4C2D1DA: operator new(unsigned long) (vg_replace_malloc.c:334) and thousands more similar to this. Now, is there something about fibers that causes this as false positives (such as valgrind not knowing about fibers or coroutines) or is there an underlying problem here? This is running on AWS Linux 2, built with gcc 7.3, boost 1.69. Multithreaded release build with debug info. Nothing out of the ordinary. I am a bit concerned about this and wanted to let the list know. Can provide more output on demand. Cheers, Stephan

2 2

Re: [boost] [review][variant2] Variant2 Review Starts April 1
by dariomt＠gmail.com 26 Mar '19

26 Mar '19

> > On Mon, 25 Mar 2019 at 17:18, dariomt--- via Boost <boost(a)lists.boost.org> > wrote: > > > ... as I would expect many more current users of the venerable > > boost::variant than of its much younger cousin std::variant. > > > > Why do you expect that and do you think that will stay that way? Well, Boost.Variant has been around so much more time than std::variant, so this seems obvious to me. For new code, maybe people will just use std::variant, but there's more old code than new code. Also, I'd say the cost of migrating from Boost.Variant to std::variant is non-zero, and the benefits are not clear (to me), so I'd expect not many people to undergo this migration. My feeling is that the library is aimed at current users of std::variant, offering a "better" pin-compatible alternative, but if I'm using Boost.Variant I believe I also should be considered a potential user. That's why I'm curious about the Boost.Variant2 review, we might get more clarity by comparing the three versions, and we may even get guidance for a migration path from Boost.Variant to Boost.Variant2. > My > personal feeling is that C++17-use is picking up at break-neck speed. For > good or for worse, although there appears to be a lot of controversy over a > (any) variant [and there are quite some quite different implementations > around], the std::variant is the one in the std, which seems to give it a > head start. Well, in my (limited) experience Boost is ubiquitous, so being in std is not that much of a head start. > In my view there can only be one objective with boost varant2, > and that is if it is decided [here] that it is (much) better than the > current std::variant, the C++20 std::variant should be/become the proposed > boost::variant2. > > degski > I wonder if code dealing explicitly with valueless_by_exception() will break if you make this change.

2 1

Re: [boost] [review][variant2] Variant2 Review Starts April 1
by dariomt＠gmail.com 26 Mar '19

26 Mar '19

> > dariomt--- wrote: > > > The class boost::variant2::variant<T...> is an almost conforming > > > implementation of std::variant with the following differences: > > > > > > I see the useful comparison to std::variant in the doc, however I'm > using > > boost::variant extensively in my code. > > > > It would be very useful to have also a short comparison to > boost::variant > > in the doc, as I would expect many more current users of the venerable > > boost::variant than of its much younger cousin std::variant. > > The main difference is that Variant2 is a pin-compatible replacement for > std::variant, whereas Boost.Variant isn't (at least for now). So it's > easier > to switch from std::variant to Variant2 and back (depending f.ex. on > whether > std::variant is available.) > > The second most important difference would probably be the fact that > Boost.Variant may do heap allocations. > This is useful info, thanks! I understand that the main objective is to offer a "better" std::variant, but as a user of Boost.Variant wondering "Should I consider migrating to Boost.Variant2?", I would expect a section in the doc addressing this question.

1 0

Which forum to handle issues/questions regarding libraries
by Robert Ramey 25 Mar '19

25 Mar '19

I've been studying the boost multiprecision library and I have a few questions relating to various aspects of said library. These questions are quite specific to that library and I'm not sure that they are of wider interest other than to a couple people. So I'm wondering if it would be better to post these as library issues on github or on this list or both. It used to be simple but now we have at least three places to discuss these things: slack, here and github issues for the library in question. Also sometimes some PRs can highlight differences which can get ironed out in the PR comments. Do we have a consensus as to the preferred way to select the correct forum? Robert Ramey

5 4

Looking for a Mentor: GSoC 19: Boost.uBLAS: Linear and Multilinear...: Project 1 and 2
by forcha glen 24 Mar '19

24 Mar '19

Hello, I am interested in any of these two projects. I do not yet have a mentor. I need mentor. Regards, Glen

2 1

Re: [boost] Master branch open for merging
by Nikita Kniazev 22 Mar '19

22 Mar '19

I would like to merge Spirit to master. The develop contains bunch of minor changes, but I important ones are: Endian namespace pollution and macros conflict fixes: https://github.com/boostorg/spirit/commit/6c258d506c2bbadccdb9f25e481984aca… https://github.com/boostorg/spirit/commit/74c0ec310a2345cb95ffb947327f69007… https://github.com/boostorg/spirit/commit/9d48b5a23197bbbcc4a3a8990c164b1cf… GCC 6/7 regression avoidance: https://github.com/boostorg/spirit/commit/8bd9b6ece40f9324a902bb0f726e785ff… The regression matrix is green for two weeks.

2 1

[release] Boost 1.70.0 Beta 1 is now available
by Marshall Clow 22 Mar '19

22 Mar '19

[ resending with a non-empty subject line ] Boost release 1.70.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.70.0.beta1/source/> The SHA256 checksums are as follows: dbf89645e509acb2e53eac3c633834f1dec80bd8622e6e652a9741dcf0807f17 ./boost_1_70_0_b1.7z 957b984b58656a3ec00661ecad7ef82e3a094bad36e37b9e6624843237854679 ./boost_1_70_0_b1.tar.bz2 76d149c1fb9e8a5ceb3bc1e5587edc40fa79a43e8b990d877c2210f0382b9421 ./boost_1_70_0_b1.tar.gz 71e990b2c26880521fd98459b184ee172ce1c46dcf554b6eaab7776b8b6369a6 ./boost_1_70_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_70_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

6 14

[Process] Proposed solution for posix pipes staying open
by Bills, Jason M 22 Mar '19

22 Mar '19

Hello, I'm new to Boost and looking for some help on the right process to propose patches. I'm running in an embedded Linux environment (OpenBMC) using Boost 1.69.0 and just switched a couple of std::system() calls to boost::process::system() calls. After making this change, I noticed that each time my process executed the bp::system() call, I would get an extra pipe fd in my /proc/<pid>/fd list. I did some debugging and have found a possible solution for this issue in the Boost.Process posix headers that I would like to propose. What is the right forum or process to post my patch (post it here, github pull request, etc.)? Thanks! -Jason

2 2

questions about boost multiprecision
by Robert Ramey 22 Mar '19

22 Mar '19

I'm looking more carefully at Boost Multiprecision than I have in the past and have a couple of questions: It's not clear to me how errors are handled. For example, what happens in a divide by zero? Or what happens when a result overflows. I'm aware that this will likely vary depending on whether the arguments are arbitrary precision made a runtime or a precision fixed at compile time. In any case, looking through the manual I can't find this information. Of course this package is so ambitious, that it's possible that I've missed it but in that case a pointer would be appreciated. Spending some time on this makes me appreciate what an incredibly ambitious accomplishment this is. It's really unbelievable. I would be curious how frequently various parts of the package are used. Robert Ramey

4 4

usage of auto in tutorials
by Stephan Menzel 22 Mar '19

22 Mar '19

Hello all, I was eagerly awaiting the release of the 1.70 beta, especially for outcome, which I have much use for, having lots of async functionality. While looking at the tutorial here that https://www.boost.org/doc/libs/1_70_0_beta1/libs/outcome/doc/html/index.html I notice that auto is used instead of the types. Is there a background to this? I question if this is such a good thing in tutorials. The first thing I like to know about a new lib is the types and classes it offers and auto obfuscates this. Is there any consensus in the boost community as to how and if tutorials and docs should use auto? I have concerns about this and feel it doesn't increase the otherwise great quality of documentation and tutorials for new libs. Cheers, Stephan

10 17

[test] unit test command-line handling
by Stefan Seefeld 22 Mar '19

22 Mar '19

Hello, this is a question concerning the Boost.Test framework. I'd like to pass command-line arguments to my tests, and I'm unsure of how to proceed. I have found https://www.boost.org/doc/libs/1_68_0/libs/test/doc/html/boost_test/adv_sce…, which shows how to access the command-line programmatically, but that's declared obsolete, and it's also lacking some important info, such as how I should handle the argv vector. Are there any examples that demonstrate this use case ? Specifically: * What (non-deprecated) API can I use to access command-line arguments during test initialization ? * How does my own handling of command-line arguments interact with Boost.Test's own command-line argument handling ? Thanks, Stefan -- ...ich hab' noch einen Koffer in Berlin...

3 8

[move] Bug causing issue #81 in Interprocess
by Ion Gaztañaga 21 Mar '19

21 Mar '19

Hi, Looks like a Boost.Move bug that is causing problems in Interprocess and potentially in other libraries like Container. The bug is present in the soon to be released Boost 1.70. The bug was reported by Nikita Kniazev for Interprocess: https://github.com/boostorg/interprocess/issues/81 I've committed a simple fix in the develop branch: https://github.com/boostorg/move/commit/756c964798ff1110406fab541b85267aefb… I hope the regression can cycle soon and release managers can approve the patch for Boost 1.70. Best, Ion

1 0

[GSoC 2019] Seeking guidance for Boost.uBlas (Project 4)
by livingstonegcs 21 Mar '19

21 Mar '19

Hello Boost community, I am GCS Living Stone, a Computer Science and Engineering undergraduate at National Institute of Science and Technology. I have fair amount of knowledge in Linear Algebra and skills in C++, Python programming. I have gone through Boost GSoC2019 proposal list. I found interest in Boost.uBlas Project 4: Non-negative matrix factorization implementation. I am seeking information regarding where to submit the competency test and how to begin with the project proposal as the project description has not mentioned any specific techniques. [Also I would like to bring to your notice that the Boost.Python project just mentions the project number but does not describe the projects.] Looking forward for the advice and guidance in the mentioned issue. Thanking you, GCS Living Stone -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

1 0

GSoC : Boost.Geometry: Generic Geometry Library
by Sarah Arrey 20 Mar '19

20 Mar '19

Dear Sir/Madame, My name is Sarah Arrey. I am a student in the University of Buea, Cameroon. I have written professional programs in C++. As a result of my Anglo-Saxon culture, and currently in the faculty of science, I have good knowledge in mathematics beyond that of the high school; my country is Bilingual (English and French). I am interested in applying for the following two projects: PROJECT 3: Implementation of Algorithms for Computing the Delaunay Triangulation PROJECT 4: Implementation of Algorithms for Random Point Generation I am willing to forward code for the Programming Competency Test, when applying. How do I get started? Regards, Sarah

3 2

GSoC 2019 - Boost.Geometry: Generic Geometry Library
by Indira Ngandi 20 Mar '19

20 Mar '19

Hello, I am Indira Ngandi, a Cameroonian (not an Indian). I am a student in the University of Buea, Cameroon. I have good knowledge in C/C++. I also have good knowledge in British Further Mathematics. I am interested in applying for the following two projects. I know that only one can be accorded to me. I would like to apply for two to improve my chances of having one. The projects are: PROJECT 1: Implementing Algorithms for the Concave Hull problem PROJECT 2: Implementing Support for Non-Cartesian Geometries in Convex_Hull How do I start? Regards, Indira

4 4

Regarding BOOST.Astronomy GSOC'19
by Sarthak Singhal 20 Mar '19

20 Mar '19

Hello everyone, I am Sarthak Singhal currently in my second year pursuing Computer Science and Engineering from IIT Kanpur. I have checked out the astronomy library of boost and the work done on it in previous year's GSOC. I am interested in making contributions to this library. I am proficient in C++ and have an experience of about one and a half years. But before that I want to complete the programming competency test and wanted to know that whether I have to implement the vector class from scratch or I have use the part of boost/astronomy/coordinate/cartesian_representation.hpp and some other header files.

2 1

GSoC Linear and Multilinear Algebra with Matrix and Tensor Computations
by forcha glen 19 Mar '19

19 Mar '19

Hello, I am Glen Beloa. I am a student in the University of Buea, Cameroon. I am studying for a Master's degree in Telecommunications and Networking. I understand that I can apply for two projects. I would like to apply for the projects: Project 1 : Extending and modifying boost::numeric::ublas::tensor Project 2 : Adding new numerical linear and multilinear algebra algorithms How do I get started? Regards, Glen

1 0

GSoC Linear and Multilinear Algebra with Matrix and Tensor Computations
by forcha pearl02 19 Mar '19

19 Mar '19

Hello, I am Pearl Fri. I am a student in the University of Buea, Cameroon. I am studying for a BEng degree in Computer Engineering. I would like to apply for the following two projects: Project 3 : Modifying (smart) expression templates Project 4: Implementing non-negative matrix factorization in uBlas How do I get started? Regards, Pearl

1 0

MSVC 2019 and 1.70 beta
by Olaf van der Spek 19 Mar '19

19 Mar '19

Hi, Is 2019 not properly supported yet? > Building Boost.Build engine > 'cl' is not recognized as an internal or external command, > operable program or batch file. > Failed to build Boost.Build engine. > Please consult bootstrap.log for further diagnostics. >From a dev prompt it doesn't appear to work either: ********************************************************************** ** Visual Studio 2019 Developer Command Prompt v16.0.0-pre.4.2 ** Copyright (c) 2019 Microsoft Corporation ********************************************************************** C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview>cd /vc C:\vc>cd boost_1_70_0 C:\vc\boost_1_70_0>bootstrap.bat Building Boost.Build engine Generating Boost.Build configuration in project-config.jam for msvc... Bootstrapping is done. To build, run: .\b2 To generate header files, run: .\b2 headers To adjust configuration, edit 'project-config.jam'. Further information: - Command line help: .\b2 --help - Getting started guide: http://boost.org/more/getting_started/windows.html - Boost.Build documentation: http://www.boost.org/build/ C:\vc\boost_1_70_0>b2 warning: Did not find command for MSVC toolset. If you have Visual Studio 2017 installed you will need to specify the full path to the command, set VS150COMNTOOLS for your installation, or build from the 'Visual Studio Command Prompt for VS 2017'. Performing configuration checks - default address-model : none - default architecture : none Building the Boost C++ Libraries. error: No best alternative for libs/context/build/asm_sources next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>elf <threading>multi <toolset>gcc not matched -- Olaf

7 13

I am interested to participate in BOOST GSOC2019 project
by raghuchandra kanakamedala 19 Mar '19

19 Mar '19

Hi I am Raghuchandra studying 3rd year B.Tech at IIIT Hyderabad. It would be great to contribute to Boost.GIL: generic image library.I have ideas for both the projects.I had this course Digital Image Processing also done a project "Road detection from satellite images" based on the paper attached.my implementation link to git https://github.com/savera2020/dip_project/ .I have good skills in C++ programming. so can you provide the mail id of mentor so that we can go more deeper about the project.please consider my request to contribute to project.without a doubt i will give my best. best regards Raghuchandra

2 1

GSoC 2019 preparation , BOOST.uBLAS project
by mo'men 18 Mar '19

18 Mar '19

Hi, I’m Moamen Ahmed , 4th year student at computer engineering department at Ain Shams university ,Cairo, Egypt. I have read the interesting project ideas , and I have found myself interested in BOOST.uBLAS project. Also, I have good experience in Linear Algebra , and C++ programming. I have developed c++ projects on my own and still do . I ‘m trying now to make the competency test. I 'd like to join BOOST.uBLAS project ,so kindly , help me through the process on how to enhance my opportunity to join this project . Best regards, Moamen Ahmed

2 1

Call for Submissions: International Conference on Information Society (i-Society 2019)
by International Conference on Information Society 18 Mar '19

18 Mar '19

If you are not able to see this mail, click http://r.confinfosoc.org/mk/mr/hHTtReTMggQeh5kiYnT0MxUABiXYJEhpmmVH7xlJw4VK… for Submissions: International Conference on Information Society (i-Society 2019) ********************************************************************************** International Conference on Information Society (i-Society 2019) 22-24 October, 2019 Venue: Royal Marine Hotel Dún Laoghaire, Co. Dublin, Ireland www.i-society.eu ********************************************************************************* The i-Society is a global knowledge-enriched collaborative effort that has its roots from both academia and industry. The conference covers a wide spectrum of topics that relate to information society, which includes technical and non-technical research areas. The mission of i-Society 2019 conference is to provide opportunities for collaboration of professionals and researchers to share existing and generate new knowledge in the field of information society. The conference encapsulates the concept of interdisciplinary science that studies the societal and technological dimensions of knowledge evolution in digital society. The i-Society bridges the gap between academia and industry with regards to research collaboration and awareness of current development in secure information management in the digital society. The topics in i-Society 2019 include but are not confined to the following areas: *New enabling technologies - Internet technologies - Internet of Things (IoT) - Wireless applications - Mobile Applications - Cloud and iCloud - Multimedia Applications - Protocols and Standards - Ubiquitous Computing - Virtual Reality - Human Computer Interaction - Geographic information systems - e-Manufacturing - Electronic Discovery (eDiscovery) - Software Applications - Disruptive Technology *Intelligent data management - Intelligent Agents - Intelligent Systems - Intelligent Organisations - Content Development - Data Mining - Data Management Software - e-Publishing and Digital Libraries - Information Search and Retrieval - Knowledge Management - e-Intelligence - Compliance and Recovery from Data Loss - Knowledge networks - Risk Mitigation - Cost Efficiency - Quality Assurance - Information Management - Support Litigation - Complex Investigations *Secure Technologies - Internet security - Web services and performance - Secure transactions - Cryptography - Payment systems - Secure Protocols - e-Privacy - e-Trust - e-Risk - Cyber Security Investigations and Defence - Cyber law - Forensics - Information assurance - Mobile social networks - Peer-to-peer social networks - Sensor networks and social sensing - Information Security Compliance *e-Learning - Collaborative Learning - Curriculum Content Design and Development - Delivery Systems and Environments - Educational Systems Design - e-Learning Organisational Issues - Evaluation and Assessment - Virtual Learning Environments and Issues - Web-based Learning Communities - e-Learning Tools - e-Education *e-Society - Global Trends - Social Inclusion - Intellectual Property Rights - Social Infonomics - Computer-Mediated Communication - Social and Organisational Aspects - Globalisation and developmental IT - Social Software - Smart City *e-Health - Data Security Issues - e-Health Policy and Practice - e-Healthcare Strategies and Provision - Medical Research Ethics - Patient Privacy and Confidentiality - e-Medicine *e-Governance - Democracy and the Citizen - e-Administration - Policy Issues - Virtual Communities *e-Business - Digital Economies - Knowledge economy - eProcurement - National and International Economies - e-Business Ontologies and Models - Digital Goods and Services - e-Commerce Application Fields - e-Commerce Economics - e-Commerce Services - Electronic Service Delivery - e-Marketing - Gig Economy - Online Auctions and Technologies - Virtual Organisations - Teleworking - Applied e-Business - Electronic Data Interchange (EDI) - Innovative Strategies - Business Intelligence - Information Intelligence - Forensic Accounting *e-Art - Legal Issues - Patents - Enabling technologies and tools *e-Science - Natural sciences in digital society - Biometrics - Bioinformatics - Collaborative research *Industrial developments - Trends in learning - Applied research - Cutting-edge technologies - Industrial Control Systems - Communications Compliance * Research in progress - Ongoing research from undergraduates, graduates/postgraduates and professionals SUBMISSION INSTRUCTIONS: * You can submit your extended abstract or paper online at http://www.i-society.eu/paper-submission/ or email it to papers(a)i-society.eu * You can submit your poster via email at posters(a)i-society.eu * You can submit your workshop or tutorial proposal at workshop(a)i-society.eu or tutorial(a)i-society.eu * You can submit your speaker's proposal at speakers(a)i-society.eu IMPORTANT DATES: *Abstract or Extended Abstract Submission Date: April 25, 2019 *Notification of Abstract or Extended Abstract Acceptance / Rejection: April 30, 2019 *Research Paper Submission Date: May 01, 2019 *Notification of Research Paper Acceptance / Rejection: May 15, 2019 *Camera Ready Paper Due: July 15, 2019 *Proposal for Workshops / Tutorials: May 01, 2019 *Notification of Workshop/Tutorials Acceptance / Rejection: May 05, 2019 *Poster / Demo Proposal Submission: May 01, 2019 *Notification of Poster / Demo Acceptance: May 05, 2019 *Early Bird Registration Deadline: June 01, 2019 *Late Bird Registration Deadline: July 01, 2019 *Conference Dates: October 22-24, 2019 For more details, please visit www.i-society.euIf you wish to unsubscribe from our newsletter, click http://r.confinfosoc.org/mk/un/cJt0lk_6hTiWU2mR1gcBlsWcuOzQ_Zs4QdpVvm0OQwTN…

2 1

question about GSoC 2019
by Aziz Mousa 18 Mar '19

18 Mar '19

hello there, I want to participate in boost project in the GSoC but I am confused a little bit and there is some points that I don't understand and I need some help here please * First : to be involve in this event if I don't have my own idea should I choose one project form the list like boost.GIL or boost.uBLAS as all or should choose a specific project inside one of them like project 1, or project 2 * second: if I choose project in boost.uBLAS should I be professional in machine learning? because I am still in the start of road in this field but I am work on it and will make progress as soon as possible * third : is there any thing should I do or submit before the student registration opens in GSoC website ? thanks in advance.

2 2

Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 17 Mar '19

17 Mar '19

Fellow C++, Boost, and WG21 Enthusiasts, lend me your ear! I write to inform you about exciting developments in C++ networking. First, a bit of background. Networking comes in three flavors: * Networking TS <https://cplusplus.github.io/networking-ts/draft.pdf> * Boost.Asio <https://www.boost.org/doc/libs/1_69_0/doc/html/boost_asio.html> * Standalone Asio <https://github.com/chriskohlhoff/asio> These three are for the most part identical, except that Asio flavors have additional features like ssl::stream and signal_set which are not in the TS, but will very likely appear in a future update or version. We've had Asio for over a decade now, but there is a shortage of experts. Some people believe this shortage is because Asio in particular (and thus, Networking TS since they have identical interfaces) is "difficult to use." I believe it is wrong to blame Asio for this. Concurrent programs in general are hard to write. This is applicable: "Unfortunately, today's reality is that only thoughtful experts can write explicitly concurrent programs that are correct and efficient. This is because today's programming models for concurrency are subtle, intricate, and fraught with pitfalls that easily (and frequently) result in unforeseen races (i.e., program corruption) deadlocks (i.e., program lockup) and performance cliffs (e.g., priority inversion, convoying, and sometimes complete loss of parallelism and/or even worse performance than a single-threaded program). And even when a correct and efficient concurrent program is written, it takes great care to maintain — it's usually brittle and difficult to maintain correctly because current programming models set a very high bar of expertise required to reason reliably about the operation of concurrent programs, so that apparently innocuous changes to a working concurrent program can (and commonly do, in practice) render it entirely or intermittently nonworking in unintended and unexpected ways. Because getting it right and keeping it right is so difficult, at many major software companies there is a veritable priesthood of gurus who write and maintain the core concurrent code." - Herb Sutter, "The Trouble with Locks", <http://www.drdobbs.com/cpp/the-trouble-with-locks/184401930> Although this was written in 2005 it is still relevant today. It is understandable that Asio will be the first target of anger and frustration when writing concurrent programs, since it is on the "front line" so to speak. There has also been a distinct shortage of *good* tutorials and examples for Asio. Articles or blog posts which teach you step by step, explaining everything, and giving example code which demonstrates best practices. Boost.Beast is my low-level HTTP/WebSocket library which builds on Boost.Asio: <https://github.com/boostorg/beast> In the original release of Beast, the documentation stated "prior understanding of Boost.Asio is required." However, field experience has shown that users ignore that requirement and attempt to write complex, concurrent programs as their first-time introduction to both Beast and Asio. Based on feedback from committee members, and to serve users better, the scope of Beast has been enlarged to include first-time users of networking. The upcoming Boost 1.70 release reflects this new scope and I am excited to announce some very nice things which you can access today. First of all, Beast documentation and examples no longer use the "boost::asio" namespace, they the namespace alias "net::". While this is cosmetic, it reinforces the notion when inspecting code that it is equally applicable to Boost.Asio, Asio, and Networking TS (identifiers which are not in the TS, such as signal_set, are still qualified with boost::asio). A new documentation page explains the three flavors of networking: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io.ht…> This is also explained in my 2018 CppCon presentation: <https://youtu.be/7FQwAjELMek?t=444> I have added a "Networking Refresher", a complete overview of networking from soup to nuts. No prior knowledge or understanding of networking is required, everything is explained in detail so if you want to learn this is the place to start. I also kept it short, but it is loaded with hyperlinks for further learning: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/as…> There was a recent paper in Kona, P1269R0 ("Three Years with the Networking TS") about difficulty of implementing timeouts. To address this, Beast now has a stream class which implements configurable timeouts for you, and callers no longer have to fiddle with timers manually anymore. Everything "Just Works." It achieves the P1269R0 author's goal of having timeouts "built-in to asynchronous operations", but in a way that fits in with the design of the TS: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/ti…> I feel that this `beast::basic_stream` serves as an existence proof that the current design of Networking TS is sound - the TS offers a flexible toolbox which lets you build your own framework the way that you want it, without making odd choices for you. We are still discovering ways of leveraging it to maximum use. The beast::websocket::stream also has built-in timeouts, but they are enhanced to support "idle pings" (keeping client connections alive) and everything is fully configurable: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_webso…> All you need to do to get sensible, suggested websocket timeouts is add one line of code after creating your stream: ws.set_option(websocket::stream_base::timeout::suggested( beast::role_type::server)); To address the cumbersome boilerplate of writing composed operations (specifically the need to propagate the associated allocator and associated executor, and to avoid invoking the completion handler from within the initiating function when the operation would complete immediately) Beast adds two new utility base classes, with plentiful documentation and examples throughout: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/wr…> There are two well-rounded examples which show you step by step how to write these things in a safe way: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/wr…> <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/wr…> I have a big, new open source project which implements a server, that uses the `system_context`, taking full advantage of native Windows and Mac OS system-level execution context features. To support this use case and industry feedback, the examples in Beast now default to being always thread-safe. All examples use a "strand", and leverage P1322R0 ("Networking TS enhancement to enable custom I/O executors"). Yes, this paper which was approved in Kona, is now implemented in both Boost.Beast, and Boost.Asio, including all of the Beast examples, so if you pick up Boost 1.70 (or the master branches from github) you can start playing with this as soon as you're done reading this message!! <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1322r0.html> We have an active #beast channel in the C++ Slack (https://slack.cpp.al) where experienced users can help, no question is too small! I hope you will join me and the rest of the Beast and Asio community in exploring what the very powerful Networking TS and Asio libraries have to offer, and build something great together! Regards P.S. Don't forget to star the repository! <https://github.com/boostorg/beast>

4 7

I am interested to participate in BOOST GSOC2019 project
by raghuchandra kanakamedala 17 Mar '19

17 Mar '19

I am raghuchandra studying 3rd year B.Tech at IIIT Hyderabad.It would be great to contribute to Boost.GIL: generic image library.I have ideas for both the projects.I had this course Digital Image Processing also done a project "Road detection from satellite images" based the paper attached.my implementation link on git https://github.com/savera2020/dip_project/.I have good skills in C++ programming. so can you provide the mail id of mentor so that we can go more deeper about the project.please consider my request to contribute to project.without a doubt i will give my best. Thanking You.

1 0

How should I teach a C++ college class?
by Joshua Marshall 17 Mar '19

17 Mar '19

I need some general input here. I'd like to pitch and run a semester long C++ course to students who have at least 1 year of programming experience. I'd like to have this open to open ended input. The biggest technical restrictions are that the University systems are running RHEL 7.4 (7.5?) with software collections devtoolset-8.

3 3

Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 15 Mar '19

15 Mar '19

On Fri, Mar 15, 2019 at 7:38 AM Stian Zeljko Vrba <vrba(a)quine.no> wrote: > I have an idea of how to accomplish the same in C++, and > it's not pleasant -- worker thread, promise/future, blocking > queue and CancelSynchronousIO. Cannot even use > std::async because CancelSynchronousIO needs a > target thread ID. Yes, yes! I see now...your ideas on how to implement it in C++ convince me more than anything that the documentation is the problem. There's no need for any of that stuff, the code you provided could be implemented in C++ using asio without too much fuss, and there are actually several ways to do it all of which are succinct and will work wonderfully.

1 0

Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 15 Mar '19

15 Mar '19

On Fri, Mar 15, 2019 at 7:19 AM Stian Zeljko Vrba <vrba(a)quine.no> wrote: > > I believe it is wrong to blame Asio for this. > > I disagree. Recently, I've been coding parallel, including networked & > asynchronous, programs in C# and Java, and the experience has been a JOY. You > get threads, executors, synchronization primitives, tasks, cancellation, > monadic futures and concurrent (blocking and non-blocking) data structures > out of the box with the platform, plus a myriad of extensions as libraries. > As for executors, you don't need to be bothered with them unless you really > want to for some reason. > If you were to compare POSIX or BSD sockets to C# and Java, you would say exactly the same things. Asio (like Beast) is a low-level, portable abstraction of I/O. You can BUILD "threads", "executors", "synchronization primitives", "tasks", "cancellation", "monadic futures", and "concurrent data structures" with it. Does this mean OS-level sockets are the wrong abstraction? Of course not. The reason C# seems "ahead" of C++ is two-fold: 1. WG21 goofed up by delaying networking 2. C# is not developed through the International Standards Process These mistakes are being fixed though, and you will see library support in C++ catch up by leaps and bounds. And when we finally get these things (built on top of Asio/Networking TS, which has proven over and over to be the correct low-level abstraction) it will be better than C#, Java, or Rust. Compare the documentation for Vertx (vertx.io) or netty (both Java toolkits > for writing asynchronous reactive programs) with that of asio. > Yes I agree, there is a lack of documentation and especially tutorials for beginners (which I am trying to fix). This has nothing to do with whether Asio is the right portable, low-level abstraction (it is) but the lack of guidance from the author could lead you to believe incorrect things about the lib. Once I attempted to write an asio service, tried to understand the simple > example from the documentation, and I gave up. I used a thread, blocking > call and CancelSynchronousIO (and I consider myself fortunate to develop > for Windows only that has it). > The documentation on services is particularly scant. There is no explanation of what they are for, how to use them, best practices, or even "Frequently Asked Questions." I was able to figure it out though, but I am able to focus all of my time on it. > Asio _is_ a relatively nice wrapper around socket and serial port APIs, > but that's about it > Yes now you're getting close to an accurate description. More correct would be to say that Asio provides robust abstractions of buffers, dynamic buffers, synchronous I/O, and asynchronous I/O. Networking is a subset of that (but not the only part, see signals and serial ports, and soon file I/O). > IMO. On the other hand, I could have written the same wrappers around > native APIs in two days and not haul along what I consider the baggage of > technical debt that is asio in the codebase. > There is no API technical debt. That is to say, that the interfaces are modern and up-to-date. You could argue that particular implementations such as Boost.Asio have extra code to provide C++03 compatibility, but this has nothing to do with the soundness of the design. As these interfaces are part of a TS, there will be implementations in gcc and clang appearing shortly (if not already so). These will be written from scratch so there will be no support for older C++. > Conclusion, if any: many people just want/need thread per client and > synchronous IO for simplicity, but until asio/networking TS provide for > timeouts and cancellation of synchronous requests, it's a wrong tool for > those people, me included. > If you define struct sync_socket { net::io_context ioc_; net::ip::tcp::socket_; net::steady_timer timer_; ... template<class Buffers> std::size_t write_some (Buffers const& b); }; You can easily implement timeouts in `write_some` thusly: template<class Buffers> std::size_t sync_socket:: write_some (Buffers const& b, error_code& ec) { std::size_t n; timer_.expires_after(seconds(30)); timer_.async_wait( [&](error_code ec) { socket_.cancel(ec): }); socket_.async_write_some(b, [&](error_code ec_, std::size_t n_) { ec = ec_; n = n_; }); ioc_.run(); return n; } Now, you can use `sync_socket` with all the usual sync write operations like `net::write`, and get timeouts. Thanks

1 0

Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 15 Mar '19

15 Mar '19

On Fri, Mar 15, 2019 at 2:45 AM Cristian Morales Vega <cristian(a)samknows.com> wrote: > I have not used the synchronous API at all. But section 3.1 of P1269R0 > seems to make a good point about the lack of timeouts in synchronous > calls, doesn't it? > beast::basic_stream makes using timeouts in the async API way simpler, > but is the sync API really basically unusable because of the lack of > timeouts thing? Synchronous APIs are perfectly fine. Asio defines SyncReadStream and SyncWriteStream named requirements, allowing for generic algorithms to be implemented. Not everything is a socket (for example, a serial port). A synchronous stream represents the reliable, in-order delivery of bytes using functions that block, nothing more and nothing less. For example, serial file I/O can be represented using a synchronous stream. If the synchronous stream requirements mandated timeouts, it would eliminate a broad set of implementations (including sockets on some platforms).

1 0

Status of Disjoint Sets ?
by Brian Kuhl 15 Mar '19

15 Mar '19

Disjoint Sets is in the last few releases, has it's own test suite and github archive, but isn't mentioned on the documentation page? An oversight, or intentional? https://www.boost.org/doc/libs/1_69_0/ I see a defect that says it should move into Graph, is that part of the puzzle? https://github.com/boostorg/disjoint_sets/issues Brian

2 1

Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Mike 15 Mar '19

15 Mar '19

> All in all nice intro, unfortunately it requires users to understand > templates quite well, but honestly not sure if it is avoidable, with a > gazillion customization points in ASIO. Anyone aware of a wrapper library around ASIO that doesn't offer all those customization points and maybe not the full functionality/ efficiency but is easier to use? Am 15.03.19, 01:09, Ivan Matek via Boost <boost(a)lists.boost.org> schrieb: Here are comments from somebody who "knows C++" but does not know a lot about NW and has read only the 1st <[1]https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/ using_io/asio_refresher.html> page. // get iterators representing the range of characters in the buffer auto begin = range::begin(buffer.data()); auto end = range::end(buffer.data()); Quite a weird pattern, where buffer does not have member begin, end. Maybe a sentence or two describing the rationale and complexity would be nice. I know it is O(1), but it is weird that begin/end are called on pointer. std::size_t read_lineI am tired, but is this function O(n^2)? cb += bytes_transferred; // adjust the pointer and sizeI would maybe switch to write instead of write_some to keep the code shorter, and mention write_some as another option in text. [](error_code ec, std::size_t bytes_transferred) For learning purposes I would capture something in lambda by value and note that reference capture would be buggy. using type = std::allocator<void>; Personal preference: not a fan of typedefs for relatively short types used once. All in all nice intro, unfortunately it requires users to understand templates quite well, but honestly not sure if it is avoidable, with a gazillion customization points in ASIO. _______________________________________________ Unsubscribe & other changes: [2]http://lists.boost.org/mailman/listinfo.cgi/boost References 1. https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/as… 2. http://lists.boost.org/mailman/listinfo.cgi/boost

1 0

Coordinating Boost Releases with compiler releases
by Marshall Clow 14 Mar '19

14 Mar '19

In the thread "MSVC 2019 and 1.70 beta", there has been a discussion about what to do about support for MSVC 2019, which is due to be released right about the same time that Boost 1.70. One person suggested that we delay the boost release until after the MSVC release (I think the suggestion was "May"). This general question has been discussed before (several times), since tools get released fairly often - and so does Boost. In general, I am not in favor of delaying boost releases in order to add support for 'about to be released' development tools. There are two main reasons for this: * There's always another compiler / tool about to be released. Clang 8 is imminent - currently at RC5. GCC 9.1 is scheduled to be released in early May. * Boost releases happen every four months. August is not really that far off. People who want support for tool XXXX can use "the trunk", getting it either from git or from bintray. [ Everyone knows about the tarballs at bintray, right? https://dl.bintray.com/boostorg/master/ ] Also, if we were to delay the boost release until May, then what would happen to the August release? The release process for 1.71.0 is scheduled to start at the end of June. -- Marshall

5 7

[filesystems]
by Florian Lindner 14 Mar '19

14 Mar '19

Hello, I have this innocent piece of code: namespace fs = boost::filesystem; auto path = getFilename(); // returns a string fs::create_directories(fs::path(path).parent_path()); std::ofstream ofs(path + "~"); ofs << info; ofs.close(); fs::rename(path + "~", path); which causes the exception: boost::filesystem::rename: No such file or directory: "../9f/061b4f7a5e529c964659226eedd4e5~", "../9f/061b4f7a5e529c964659226eedd4e5" However, I have no idea how that could happen. I use the rename, so that a reading process never sees an empty file, but only no file or filed with info. Is there any race involved between ofs.close() and fs:rename()? The code was executed on a distributed network filesystem (lustre). Any ideas anyone? Thanks, Florian

5 9

Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 14 Mar '19

14 Mar '19

On Thu, Mar 14, 2019 at 10:50 AM james <dirtydroog(a)gmail.com> wrote: > This is excellent news. Timeouts are ASIO's biggest downfall. I'll definitely check it out. > If it's low level, and performant enough, then it paves the way for ASIO-ed connectors for things like Redis and ZeroMQ. Thanks! And we are very happy to answer questions, feel free to open an issue or come to the #beast Slack channel. Regards

1 0

Cannot serialize pointer through base without void_cast_register and register_type.
by Nicolas Guillot 14 Mar '19

14 Mar '19

Hello. *** CONTEXT *** I use your serialization library since several years on linux (gcc). Now, I'm moving to windows (_MSC_VER == 1600) (boost 1.55, but same issues on boost 1.69). For my example, I use a class A in a DLL, another class B inheriting from A in its DLL and an exe, linked to those DLLs, which serializes a B object, through its A base. _______ | A | ------- /_\ | | _______ | B | ------- I make a class serializable like that (I summurize on purpose (no #include, ...)). For A it's the same thing, but it has no base class. ----> B.h ---------------------------------------- #ifdef B_EXPORTS #define B_DLL __declspec(dllexport) #else #define B_DLL __declspec(dllimport) #endif class B_DLL B: public A { public: B(); virtual ~B(); private: friend class boost::serialization::access; template <class Archive> void serialize(Archive & ar, const unsigned int version); int i; }; BOOST_CLASS_EXPORT_KEY(B) ----> B.cpp ---------------------------------------- B::B() : i(123) {} B::~B() {} template <class Archive> void B::serialize(Archive & ar, const unsigned int) { ar & SERIALIZE_BASE(ClassA); ar & SERIALIZE(i); } #define FULL_SCOPED_SERIALIZABLE_CLASS B #include "Common/InstanciateSerializationTemplate.h" ----> InstanciateSerializationTemplate.h ---------------------------------------- This file purpose is to instanciate the template B::serialize methods for each archive type, and to register the class. Here is its contents (once again, no namesapce nor include to make it easier to read): // explicit instantiate code for all archive types expected to be use: // MUST COME BEFORE BOOST_CLASS_EXPORT_IMPLEMENT // binary: template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<binary_iarchive>(binary_iarchive & ar, const unsigned int version); template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<binary_oarchive>(binary_oarchive & ar, const unsigned int version); // XML: template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<xml_iarchive>(xml_iarchive & ar, const unsigned int version); template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<xml_oarchive>(xml_oarchive & ar, const unsigned int version); // TXT: template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<text_iarchive>(text_iarchive & ar, const unsigned int version); template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<text_oarchive>(text_oarchive & ar, const unsigned int version); BOOST_CLASS_EXPORT_IMPLEMENT(FULL_SCOPED_SERIALIZABLE_CLASS) *** MY ISSUE *** All that stuff works in linux, gcc, but not in Windows. If I write in my exe this serialization code: std::ofstream ofs; ofs.open("D:\\TestSerial.xml"); boost::archive::xml_oarchive ar(ofs); shared_ptr b = shared_ptr(new B()); shared_ptr<A> a = b; try { ar << SERIALIZE(a); } catch (boost::archive::archive_exception& ex) { std::cout << "Serialization to stream error, what: " << ex.what() << std::endl; } catch (...) { std::cout << "Catch ... Serialization to stream error" << std::endl; } ofs.close(); With this code, I have an archive_exception: "unregistered class - derived class not registered or exported". I have to write the serialization like that: ar.register_type(static_cast<B*>(0)); boost::serialization::void_cast_register(static_cast<B*>(0), static_cast<A*>(0)); ar << SERIALIZE(a); *** QUESTION *** At least, my question: I cannot do like that: what I would like to achieve: when a new class is made serializable like above, I expect the class to be registered automatically (probabley with BOOST_CLASS_EXPORT_IMPLEMENT in InstanciateSerializationTemplate.h). It's too painfull to write the register_type and void_cast_register each time I want to serialize. What am I missing? Thank you very much for any help or recommandations. Nico

1 1

Re: [boost] MSVC 2019 and 1.70 beta
by Peter Dimov 14 Mar '19

14 Mar '19

> Tom Kent wrote: > > > Build support for VS 2019 RC (msvc-14.2) is on develop in boost build. > > Do we want to merge that to master for the release? > > I think we do. 1.70 and 2019 will release at about the same time. In fact looking at the calendar, 2019 will release (Apr 2) just before 1.70 is closed for release (Apr 3.)

3 3

boost-install-ing zlib (Was: Re: [Release] Boost 1.70.0 Beta 1 Release Candidate 2)
by Peter Dimov 13 Mar '19

13 Mar '19

> I'll need to try and see what happens with <source> in user-config. > Probably nothing good, because one would expect neither <build-name> nor > <tag> to be specified in such a case. If I remove the check for ZLIB_SOURCE, and just do alias boost_zlib : /zlib//zlib ; libraries-to-install += boost_zlib ; unconditionally in libs/iostreams/build/Jamfile, this is what happens: - when `using zlib : : <source>C:/Projects/zlib-1.2.11 ;` is in user-config, the default `b2 install` fails because `address-model=32,64 variant=debug,release` conflict as all try to build `libz.lib`. When address-model=32 variant=debug is given, `libz.lib` is installed in C:\Boost\lib, and the CMake configuration for boost_zlib correctly points to it. - when using a prebuilt `using zlib : : <include>C:/Projects/include <search>C:/Projects/lib <name>zlib-8 ;`, the CMake configuration file for boost_zlib points to "${_BOOST_LIBDIR}/zlib-8", which is not correct.

2 2

(no subject)
by Marshall Clow 13 Mar '19

13 Mar '19

Boost release 1.70.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.70.0.beta1/source/> The SHA256 checksums are as follows: dbf89645e509acb2e53eac3c633834f1dec80bd8622e6e652a9741dcf0807f17 ./boost_1_70_0_b1.7z 957b984b58656a3ec00661ecad7ef82e3a094bad36e37b9e6624843237854679 ./boost_1_70_0_b1.tar.bz2 76d149c1fb9e8a5ceb3bc1e5587edc40fa79a43e8b990d877c2210f0382b9421 ./boost_1_70_0_b1.tar.gz 71e990b2c26880521fd98459b184ee172ce1c46dcf554b6eaab7776b8b6369a6 ./boost_1_70_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_70_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

2 3

[rational] permission to merge cmake change?
by James E. King III 13 Mar '19

13 Mar '19

Before 1.70.0 beta started, some cmake changes from Mike Dev were merged into rational. There was a typo in one of the cmake options (BOOST_RATIONA_INCLUDE_TESTS). This does not affect code nor the boost build system. Would it be okay to merge this now or should I wait? https://github.com/boostorg/rational/pull/35 Thanks. - Jim

1 1

[release] Boost 1.70.0 Beta 1 Release Candidate 3
by Marshall Clow 12 Mar '19

12 Mar '19

A new release candidates for the first 1.70.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.70.0.beta1.rc3/source/ Changes since RC2: * Relative paths for --prefix, --libdir, etc. are now bound relative to the current working directory, instead of being relative to the Jamfile. Thanks to Tom Kent for the report, and Steven and Peter for the fixes. Changes since RC1: * The Jamfile for Boost.Predef has been updated to allow running the tests from /status. Thanks to mike.dev(a)gmx.de for the report, and to Rene for the fix. The release notes are not yet available. The SHA256 checksums are as follows: dbf89645e509acb2e53eac3c633834f1dec80bd8622e6e652a9741dcf0807f17 ./boost_1_70_0_b1_rc3.7z 957b984b58656a3ec00661ecad7ef82e3a094bad36e37b9e6624843237854679 ./boost_1_70_0_b1_rc3.tar.bz2 76d149c1fb9e8a5ceb3bc1e5587edc40fa79a43e8b990d877c2210f0382b9421 ./boost_1_70_0_b1_rc3.tar.gz 71e990b2c26880521fd98459b184ee172ce1c46dcf554b6eaab7776b8b6369a6 ./boost_1_70_0_b1_rc3.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

5 8

[Release] Boost 1.70.0 Beta 1 Release Candidate 2
by Marshall Clow 12 Mar '19

12 Mar '19

A new release candidates for the first 1.70.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.70.0.beta1.rc2/source/ Changes since the last RC: * The Jamfile for Boost.Predef has been updated to allow running the tests from /status. Thanks to mike.dev(a)gmx.de for the report, and to Rene for the fix. The release notes are not yet available. The SHA256 checksums are as follows: 26dba8156ad08041c6da52c84a2654aefda292180afe3546a9a74dda0dfb3781 ./boost_1_70_0_b1_rc2.7z ee794d98429bc2bfae054f2fab6fde53ea95f7c5967d8b267e57c894a4d46e57 ./boost_1_70_0_b1_rc2.tar.bz2 bca5f189d87b26ab903838dee2fd4c54e9043bd35d27b8923cdef42651ae7261 ./boost_1_70_0_b1_rc2.tar.gz 6c8f3af4e64d3a04a3d3a5e98499d2f6bb460ad82c1f33ff7da800b5ab182b0b ./boost_1_70_0_b1_rc2.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

4 25

Re: [boost] [Boost-users] [release] Boost 1.70.0 Beta 1 Release Candidate 1
by Tom Kent 11 Mar '19

11 Mar '19

On Fri, Mar 8, 2019 at 9:44 PM Tom Kent <lists(a)teeks99.com> wrote: > > > On Fri, Mar 8, 2019 at 8:57 PM Tom Kent <lists(a)teeks99.com> wrote: > >> >> >> On Fri, Mar 8, 2019 at 6:42 PM Marshall Clow via Boost-users < >> boost-users(a)lists.boost.org> wrote: >> >>> On Fri, Mar 8, 2019 at 10:21 AM Marshall Clow <mclow.lists(a)gmail.com> >>> wrote: >>> >>>> The release candidates for the first 1.70.0 beta release are now >>>> available at: >>>> >>>> https://dl.bintray.com/boostorg/beta/1.70.0.beta.1.rc1/source/ >>>> >>>> The release notes are not yet available. >>>> >>>> The SHA256 checksums are as follows: >>>> >>>> a7c570d6307d05dc8d45a3b4c69a0afdcba2b22eac0c4da4d496559f53db7b89 >>>> ./boost_1_70_0_b1_rc1.7z >>>> 4b91b9a203cf12f6001cf39de83c7cc005fbc5390e2b4b2fc29ce7b19c0537a7 >>>> ./boost_1_70_0_b1_rc1.tar.bz2 >>>> 460dd6499bba9df04c6bfa219b26097bad803b8758304ba45f2fc291aa42c96e >>>> ./boost_1_70_0_b1_rc1.tar.gz >>>> f209c9a086ed2c7882a0bc8755792f436eb141eaeb8c823ed57295ca9ce25b93 >>>> ./boost_1_70_0_b1_rc1.zip >>>> >>>> As always, the release managers would appreciate it if you download >>>> the candidate of your choice and give building it a try. Please report >>>> both success and failure, and anything else that is noteworthy. >>>> >>> >>> >> I'm having a problem with B2 in this release. >> >> For many releases now, I have run a command such as: >> b2 -j16 --build-type=complete toolset=msvc-10.0 address-model=64 >> architecture=x86 --prefix="./" --libdir=lib32-msvc-10.0 >> --includedir=temp_inc install >> >> to get the windows builds of each toolset. For the install, I set the >> prefix as the current directory, so that I'll get a lib{arch}-msvc-{ver} >> directory for each toolset in there. However, with this 1.70 release, it >> seems to ignore my prefix and put the headers in >> libs/headers/build/temp_inc/boost-1_70/boost, instead of >> temp_inc/boost-1_70/boost. For the libraries, it scattered them throughout >> the build in directories such as libs/coroutine/build/lib32-msvc-10.0/. >> >> Any thoughts on what might be causing this? Am I using the --prefix >> --libdir and --inlcudedir correctly? Or at least not badly enough to >> warrant this? >> > > Also, even though I have BZIP2_SOURCE and ZLIB_SOURCE set, I'm not seeing > the appropriate bzip2 and zlib libraries being generated. > > After updating my scripts to us "staging" instead of "install" to avoid the above issue, I was able to get everything else to build successfully for Visual Studio (msvc-10.0 through msvc-14.1, note this is the first release I haven't built against msvc-8.0 and 9.0). The only exception being the lack of bzip2 and zlib support mentioned above. toolset arch compile Link Execute msvc-10.0 32 X X X msvc-10.0 64 X X X msvc-11.0 32 X X X msvc-11.0 64 X X X msvc-12.0 32 X X X msvc-12.0 64 X X X msvc-14.0 32 X X X msvc-14.0 64 X X X msvc-14.1 32 X X X msvc-14.1 64 X X X Compile means that the b2 command completed without errors Link means that visual studio was able to link a sample executable to a library (libboost_thread-vcXXX-mt[-gd]-1_XX.lib) generated Execute means that the linked program executed without errors. Full build logs can be found at https://gist.github.com/teeks99/0aeed77c9251ba02090d9ab7372e2c73 Tom

4 4

Regarding GSoc 2019
by karmanya grover 11 Mar '19

11 Mar '19

Sir/Madam, I am a Google Summer of Code 2019 aspirant. This email is regarding inquiry of possible projects that I am interested in. Please provide the specifics for following questions. In Boost.uBLAS library, I want to know if there's some work done for python integration previously or not. I also want to inquire about Boost Astronomy library. Looking into git repository, I found that this library is fairly new. What are the aspects hoped to be achieved for this library as a full efficient and mathematical friendly. I have always been interested in Astrophysics and applying those concepts in problem solving. Apart from that, What were the previous works done in Boost.Real library by past GSoc'ers. with regards, Yours sincerely, Karmanya Grover (B.E). NSUT

3 2

[release] 1.70 Windows binaries
by Sean Farrow 10 Mar '19

10 Mar '19

Hi, I know there is a discussion regarding building 1.70 with zlib in another thread, but wondered whether there are any binaries available for msvc without zlib for the 1.70 beta rc1/2? Kind regards Sean.

1 0

[variant2] documentation request
by Andrzej Krzemienski 10 Mar '19

10 Mar '19

Hi Peter, Given that the never-empty guarantee appears to be at the heart of the motivation for boost::variant2, I would suggest to: 1. put in the documentation some motivation behind pursuing the never-empty guarantee. 2. Make it clear that never-empty guarantee is not a strong exception-safety guarantee. 3. Describe the algorithm for achieving the guarantee. The current description does not seem to cover all interesting cases, and I found the behavior quite surprising. For instance, the variant's move assignment will sometimes use T's move assignment rather than move constructor when changing the variant's type, as in the following example: https://wandbox.org/permlink/GDRyS54bpdLP7GVa Regards, Andrzej

10 32

[gsoc19] Seeking Guidance along with mentor for Boost.GIL Project
by Keshav Gupta 10 Mar '19

10 Mar '19

Respected Sir, I am Keshav Gupta currently doing my B.E. in Computer Engineering from Thapar University, Patiala, Punjab, India. Actually I want to participate in GSOC19 and want to work with you during that period. Actually I am interested in implementing various Image Processing algorithms using BOOST.GIL. and I think that I can perfectly work upon this as I am also currently doing my research in the area of Fingerprint Matching and you absolutely know that this definitely includes the usage of image processing algorithms and that why I am interested for this as I know I have the proper knowledge of C++ along with image processing algorithms. Kindly guide me how to proceed further so as to increase my chances of getting being selected in GSOC19. Also please tell me any other way how to contact the mentor of this project as I have mailed him certain number of times but didn't get any response. Waiting for your reply Regards Keshav Gupta

2 1

Re: [boost] [Release] Boost 1.70.0 Beta 1 Release Candidate 2
by Peter Dimov 09 Mar '19

09 Mar '19

> Tom Kent wrote: > > > * Can't create libraries for bzip2 and zlib (showstopper? anyone else > > seeing this?) > > I haven't seen your initial report of this issue (on the users list?) but > it's probably caused by this change: > > https://github.com/boostorg/build/commit/5ad92cd76ff393792f30aa50688c95eff2… Or maybe not. This is in 1.69.0, so it can't be the cause.

1 0

[release] Boost 1.70.0 Beta 1 Release Candidate 1
by Marshall Clow 09 Mar '19

09 Mar '19

The release candidates for the first 1.70.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.70.0.beta.1.rc1/source/ The release notes are not yet available. The SHA256 checksums are as follows: a7c570d6307d05dc8d45a3b4c69a0afdcba2b22eac0c4da4d496559f53db7b89 ./boost_1_70_0_b1_rc1.7z 4b91b9a203cf12f6001cf39de83c7cc005fbc5390e2b4b2fc29ce7b19c0537a7 ./boost_1_70_0_b1_rc1.tar.bz2 460dd6499bba9df04c6bfa219b26097bad803b8758304ba45f2fc291aa42c96e ./boost_1_70_0_b1_rc1.tar.gz f209c9a086ed2c7882a0bc8755792f436eb141eaeb8c823ed57295ca9ce25b93 ./boost_1_70_0_b1_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

4 9

Interest in GSoC Project
by Kanav Gupta 09 Mar '19

09 Mar '19

Hello, I am third-year undergrad research student at International Institute of Information Technology, Hyderabad. I would like to contribute to Boost.GIL as a part of GSoC '19. I am currently working on a research project involving image processing and have also worked on various projects involving C++ so I guess I am competent for the project. Can you please guide me on how should I proceed? Thanks and Regards, Kanav Gupta

1 0

[release] 1.70.0 closed for major changes
by Marshall Clow 07 Mar '19

07 Mar '19

The master branch is now closed for new libraries and breaking changes, and will be closing for the beta in one week. Also, if you're ready, you can also add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… > After editing the release notes, you should get a form to create a pull request, remember to submit it, otherwise I won't see your change. As always, the calendar for the release cycle is available at: https://www.boost.org/development/ Thanks, -- The Boost Release Team

7 9

[Release 1.70] Master branch is now closed for the beta
by Marshall Clow 07 Mar '19

07 Mar '19

Except with explicit permission by a release manager. Do whatever you want on develop, just don't change master. We'll re-open master after the beta. As always, check the calendar at https://www.boost.org/development 6-Mar: Boost 1.70.0 closed for all changes 13-Mar: Boost 1.70.0 beta; master branch re-opened 2-Aug: Release closed for all changes, except by permission of a release manager. 3-Apr: Boost 1.70.0 closed for all changes 10-Apr: Boost 1.70.0 release -- The release managers

2 1

[build] Boost.Build/develop broken with msvc?
by John Maddock 07 Mar '19

07 Mar '19

Currently I see: D:/data/boost/boost/tools/build/src/tools\msvc.jam:1388: in configure-really *** argument error * rule generate-setup-cmd ( version : command : parent : options * : cpu : global-setup ? : default-global-setup-options : default-setup ) * called with: ( 14.16.27023 14.11.25503 : D:/compilers/visual studio/2017/VC/Tools/MSVC/14.11.25503/bin/HostX64/x64 : D:\compilers\visual studio\2017\VC\Tools\MSVC\14.11.25503\bin\HostX64 : <command>D:\compilers\visual studio\2017\VC\Tools\MSVC\14.16.27023\bin\Hostx64\arm\cl.exe <command>D:/compilers/visual studio/2017/VC/Tools/MSVC/14.11.25503/bin/HostX64/x64/cl.exe : i386 : : x86 : vcvars32.bat ) * extra argument 14.11.25503 D:/data/boost/boost/tools/build/src/tools\msvc.jam:1003:see definition of rule 'generate-setup-cmd' being called D:/data/boost/boost/tools/build/src/tools\msvc.jam:393: in configure D:/data/boost/boost/tools/build/src/tools\msvc.jam:345: in msvc.init D:/data/boost/boost/tools/build/src/build\toolset.jam:44: in toolset.using D:/data/boost/boost/tools/build/src/build\project.jam:1104: in using C:\cygwin64\home\John Maddock\user-config.jam:46: in modules.load D:/data/boost/boost/tools/build/src\build-system.jam:255: in load-config D:/data/boost/boost/tools/build/src\build-system.jam:453: in load-configuration-files D:/data/boost/boost/tools/build/src\build-system.jam:607: in load D:\data\boost\boost\tools\build\src/kernel\modules.jam:295: in import D:\data\boost\boost\tools\build\src/kernel/bootstrap.jam:139: in boost-build D:\data\boost\boost\boost-build.jam:17: in module scope Master is fine BTW. Best, John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 3

[interprocess] support for a new synchronisation mechanism
by Dudi Likvornik 06 Mar '19

06 Mar '19

Hi, My name is David, I would like to suggest a new synchronisation mechanism based on linux futex. as far as I saw, its not being supported as of now with in the interprocess communication library. One suggestion is to support a mutex, here is an example, possible partial implementation, based upon the following paper: http://dept-info.labri.fr/~denis/Enseignement/2008-IR/Articles/01-futex.pdf Mutex::Mutex(): m_word(UNLOCK) {} void Mutex::lock() { int lockState = UNLOCK; if(std::atomic_compare_exchange_strong(&m_word, &lockState, static_cast<int>(LOCK_SINGLE)) == false) { if(lockState != LOCK_MANY) lockState = std::atomic_exchange(&m_word, static_cast<int>(LOCK_MANY)); while(lockState != UNLOCK) { #if defined(__linux) syscall(SYS_futex, &m_word, FUTEX_WAIT, LOCK_MANY, nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wait is not being supported by current platform"); #endif lockState = std::atomic_exchange(&m_word, static_cast<int>(LOCK_MANY)); } } } void Mutex::unlock() { if(std::atomic_fetch_sub(&m_word, 1) == LOCK_SINGLE) return; m_word = UNLOCK; #if defined(__linux) syscall(SYS_futex, &m_word, FUTEX_WAKE, 1, nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wake is not being supported by current platform"); #endif } bool Mutex::try_lock() { int lockState = UNLOCK; return std::atomic_compare_exchange_strong(&m_word, &lockState, static_cast<int>(LOCK_SINGLE)); } ————————————————————————————————————————————————————————— And a conditional variable: Condition::Condition(): m_command(SLEEP), m_waitersCount(0){} void Condition::signal(Command command) { m_wakeLock.lock(); if(m_waitersCount == 0) { m_wakeLock.unlock(); return; } m_command.store(command, std::memory_order_relaxed); #if defined(__linux) syscall(SYS_futex, &m_command, FUTEX_WAKE, command == NOTIFY_ONE ? 1 : std::numeric_limits<int>::max(), nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wake is not being supported by current platform"); #endif while(m_command.load(std::memory_order_relaxed) != SLEEP && m_waitersCount.load(std::memory_order_relaxed) != 0){} m_wakeLock.unlock(); } void Condition::wait(std::unique_lock<core::Mutex> &lock) { m_waitersCount++; lock.unlock(); while(true) { while(m_command.load(std::memory_order_relaxed) == SLEEP) #if defined(__linux) syscall(SYS_futex, &m_command, FUTEX_WAIT, SLEEP, nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wait is not being supported by current platform"); #endif int fromCommand_one = NOTIFY_ONE; if(m_command.compare_exchange_strong(fromCommand_one, static_cast<int>(SLEEP), std::memory_order_relaxed)) { m_waitersCount--; lock.lock(); return; } else if(m_command.load(std::memory_order_relaxed) == NOTIFY_ALL) { if(m_waitersCount.fetch_sub(1, std::memory_order_relaxed) == 1) m_command.store(SLEEP, std::memory_order_relaxed); lock.lock(); return; } } } ConditionVariable::ConditionVariable() {} void ConditionVariable::wait(std::unique_lock<core::Mutex> &lock) { m_condition.wait(lock); } void ConditionVariable::notify_one() { m_condition.signal(Condition::NOTIFY_ONE); } void ConditionVariable::notify_all() { m_condition.signal(Condition::NOTIFY_ALL); } class ConditionVariable { public: ConditionVariable(); ConditionVariable(const ConditionVariable&) = delete; ConditionVariable& operator=(const ConditionVariable&) = delete; void wait(std::unique_lock<Mutex>& lock); template<typename Predict> void wait(std::unique_lock<Mutex>& lock, const Predict& predict) { while(predict() == false) m_condition.wait(lock); } void notify_one(); void notify_all(); private: Condition m_condition; }; Your thoughts of the idea, if any. p.s. Please be soft, its my first post ever :).

1 0

Boost.uBLAS [gsoc19]
by Sarthakag 06 Mar '19

06 Mar '19

Hello, I am Sarthak Agarwal, 3rd-year undergraduate student from Birla Institute of Technology and Science, Pilani - Goa, India currently pursuing a double major MSc. Mathematics and B.E. Computer Science and Engineering. I am an active Competitive Programmer on various online judges for the last 4 years. I am comfortable in C/C++(STL) and Python(Django). I wish to contribute to Boost.uBLAS, specifically to Project 4 on implementing non-negative matrix factorization(NMF). I would also like to know if there are any upcoming ideas to implement in Boost.intrusive. I have completed the Boost Competency test and learned a lot while doing it. How can I share it for valuable feedback? I look forward to your guidance. Sarthak Agarwal -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

1 0

Regarding GSOC'19
by Keshav Gupta 05 Mar '19

05 Mar '19

Hi I am Keshav Gupta from India and wanted to work with Boost during GSOC 2019 on the major topic of Boost GIL. So can you tell me how to proceed with? Regards Keshav Gupta

1 0

[variant2] Need rationale for never-empty guarantee
by Andrzej Krzemienski 04 Mar '19

04 Mar '19

Hi Peter, Thank you for writing and sharing this implementation of variant. I am sorry if I am bringing back an issue that has been already discussed and solved before, but I do not understand the rationale behind doing compromises in order to provide the never-empty guarantee. The short rationale provided in Boost.Variant library: https://www.boost.org/doc/libs/1_69_0/doc/html/variant/design.html#variant.… was provided before we got C++11 the moved-from state in the language. Today, it should come as no surprise to programmers that a type might be in a "moved from" state where only a limited interface of an object can be used. The guarantee provided by variant's assignment is not a strong exception safety guarantee: it is possible that my variant has value A, I want to assign value B, and (due to an exception) I end up with value C. If this happens, the only thing I can reasonably do is to either abandon whatever I was doing or reset the variant to the state that I need. So the guarantee that it is not left empty does not seem to be of much use. But the cost to be paid is noticeable. I think that this question should be addressed in the documentation. Regards, Andrzej

13 51

[gsoc19][astronomy] Code for review
by Avinal Kumar 04 Mar '19

04 Mar '19

where should I submit my code for programming competency test ??

2 1

Mentors invitations
by David Bellot 04 Mar '19

04 Mar '19

Dear Boost C++ mentors, it seems we only have 5 mentors this year. It's not a lot. Usually, we have one student per mentor, but we also have 6 to 8 students as well. We need at least one or two mentors more. I've just sent the invite from the GSOC website to become a mentor. If you didn't receive it yet, it's surely because I forgot your name. Can you please send me a reminder now with your correct email address? If you didn't propose to become a mentor but want to now, please let me know as well. Cheers, David

1 0

GSoC 2019 Introduction|Boost.Python-C++-Python Integration Project
by Roopkatha Samanta 04 Mar '19

04 Mar '19

Hi, I am Roopkatha Samanta, studying in 2nd year CSE (undergrad) at Jadavpur University, Kolkata, India. I am very well versed with programming languages like C, C++, Python and Java. I am very much into mathematics too and also interested in machine learning and deep learning. Presenly I am working on two projects in domain of Image Processing as my undergrad project and also trying to develop games on my own. I would like to contribute toBoost.Python-C++-Python Integration Project as my GSoC 2019 Project. Kindly guide me through the process on how to start. Regards, Roopkatha Samanta

2 1

[gsoc19] Logo
by Cem Bassoy 04 Mar '19

04 Mar '19

Hi, is there a chance to change the current logo on the organization list https://summerofcode.withgoogle.com/organizations/?sp-page=5 with https://de.wikipedia.org/wiki/Boost_(C%2B%2B-Bibliothek)#/media/File:Boost.… The current image on the google summer of code page does not look too good and all other organization have smooth ones. Best Cem

5 6

GSoC 2019
by Shourya IIT B 04 Mar '19

04 Mar '19

Respected Sir, I am Parashuram Shourya from India. Currently, I am doing my Master’s in Geoinformatics from Centre of Studies in Resources Engineering(CSRE), Indian Institute of Technology Bombay(IITB). I have a Bachelor's degree in Computer Science and Engineering. Currently, I am learning Machine Learning and High-Performance Computing. I have vast programming experience in C, C++, Python I would love to contribute to The Qt Project in the upcoming Google Summer of Code 2019. I would be very grateful to get any directions to start with so that I can pursue and participate in GSoC 2019 with your organization.

2 1

GSoC 2019: we're in again!
by David Bellot 04 Mar '19

04 Mar '19

Dear Boost community, this year again, Boost C++ has been accepted as a mentor organization for the Google Summer of Code 2019. We are very happy to be part of this program every year because it brings talented students and a substantial amount of money to our organization to support our work toward the best libraries in C++. If you want to be a mentor, please propose your project now here: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 It's very important to write your proposal as soon as possible to attract the best students. If you have any questions, please contact me immediately. If you happen to be in Sydney, come and have a chat with me directly. Happy coding, David

3 3

Regarding project idea for GSOC 2019
by Syed Souban 04 Mar '19

04 Mar '19

Hi guys! I am a machine learning enthusiast looking forward to work in implementing some machine learning algorithms in c++ as a gsoc 2019 project. I know that a similar project has been done last year. So in a way I want to extend to that idea. I needed some suggestions and or pointers on which algorithms are feasible to implement. Regards, Souban

2 1

(no subject)
by Roopkatha Samanta 04 Mar '19

04 Mar '19

I want to contribute to boost C++-Python integration project for my GSoC 2019 project.

1 0

[Boost.Intrusive]
by PREET THAKKAR 03 Mar '19

03 Mar '19

I am a 2nd year computer science student. I want to contribute to Boost.Intrusive as part of GSoC '19. I have some ideas to enhance Boost.Intrusive and also add more features to previous year's project in Intrusive. I am new to Boost. Any help regarding getting started with the library would be appreciated. Regards, Preet Thakkar

2 1

Re: [boost] Review request for variant2, review manager wanted
by Peter Dimov 03 Mar '19

03 Mar '19

> If anyone would like to step forward to manage the review, please do. Michael Caisse was the first to graciously offer his services (via Slack) and I'll be glad to have him manage the review. Thanks to Niall who also volunteered. :-) With respect to Niall's request for compile time and run time measurements, I've added a benchmark https://github.com/pdimov/variant2/blob/develop/benchmark/benchmark1.cpp and the results from compiling and running it on my machine are at https://github.com/pdimov/variant2/blob/develop/benchmark/benchmark1.md This is not a cherry-picked example that makes variant2 look good, so it loses to std::variant here and there. :-)

7 13

Runtime code generation
by VIKRAM LODHI 03 Mar '19

03 Mar '19

I am trying to write a grammar based code but can't seems to find starting point. Is there anything I should go through first. Grammar based . All the functions are written in string formats by user and parsed into binary at runtime and are able to use that function.

1 0

[release][multi_index] Permission to merge to master
by Joaquin M López Muñoz 03 Mar '19

03 Mar '19

I'm asking permission to merge the following fairly trivial changes to master: https://github.com/boostorg/multi_index/compare/bbb915bd344463ba767aebe7988… Travis and AppVeyor tests are passing. BTW, the conditions for allowed commits at this release stage ("closed for major changes") are not clear to me. Do I really need to ask for permission if the change (as is this case) is deemed minor? Joaquín M López Muñoz

2 4

Re: [boost] [Boost-testing] Running regression tests for msvc-14.2 (preview)
by Tom Kent 02 Mar '19

02 Mar '19

On Tue, Feb 26, 2019 at 7:13 AM Mateusz Loskot via Boost-Testing < boost-testing(a)lists.boost.org> wrote: > On Tue, 26 Feb 2019 at 14:02, Tom Kent via Boost-Testing > <boost-testing(a)lists.boost.org> wrote: > > I was hoping to start running regression tests for the upcoming Visual > Studio 2019 (toolset 14.2) and got stumped by an issue. > > I've set a user-config.jam: > > using msvc : 14.2 ; > > Is this toolset even supported? > > As I explained in > https://lists.boost.org/Archives/boost/2019/02/245143.php, > I had to 'fake' it as 14.1 in project-config.jam: > > using msvc : 14.1 : "C:\\Program Files (x86)\\Microsoft Visual > > Studio\\2019\\Preview\\VC\\Tools\\MSVC\\14.20.27323\\bin\\HostX64\\x64\\cl.exe" > I was able to get the regression tests to run using this workaround in user-config.jam. Here's what the config_info is: https://www.boost.org/development/tests/develop/developer/output/teeks99-te… I'm disappointed that we can't have general support for future versions of msvc. We don't seem to have this problem with pre-release versions of GCC/Clang. https://www.boost.org/development/tests/develop/developer/output/teeks99-02… Tom

3 5

Gsoc 2019 Boost.GIL project
by fady faragallah 02 Mar '19

02 Mar '19

Hi,I am fady faragallah 4th year student at faculty of computer engineering. I am interested in Boost.GIL and would like to contribute to the project. I have good experience in C++ programming and image processing algorithms and I am currently working on image processing and deep learning projects using convolutional neural networks. I need to know where I can deliver the competency test and how to contact the mentors. Thanks

1 0

Interested in working on Boost.GIL
by AvZ NaV 01 Mar '19

01 Mar '19

Hello, I am Arnav Tiwari, a sophomore year undergraduate student of IIT Kharagpur. I am interested in working on Boost.GIL. I have prior experience in image processing and C++ so I feel I will be able to pick up the project and get to work quickly. I would really appreciate it if someone can point me in the right direction to get started. I hope I'm not spamming the mailing list, apologies if that is the case. -- Regards, Arnav Tiwari

2 1

Re: [boost] [variant2] Need rationale for never-empty guarantee
by Nikita Kniazev 01 Mar '19

01 Mar '19

> This reply actually addresses my question: visitation on boost::variant2 is > faster than on std::variant because it does not have to account for the > valueless state. I would not expect perfomance differences on CPUs with branch predictor or if visitation translated into jump table (variant uses switch for this?). > For example, resizing a std::vector implements the strong guarantee that > state will be restored to before the resize if an exception is thrown in > the middle of the resize. Probably one should use different container type if a data types move/copy can throw. There even a vector implementation that will not copy/move on resize https://www.youtube.com/watch?v=Ke1mJiGO-pU (for CPU with virtual memory).

1 0

[appveyor] basic question
by Raffi Enficiaud 01 Mar '19

01 Mar '19

Hi Boost, Can somebody explain me like I am 5 what I need to do in order to activate Appveyor builds for boost.test? I am not admin of the repository. Thanks! Raffi

3 3

Review request for variant2, review manager wanted
by Peter Dimov 28 Feb '19

28 Feb '19

I'd like to request a formal Boost review for the Variant2 library, https://github.com/pdimov/variant2. Variant2 contains an implementation of a variant<T...> type that is an almost conforming std::variant, except it doesn't require C++17 and supports C++11 and above. It's also never valueless and has a few other extensions. The same library also contains an expected<T, E...> type, which is like the proposed std::expected<T, E>, but supports more than one error type. expected<> is not yet production-ready and has no test suite, but I will finish it if the library is accepted. The documentation for the variant<T...> class is at https://pdimov.github.io/variant2/index.html. If anyone would like to step forward to manage the review, please do.

10 15

Contributing to Boost.Algorithm
by Juho Lauri 28 Feb '19

28 Feb '19

Hello all, I'd be interested in contributing towards Boost.Algorithm - what's the appropriate way forward? Or perhaps this question has already been asked somewhere and I'd appreciate if you could point me to the right place. Thanks

1 0

A Unicode library?
by Can Topal 28 Feb '19

28 Feb '19

Hello everyone, Since I regularly work with Unicode text, I have started to design a Unicode library for handling UTF 8,16 and 32. The current support in C++ is still limited. Mainly I'm trying to implement a STL like support for file reading/writing, I/O operations and memory storage. So a user could read/write and process Unicode text like an ASCII string without knowing how the text is encoded. I thought people might have use for it. Even though libraries like ICU exist, they aren't beginner friendly and I couldn't find one with decent support for I/O. Is there demand for this? And if so do you guys have any suggestions? Thank you. - Onur

4 3

[GSOC19] [GIL]Image processing algorithms
by Shardul Parab 27 Feb '19

27 Feb '19

Hi! I am Shardul Parab, a computer science student from the Birla Institute of Technology and Science, Pilani. I am highly interested in contributing to Boost via GSoC 2019 and would love to contribute to the GIL library(as per the project idea listed). I believe that I have good practical experience of image processing techniques and if given the opportunity would be a great learning opportunity too. I have a decent experience with the library and would like to ask as to whether there is any particular task that I could begin with for the project and begin contributing from now itself under the guidance of a mentor. Thanking you, Regards. Shardul Parab

2 1

[GSOC2019][uBLAS] Linear and Multilinear Algebra with Matrix and Tensor Computations
by Ashar 27 Feb '19

27 Feb '19

Hi, I am Ashar Khan, a Second Year Computer Science Student from India. I would like to work with boost for Summer of Code 2019 and improve on the existing *boost.uBLAS *library. I have completed the Programming Competency test of uBLAS and find myself perfect for the task. I am looking forward to a mentor who can help me in the later parts of the project. I request any Potential mentor of uBLAS (David Bellot, Stefan Seefeld, and Sem Bassoy) to help me start my work. You can check my programming test on the following link here <https://github.com/coder3101/gsoc19-boost-test> Any Suggestions and opinions on the test are welcomed. Sorry if I did wrong by open-sourcing my test. I did not find any specific instructions as to how to submit the test. Looking forward to hearing from you soon. Thanks and Regards Ashar

2 1

Help regarding GSoC '19
by VIVEK MODI 27 Feb '19

27 Feb '19

Hey, I hope I am in the right mailing list. I am Vivek here. I am interested in working in the project Boost generic image library (project 1) listed by mentor Stefan Seefeld. If anyone can guide how to proceed further regarding the programming competency test and contributing to the project it would be of great help. -- Regards - Vivek Modi BTech(Information Technology) NIT Durgapur INDIA

2 1

[gsoc2019][astronomy] Program competency test
by rittik verma 27 Feb '19

27 Feb '19

Hello, I was reading through the competency test for boost astronomy and was struck by a question, should each coordinate has its own unit, for example, x - length, y - time, z-force? or just one unit for all coordinates? Thank you

2 1

clang-win clang-cl.exe on Windows 10 - is it time to add clang-win to the Boost test matrix?
by Paul A. Bristow 27 Feb '19

27 Feb '19

Confirming the work of others (pdimov and degski et al), I am now getting good results using clang-win (Clang 8.0.0 rc using GCC provided by Mingw64) on Windows 10. (Clang 8.0.0 should be finally released very soon now). Working the develop branch (fully up-to-date), I can run the Boost.Math examples and tests, and build the a set of most libraries (4 versions of most, for example) 27-Feb-19 14:32 15,872 boost_atomic-clangw8-mt-d-x64-1_70.dll 27-Feb-19 14:32 2,442 boost_atomic-clangw8-mt-d-x64-1_70.lib 27-Feb-19 14:32 9,728 boost_atomic-clangw8-mt-x64-1_70.dll 27-Feb-19 14:32 2,420 boost_atomic-clangw8-mt-x64-1_70.lib (but there are some failures to compile or to link). Examples in Addendum below: My user-config.jam contains using clang-win : # Clang Version. 8.0.0 : # Location of Clang compiler .exe file(s). Must use clang-cl driver, not clang++.exe # Copied path is "C:\LLVM\clang-700\LLVM\bin\clang-cl.exe" "C:/LLVM/clang-800/LLVM/bin/clang-cl.exe" -fuse-ld=lld # Use lld linker https://lld.llvm.org/, not clang++. # : # Options. <cxxflags>-v # Verbose output for testing only. ? --verbose does not work for clang? # <define>BOOST_CONFIG_SUPPRESS_OUTDATED_MESSAGE # <compileflags>-m64 Use address-model=64 on command line. <compatibility>vc14 # MS version compatibility. <cxxflags>-fmsc-version=1915 <cxxflags>-fms-compatibility <cxxflags>-fno-delayed-template-parsing #https://clang.llvm.org/docs/CommandGuide/clang.html#cmdoption-s # options are -flto, -flto=full, -flto=thin, -emit-llvm # Generate output files in LLVM formats, suitable for link time optimization. # The default for -flto is "full", in which the LLVM bitcode is suitable for monolithic Link Time Optimization (LTO), # where the linker merges all such modules into a single combined module for optimization. # With "thin", ThinLTO compilation is invoked instead. <cxxflags>-flto=thin # MS clang-cl compatibility settings: <cxxflags>"/std:c++17" # Must be c++17, not earlier. <cxxflags>"/Zc:forScope" <cxxflags>"/Zc:wchar_t" <cxxflags>"/EHsc" # exception handling # https://docs.microsoft.com/en-us/cpp/build/reference/eh-exception-handling-… # (/EHsc), catches C++ exceptions only and tells the compiler to assume that # functions declared as extern "C" never throw a C++ exception. <cxxflags>"/Zc:inline" <cxxflags>"/Gd" <cxxflags>"/diagnostics:classic" # Clang flags: # https://clang.llvm.org/docs/ClangCommandLineReference.html#compilation-flags # <cxxflags>-std=c++17 - already declared as a MS option. <cxxflags>-Wno-deprecated <cxxflags>-Wno-delete-non-virtual-dtor # <cxxflags>-fmacro-backtrace-limit=0 # <cxxflags>-Wno-invalid-token-paste <cxxflags>-Wno-language-extension-token <cxxflags>-Wno-microsoft-enum-value <cxxflags>-Wno-literal-range <cxxflags>-Wno-unknown-pragmas <cxxflags>-Wno-unused-variable <cxxflags>-Wno-microsoft-enum-value # <cxxflags>-Wno-invalid-constexpr # Need to stop reporting an error in Boost.System? <cxxflags>-Wno-unknown-argument <cxxflags>-Wno-unknown-pragmas <cxxflags>-Wno-macro-redefined <cxxflags>-Wno-unused-variable <cxxflags>-Wno-mismatched-tags <cxxflags>-Wno-deprecated-declarations <define>_CRT_SECURE_NO_DEPRECATE <define>_CRT_SECURE_NO_WARNINGS # Not all these may be needed to get a mostly warning-free build. ... My build command is \modular-boost>b2 -j4 toolset=clang-win-8.0.0 address-model=64 architecture=x86 --libdir=I:/modular-boost/lib --build-type=complete --without=mpi --without=python install 1>../boost_clang-win-8.0.0_64_config_27-Feb-19_1507.log I wonder if this means that it is time to add clang-win-8 configuration to the Boost Test summary at https://www.boost.org/development/tests/develop/developer/summary.html ? Paul PS What I have failed to get working is __float128 which works using GCC, but even after a patch enabling Clang in multiprecision's config and ensuring that quadmath.h is visible to the Clang compiler. It reports "not supported" :-( I have enquired if any progress can be made on making this work. Addendum - problem examples: ======================== LLVM ERROR: Associative COMDAT symbol '??_7codecvt_error_cat@?A0x15DB13AB@@6B@' does not exist. lld-link: error: undefined symbol: __imp_CryptGenRandom >>> referenced by I:\modular-boost\libs\random\src\random_device.cpp:121 >>> lto.tmp:("public: unsigned int __cdecl boost::random::random_device::impl::next(void)" (?next@impl@random_device@random@boost@@QEAAIXZ)) clang-cl: error: linker command failed with exit code 1 (use -v to see invocation) "C:/LLVM/clang-800/LLVM/bin/clang-cl.exe" "-fuse-ld=lld" -m64 /link /incremental:no /DLL /DEBUG /subsystem:console /out:"bin.v2\libs\random\build\clang-win-8.0.0\debug\address-model-64\threading-multi\boost_random-clangw8-mt-d-x64-1_70.dll" /IMPLIB:"bin.v2\libs\random\build\clang-win-8.0.0\debug\address-model-64\threading-multi\boost_random-clangw8-mt-d-x64-1_70.lib" @"bin.v2\libs\random\build\clang-win-8.0.0\debug\address-model-64\threading-multi\boost_random-clangw8-mt-d-x64-1_70.dll.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% and most annoyingly, since Boost.Test is a key library, "I:\modular-boost\lib\boost_unit_test_framework-clangw8-mt-d-x64-1_70.dll" "I:\modular-boost\lib\boost_unit_test_framework-clangw8-mt-d-x64-1_70.lib" but no release variants :-( clang-win.link.dll bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.dll LLVM ERROR: Associative COMDAT symbol '??_7results_reporter_impl@?A0x22C2280D@results_reporter@unit_test@boost@@6B@' does not exist. clang-cl: error: linker command failed with exit code 1 (use -v to see invocation) "C:/LLVM/clang-800/LLVM/bin/clang-cl.exe" "-fuse-ld=lld" -m64 /link /incremental:no /DLL /subsystem:console /out:"bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70. dll" /IMPLIB:"bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_ 70.lib" @"bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.dll. rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% ...failed clang-win.link.dll bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.dll bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.lib... --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

1 0

Running regression tests for msvc-14.2 (preview)
by Tom Kent 27 Feb '19

27 Feb '19

I was hoping to start running regression tests for the upcoming Visual Studio 2019 (toolset 14.2) and got stumped by an issue. I've set a user-config.jam: using msvc : 14.2 ; using python : 2.7 # version : C:\\Python27-32\\python.exe # Interperter/path to dir : C:\\Python27-32\\include # includes : C:\\Python27-32\\libs # libs : <address-model>32 <address-model> # conditions ; using python : 2.7 # version : C:\\Python27-64\\python.exe # Interperter/path to dir : C:\\Python27-64\\include # includes : C:\\Python27-64\\libs # libs : <address-model>64 # conditions ; Then I ran the command, from a vs2019 developer command prompt: D:\tmp>C:\Python27-64\python.exe run.py --runner=teeks99-test02 --toolsets=msvc-14.2 --tag=develop The full build output (minus some repetitive git and mklink commands) can be found here: https://gist.github.com/teeks99/2d72382bf13569855dbdcd2e0850c1cf A couple notable parts... Bootstrap says it is using the vc7 toolset, which isn't installed D:\tmp\boost_bb\src\engine>build.bat could not find "vswhere" ### ### Using 'vc7' toolset. ### but succeeds anyway, probably because cl.exe is available in the path in the vs2019 command prompt. B2.exe is successfully created and seems to work. During... notice: [python-cfg] Configuring python... [snip] ImportError: No module named numpy but that is normal. Finally, at the end...the real issue: ...skipped <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <p..\..\bin\common\build\msvc-14.2\release\threading-multi>process_jam_log.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... common.mkdir D:\tmp\boost_root\bin.v2 if not exist "D:\tmp\boost_root\bin.v2\\" mkdir "D:\tmp\boost_root\bin.v2" common.mkdir D:\tmp\boost_root\bin.v2\libs if not exist "D:\tmp\boost_root\bin.v2\libs\\" mkdir "D:\tmp\boost_root\bin.v2\libs" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2 if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi" ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>codecvt_error_category.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>operations.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>path.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>path_traits.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>portability.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>unique_path.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>utf8_codecvt_facet.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>windows_file_codecvt.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>libboost_filesystem-vc142-mt-1_70.lib for lack of <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>codecvt_error_category.obj... ...skipped <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.exe for lack of <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.obj... ...skipped <pD:\tmp\boost_regression\stage\bin>process_jam_log.exe for lack of <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.exe... ...skipped 14 targets... ...updated 599 targets... # Searching for "process_jam_log.exe" in "D:\tmp\boost_regression\stage\bin"... Traceback (most recent call last): File "run.py", line 71, in <module> runner(root) File "D:\tmp\boost_regression_src\regression.py", line 286, in __init__ self.main() File "D:\tmp\boost_regression_src\regression.py", line 623, in main getattr(self,action_m)() File "D:\tmp\boost_regression_src\regression.py", line 580, in command_regression self.command_setup() File "D:\tmp\boost_regression_src\regression.py", line 351, in command_setup self.build_if_needed(self.process_jam_log,self.pjl_toolset) File "D:\tmp\boost_regression_src\regression.py", line 714, in build_if_needed tool[ 'build_path' ] = self.tool_path( tool ) File "D:\tmp\boost_regression_src\regression.py", line 739, in tool_path , '\n'.join( [ name_or_spec[ 'path' ], build_dir ] ) Exception: Cannot find "process_jam_log.exe" in any of the following locations: D:\tmp\boost_regression\stage\bin\process_jam_log.exe D:\tmp\boost_regression\stage\bin What is the msvc-setup.nup and where does it come from? Thanks, Tom

3 4

Building the Release Notes locally
by Vinnie Falco 27 Feb '19

27 Feb '19

Does anyone know how to build the release notes locally? I would like to know if they render correctly without going through an 8-hour Travis turnaround. The rumor mill says @Daniel James knows how to do it... Anyone?? Thanks

2 2

[Boost.astronomy]
by Viraj Sonaje 24 Feb '19

24 Feb '19

This is for the respective authority I am a 4th year engineering student. I want to contribute to Boost.astronomy library for GSOC 2019. I am familiar with the co-ordinate systems but I am new to boost.

2 1

Graph Algorithms
by Siddhartha Sen 24 Feb '19

24 Feb '19

Is there any interest in a library containing graph algorithms? Also, I am unable to find the list of maintainers of the respective libraries. Any information on that would be appreciated.

7 7

add serialization to circular_buffer
by Yuval Lifshitz 24 Feb '19

24 Feb '19

Dear Community,I have a PR [1] for supporting serialization of the circular_buffer. Main drive for this change, is my effort for adding serialization to boost accumulators [2] (some accumulators hold data internally in a circular buffer).The maintainers list [3] is not up to date regarding circular buffer, so, I'm not sure who the maintainer is (or if there is one). Would appreciate your help, so I can drive that to completion. Yuval Lifshitz [1] https://github.com/boostorg/circular_buffer/pull/25[2] https://github.com/boostorg/accumulators/pull/18 [3] https://github.com/boostorg/boost/blob/master/libs/maintainers.txt

1 0

BGL
by Siddhartha Sen 22 Feb '19

22 Feb '19

I looked up https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 . No project ideas have been added for BGL as of yet, it seems. I hope there is something in BGL in this years GSOC, as I am really passionate about graphs and graph algorithms. Also, will you be mentoring this year? If not, do you have any information on the potential mentors for this BGL project? Thanks.

2 1

Re: [boost] Graph Algorithms
by Siddhartha Sen 22 Feb '19

22 Feb '19

Thanks for the feedback! But what if I focus on C++14 then? Is that a good idea? On Fri, 22 Feb, 2019, 6:14 PM Vinnie Falco, <vinnie.falco(a)gmail.com> wrote: > On Fri, Feb 22, 2019 at 12:49 AM Siddhartha Sen > <siddhartha99.sen(a)gmail.com> wrote: > > From what I've read in the mailing lists, I think the demand has > shifted > > from C++11 to more modern versions, like C++14 and C++17. Anyways, > > thanks for the tip. Will you be mentoring this year? > > I will not be mentoring directly although I do offer advice on the mailing > list. > > People say they want C++14 and C++17 but I don't think its a good idea > to require those language versions in a library, because most people > are still on C++11. Have a look at the latest developer survey: > > <https://www.jetbrains.com/research/devecosystem-2018/cpp/> > > If a library requires C++17 then most C++ users will not be able to > use it. And this is bad for the library, because fewer users means > less testing, less feedback, less popularity, and in general this > makes the library not as good. > > In terms of the API (interface) of a library, C++17 does not offer > much more than C++11 except for things like, avalability of > string_view, variant. But Boost has these things already (e.g. > boost::string_view, boost::variant) and they work in C++11. So there > is really no benefit to C++17 other than some improvements in the way > you can write the implementation. But that doesn't affect users > directly. > > In summary, by requiring C++17 most users will be unable to use the > code, and there will be very little benefit to C++17 users. > > Regards >

3 7

BGL
by Siddhartha Sen 22 Feb '19

22 Feb '19

I apologise. Actually, there was a suggestion in the boost mailing lists that there is a demand for this. Anyways, I am familiar with C++14 and a C++17 as well(a bit). Will you be mentoring this year? I have already read the documentation of LEMON and started using it as well. Please let me know what should I do next, or if there are any particular issues you would like me to work on. Thanks. Regards. Siddhartha.

2 1

BGL: Graph11
by Siddhartha Sen 22 Feb '19

22 Feb '19

Hi, I am SIddhartha Sen, a second year student in Information Science and Engineering. I hope to contribute to the BGL. I have heard that there is some interest in themodernization of BGL using modern C++11 concepts for improved performance. Being a GSOC 2019 aspirant, I was looking for a potential mentor in this domain to pair up with and get started on this project. Any help would be greatly appreciated. Thank You.

2 1

PR not merged
by Sreejith S 21 Feb '19

21 Feb '19

I have sent a PR[1]. Can I know why the PR is still not merged ? [1]:https://github.com/boostorg/graph/pull/158 -- Regards, Sreejith.S Amrita Vishwa Vidyapeetham FOSS@Amrita <http://amfoss.in> | Github <https://github.com/sreejithsankar55> | Blog <http://sreejithsankar.wordpress.com>

1 0

Re: [boost] [build] PROBLEM specifying libc++!!!!
by Nikita Kniazev 21 Feb '19

21 Feb '19

> Anyone know how to do this and have the will to make life easier for > poor overworked library maintainers? I have `b2 <stdlib>libc++` on CI for Spirit with https://github.com/boostorg/spirit/blob/develop/.travis.yml#L119-L121 When I tried to make a PR I stuck at the thing that I do not know how (or it is not possible) to format (free-)future value into some flags, i.e: > toolset.flags clang-linux.compile OPTIONS <stdlib> : -stdlib=[ value-of-feature <stdlib> ] ; > toolset.flags clang-linux.link OPTIONS <stdlib> : -stdlib=[ value-of-feature <stdlib> ] ; But since in the wild there are two possible options it might be ok to just hardcode them for now.

1 0

[GIL] Contribution to the library.
by Gaurav Hoskote 21 Feb '19

21 Feb '19

This is to inform the concerned authority that I am willing to participate in GSOC 2019 and wish to contribute to the GIL library. I am a final year student and have good understanding of operations like Thresholding, Morphology and various filters. I have an idea of how the library works and I wish to contribute to it under the guidance of a mentor.

2 1

Image Processing for [GIL] Boost.
by Gaurav Hoskote 21 Feb '19

21 Feb '19

The Boost GIL library lacks image processing header files for operations like thresholding, morphology etc. I intend to contribute to this library by proposing some header files that can be placed in this library. I have worked on image processing algorithms before and am familiar with all the concepts.I wish to work under the mentorship of Stefan Seefeld who posted this project on github for GSOC 2019. I have attached a proposal pdf file (gilpro.pdf) to this email which gives details about my work and how the project will be implemented along with goals and milestones to be achieved. Also, for competency test I have attached a sample header file (threshold.h) which gives a basic idea of what I wish to implement for my project. Feedback would be appreciated. Regards, Gaurav Hoskote.

1 0

[build] PROBLEM specifying libc++!!!!
by Vinnie Falco 21 Feb '19

21 Feb '19

This is hard to teach, hard to remember, and error prone: script: b2 -j3 libs/beast/test toolset=clang cxxstd=11 cxxflags=-stdlib=libc++ linkflags=-stdlib=libc++ There's an issue to address it in a straightforward fashion: <https://github.com/boostorg/build/issues/287> Anyone know how to do this and have the will to make life easier for poor overworked library maintainers? Regards

1 0

[GSoC 2019] cpp_int Improvement
by Fenil Mehta 20 Feb '19

20 Feb '19

Hi, Integers with the capability to store large numbers has always been a requirement in C++ which has successfully been implemented by boost/multiprecision/cpp_int. Other languages such as Python and Java also supports such integer datatypes. I performed a speed test for C++ and python integers. While comparing speed of cpp_int and python int, I noticed that even though C++ source program was compiled with -O2 and -O3 flags, cpp_int was slow as compared for python int for multiplication and left-shift operations. The time taken for multiplication was: 1) cpp_int = 17.06 seconds 2) python int = 8.39 seconds I used the attached files to perform the testing on Linux. The execution time was measured using the time command. I would like to optimize this library. Being a GSoC aspirant, I was looking to pair up with a potential mentor in this domain who could guide me. Any feedback would be appreciated. Regards, Fenil Mehta

2 1

[asio] windows compilation error
by Vinnie Falco 19 Feb '19

19 Feb '19

This program fails to compile under msvc.latest: #include <boost/asio.hpp> int main { return 0; } This program does compile: #define BOOST_ASIO_DISABLE_WINDOWS_RANDOM_ACCESS_HANDLE 1 #define BOOST_ASIO_DISABLE_WINDOWS_STREAM_HANDLE 1 #include <boost/asio.hpp> int main { return 0; } Thanks

1 0

Integer sorting
by Fenil Mehta 19 Feb '19

19 Feb '19

I have written a sorting algorithm which is way faster than std::sort for all array size. The link is as follows: https://github.com/fenilgmehta/Fastest-Integer-Sort Some guidance would be appreciated on how to improve the project structure and the steps to get it included in boost. Regards, Fenil Mehta

11 24

Regression tests broken
by Tom Kent 19 Feb '19

19 Feb '19

All- Sometime around 7pm yesterday (2-17) a commit went in (master and develop?, regression scripts?) that broke all my regression runners (linux and windows). I haven't had a ton of time to dig in, but the end of the results look like this: notice: using boost library auto_config <layout>system ../libs/contract/test/Jamfile.v2:417: Unescaped special character in argument <define>BOOST_CONTRACT_ON_MISSING_CHECK_DECL="{ throw err(); }" notice: [libjpeg] Using pre-installed library notice: [libjpeg] Condition notice: [zlib] zlib is already configured notice: [libpng] Using pre-installed library notice: [libpng] Condition notice: [libtiff] Using pre-installed library notice: [libtiff] Condition /var/boost/run/boost_bb/src/build/feature.jam:447: in extend-feature from module feature error: coverage is already associated with the "<variant>" feature /var/boost/run/boost_bb/src/build/feature.jam:624: in feature.extend from module feature /var/boost/run/boost_bb/src/tools/features/variant-feature.jam:79: in variant from module variant-feature ../libs/histogram/Jamfile:15: in modules.load from module Jamfile</var/boost/run/boost_root/libs/histogram> /var/boost/run/boost_bb/src/build/project.jam:372: in load-jamfile from module project /var/boost/run/boost_bb/src/build/project.jam:64: in load from module project /var/boost/run/boost_bb/src/build/project.jam:109: in load-parent from module project /var/boost/run/boost_bb/src/build/project.jam:513: in initialize from module project /var/boost/run/boost_bb/src/build/project.jam:348: in load-jamfile from module project /var/boost/run/boost_bb/src/build/project.jam:64: in load from module project /var/boost/run/boost_bb/src/build/project.jam:142: in project.find from module project Jamfile.v2:122: in run-tests from module Jamfile</var/boost/run/boost_root/status> Jamfile.v2:196: in modules.load from module Jamfile</var/boost/run/boost_root/status> /var/boost/run/boost_bb/src/build/project.jam:372: in load-jamfile from module project /var/boost/run/boost_bb/src/build/project.jam:64: in load from module project /var/boost/run/boost_bb/src/build/project.jam:142: in project.find from module project /var/boost/run/boost_bb/src/build-system.jam:618: in load from module build-system /var/boost/run/boost_bb/src/kernel/modules.jam:295: in import from module modules /var/boost/run/boost_bb/src/kernel/bootstrap.jam:139: in boost-build from module /var/boost/run/boost_root/boost-build.jam:17: in module scope from module Any thoughts? Tom

6 6

[Asio][ssl] develop broken
by Damian Jarek 18 Feb '19

18 Feb '19

After the changes today (introduced in https://github.com/boostorg/asio/commit/0568d3bf0b492887c6c48d05f5492a782da… ) an overload of async_handshake( https://github.com/boostorg/asio/blob/develop/include/boost/asio/ssl/stream…) fails to compile because of the signature mismatch in async_result. This is a show-stopper, because it breaks quite a bit of code in Beast.

2 1

Searching and Sorting algorithms
by Siddhartha Sen 18 Feb '19

18 Feb '19

Sorry for the typo. I meant "generic", not genetic. Anyways, I went through the non-mutating algorithms section and can't think of anything to possibly add. I had three questions though: 1. Is there any interest in libraries aimed at solving any small but particular problem, for example, say tower of hanoi in minimum possible time? 2. For any existing algorithm, if we add some features would it be useful? For example, as far as I know, binary search returns true if an element is found and false, if not. What if we add the elements position if found? Does not change complexity, but makes it better to use,doesn't it? 3. I want to contribute to the sorting algorithms library as well, any idea where to start? Is there any scope for improvement of any existing algorithms? Also, if we want to add any entirely new algorithms of our own, any suggestions where to start? I am working on an algorithm currently and was hoping to propose it to the boost libraries. Sorry if my post got too lengthy. Any help would be appreciated. Thank You.

2 1

[Asio] develop broken on Windows
by Vinnie Falco 18 Feb '19

18 Feb '19

This program fails to compile on Windows: #include <boost/asio.hpp> int main() { return 0; } Regards

1 0

Searching Algorithm
by Siddhartha Sen 17 Feb '19

17 Feb '19

Looking to contribute to the sorting library under algorithms. Any mentors available? Also, is their any interest in searching algorithms? I looked up the boost libraries but couldn't find any. Are there any mentors available? I want to make a searching library which will be genetic in nature and applicable for all data types. Any guidance would be appreciated. Thanks. Siddhartha

2 1

building, debugging and contributing to an individual boost library
by Sean Farrow 17 Feb '19

17 Feb '19

Hi, Once I have forked an individual boost library, what is the best way of building the library with b2? How are dependencies on other libraries handled? Secondly, how can I build, run and debug tests using visual studio? Any help appreciated. Kind regards Sean.

6 7

New user need guidance.
by SHREYANS JAIN 17 Feb '19

17 Feb '19

Hi I am Shreyans Jain. I am new to opensource programming, can anyone guide me how to start contributing here. Thank You

1 0

Re: [boost] Mail list is poorly indexed by Google
by Nikita Kniazev 15 Feb '19

15 Feb '19

> > Indeed! Google stopped indexing January 2017. Strange, I linked mid-December thread, if crawlers stopped indexing in January there was more than two weeks to index it, is not it?

3 3

String Algorithms
by Siddhartha Sen 14 Feb '19

14 Feb '19

Hi, I would like to contribute to the string algorithms library for GSOC 2019. Are there any potential mentors to pair up with? I am also interested in algorithms in general, especially sorting and searching libraries. Is there any scope for contribution there as well? Any answers would be appreciated

1 0

Mail list is poorly indexed by Google
by Nikita Kniazev 13 Feb '19

13 Feb '19

I was going to find the https://lists.boost.org/Archives/boost/2018/12/244648.php thread, but it did not worked with Google (looked all the pages <https://www.google.com/search?q=dropping+support+for+msvc+9+site%3Alists.bo…>), while DuckDuckGo shows it as the first link <https://ddg.gg/?q=dropping+support+for+msvc+9+site%3Alists.boost.org>. Can webmasters look into this with the Google's Search Console <https://search.google.com/search-console/about>? Or it is a policy to supplant the all-embracing Google? :-)

2 1

Regarding Boost.Real
by Sreejith S 13 Feb '19

13 Feb '19

Hi all I am Sreejith, a sophomore at Amrita University. I had gone through GSoC projects and I found Bringing Boost.Real to review-ready state interesting. As a beginner, I tried to understand the blog post of previous year's GSoC-18 project of the same. It seemed too difficult for me. Is it ok to work on it without any experience? -- Regards, Sreejith.S Amrita Vishwa Vidyapeetham FOSS@Amrita <http://amfoss.in> | Github <https://github.com/sreejithsankar55> | Blog <http://sreejithsankar.wordpress.com>

1 0

[gsoc2019][astronomy]
by rittik verma 12 Feb '19

12 Feb '19

Hello everyone, I am Rittik Verma, a third year Computer Science student. I am looking forward to contributing to the Astronomy library for GSoC 2019. I have studied the repository and would like to add the expected features to the library. I was wondering if the potential mentor has already paired up with a student or the position is still available? My projects: https://github.com/codectile Thank you

4 3

GSoC 2019
by Shourya IIT B 12 Feb '19

12 Feb '19

Respected Sir, I am Parashuram Shourya from India. Currently, I am doing my Master’s in Geoinformatics from Centre of Studies in Resources Engineering(CSRE), Indian Institute of Technology Bombay(IITB). I have a Bachelor's degree in Computer Science and Engineering. Currently, I am learning Machine Learning and High-Performance Computing. I have vast programming experience in C, C++, Python I would love to contribute to Boost C++ Libraries in the upcoming Google Summer of Code 2019. I would be very grateful to get any directions to start with so that I can pursue and participate in GSoC 2019 with your organization.

1 0

[GSOC 19] Programming competency test for ublas
by Amit Singh 10 Feb '19

10 Feb '19

Hi, My name is Amit Singh and I’m interested in machine learning lib for ublas as already provided in my idea list in mailing list. I have completed my programming competency test for ublas and wanted to know where to submit it.

1 0

An interest in a neural net library?
by Sergei Marchenko 09 Feb '19

09 Feb '19

Hi everyone. I would like to get your opinion if there is any interest for a library that implements simple neural networks trained via backpropagation. The main idea is to define the configuration of a feed-forward multi-layer network via template parameters, and also provide implementations for a couple of well-known variations of networks (i.e. convolutional, sampling, network ensemble etc). // Define a network ensemble with two networks with the same input and output size, // but different number of neuron layers and different number of neurons in each layer. typedef neural_network<100, 50, 10> network_1; typedef neural_network<100, 70, 20, 10> network_2; auto network = ensemble(network_1(), network_2()); // Train the network from a training set. // item.input is a 100-element input vector. // item.target is the 10-element desired output vector. for (auto item : training_set) network.train(item.input, item.target, learning_rate); // Feed some input data into the network to get the result. auto result = network.process(input); This code on github that my nephew and myself wrote a couple of years ago can be used as a more detailed illustration for the idea: https://github.com/nsokolnikov/mathlib/blob/master/src/neuralnet.h Also, this github repo has two sample projects that illustrate usage of the library. First sample trains a simple network with a simulated activity pattern and then uses the network to classify more simulated load as low, medium, or high: https://github.com/nsokolnikov/mathlib/tree/master/samples/NeuralNetwork Second sample trains a network on a part of MNIST data set of hand-written digits, and then uses the network to recognize the remaining part of the MNIST data set: https://github.com/nsokolnikov/mathlib/tree/master/samples/TextRecognition Thank you, Serguei Martchenko

1 0

Sorting and Searching Algorithms Library
by Siddhartha Sen 09 Feb '19

09 Feb '19

Actually, I am interested equally in both searching and sorting algorithms. In sorting algorithms, I am actually trying recursive implementations of all the known algorithms myself, to see if somehow I can find any variations or maybe even an whole new algorithm which can give a better time complexity. As far as searching algorithm goes, my knowledge is unfortunately limited to only binary search and linear search and DFS and BFS if graphs are counted . However I am working on patterns in numbers to try and create a generic searching algorithm for integer arrays and strings. Apart from this, I am afraid I don't have a lot of idea and hence I am seeking guidance. Thanks On Sat, 9 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. building boost libraries with pdb files under windows > (Sean Farrow) > 2. Re: Boost Digest, Vol 5998, Issue 1 (Siddhartha Sen) > 3. Re: building boost libraries with pdb files under windows > (Daniela Engert) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 8 Feb 2019 12:05:58 +0000 > From: Sean Farrow <sean.farrow(a)seanfarrow.co.uk> > To: "boost(a)lists.boost.org" <boost(a)lists.boost.org> > Subject: [boost] building boost libraries with pdb files under windows > Message-ID: > < > DB6PR0501MB27593FBAC29B49059A752178C6690(a)DB6PR0501MB2759.eurprd05.prod.outlook.com > > > > Content-Type: text/plain; charset="us-ascii" > > Hi, > > Is there a way to build boost libraries with PDB files under visual C++ > 2017? > > Any help appreciated. > > Kind regards > Sean. > > > ------------------------------ > > Message: 2 > Date: Fri, 8 Feb 2019 22:32:18 +0530 > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > To: boost(a)lists.boost.org, phdcluster(a)gmail.com > Subject: Re: [boost] Boost Digest, Vol 5998, Issue 1 > Message-ID: > < > CA+iicpFdnd67wpP25MVjXtBxW5TFEkGb78XL-SK5RPosw_nMHQ(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Actually, I am interested equally in both searching and sorting algorithms. > In sorting algorithms, I am actually trying recursive implementations of > all the known algorithms myself, to see if somehow I can find any > variations or maybe even an whole new algorithm which can give a better > time complexity. As far as searching algorithm goes, my knowledge is > unfortunately limited to only binary search and linear search and DFS and > BFS if graphs are counted . However I am working on patterns in numbers to > try and create a generic searching algorithm for integer arrays and > strings. Apart from this, I am afraid I don't have a lot of idea and hence > I am seeking guidance. > Thanks > > On Fri, 8 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > > > Send Boost mailing list submissions to > > boost(a)lists.boost.org > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.boost.org/mailman/listinfo.cgi/boost > > or, via email, send a message with subject or body 'help' to > > boost-request(a)lists.boost.org > > > > You can reach the person managing the list at > > boost-owner(a)lists.boost.org > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of Boost digest..." > > > > > > The boost archives may be found at: > http://lists.boost.org/Archives/boost/ > > > > > > Today's Topics: > > > > 1. qxcalc(GSoC2019) (Ggh) > > 2. qxcalc(GSoC2019)-2 (Ggh) > > 3. Sorting Algorithms Library (Siddhartha Sen) > > 4. Re: Sorting Algorithms Library (phdcluster) > > 5. Re: Feedback desired for reflective enum library (David Sankel) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Thu, 07 Feb 2019 10:07:10 +0200 > > From: Ggh <ggh(a)multi.fi> > > To: boost(a)lists.boost.org > > Subject: [boost] qxcalc(GSoC2019) > > Message-ID: > > <20190207100710.Horde.VkEf1bfe3uAO1wELKmHKrul(a)webmail.multi.fi> > > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > > > > Hi all, > > Not sure if there is interest, but some years ago I coded a > > parser/lexer with flex and yacc to do math. > > > > The project is online here > > "http://qxcalc.sourceforge.net/" > > > > Greg > > > > > > > > ------------------------------ > > > > Message: 2 > > Date: Thu, 07 Feb 2019 11:01:16 +0200 > > From: Ggh <ggh(a)multi.fi> > > To: boost(a)lists.boost.org > > Subject: [boost] qxcalc(GSoC2019)-2 > > Message-ID: > > <20190207110116.Horde.VeAEqWouVIYk0-9NMfOsi9P(a)webmail.multi.fi> > > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > > Some links on my page(these pages are not always online): > > > > http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html > > http://www.multi.fi/~ghaga/qxcalc/ > > http://www.multi.fi/~ghaga/qxcalc/download.php > > > > Ty, > > Greg > > > > > > > > > > ------------------------------ > > > > Message: 3 > > Date: Fri, 8 Feb 2019 01:43:42 +0530 > > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > > To: boost(a)lists.boost.org > > Subject: [boost] Sorting Algorithms Library > > Message-ID: > > <CA+iicpGMx+zroF= > > RhE7AtAqJiN4Rw6Fz3hvPnvKmKP6+htKQJg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > Hi, > > This is Siddhartha Sen, a student of Information Science and > > Engineering. I am proficient in C++ and am particularly interested in > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with > a > > potential mentor in this domain, who could give me some much needed > > guidance. > > Thank You > > > > > > ------------------------------ > > > > Message: 4 > > Date: Thu, 7 Feb 2019 17:30:36 -0500 > > From: phdcluster <phdcluster(a)gmail.com> > > To: boost(a)lists.boost.org > > Cc: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > > Subject: Re: [boost] Sorting Algorithms Library > > Message-ID: > > < > > CAKYCxYFSbMoxJf4ycjgMxLQSQq9ddkuZUa1BF7bMfBOhntWO1Q(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > What particular sorting algorithm you are interested in? Or what > algorithms > > you have in mind? > > > > Thanks, > > > > Wen > > > > On Thu, Feb 7, 2019 at 3:50 PM Siddhartha Sen via Boost < > > boost(a)lists.boost.org> wrote: > > > > > Hi, > > > This is Siddhartha Sen, a student of Information Science and > > > Engineering. I am proficient in C++ and am particularly interested in > > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up > with > > a > > > potential mentor in this domain, who could give me some much needed > > > guidance. > > > Thank You > > > > > > _______________________________________________ > > > Unsubscribe & other changes: > > > <http://lists.boost.org/mailman/listinfo.cgi/boost> > > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > > > > ------------------------------ > > > > Message: 5 > > Date: Thu, 7 Feb 2019 19:39:11 -0500 > > From: David Sankel <camior(a)gmail.com> > > To: Nir Friedman <quicknir(a)gmail.com> > > Cc: Boost <boost(a)lists.boost.org> > > Subject: Re: [boost] Feedback desired for reflective enum library > > Message-ID: > > < > > CAFYdOOLxMqup9-0Vub+UNJGgpvaqTGL0mWr1d1txuq4mstMJGg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Tue, Feb 5, 2019, 2:00 PM Nir Friedman <quicknir(a)gmail.com> wrote: > > > > > Sure, I'm open to such a thing. Although, I feel like there may be > > caveats > > > to that (i.e. whether the reflection TS interface is easy to use, > whether > > > it's easy to emulate library-only, how likely it is to continue > changing, > > > etc). Do you have a link to a paper that shows what the latest in the > > > reflection TS for enums looks like? > > > > > > > http://cplusplus.github.io/reflection-ts/draft.pdf > > > > > > > > > > > ------------------------------ > > > > Subject: Digest Footer > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > ------------------------------ > > > > End of Boost Digest, Vol 5998, Issue 1 > > ************************************** > > > > > ------------------------------ > > Message: 3 > Date: Fri, 8 Feb 2019 19:16:44 +0100 > From: Daniela Engert <dani(a)ngrt.de> > To: boost(a)lists.boost.org > Subject: Re: [boost] building boost libraries with pdb files under > windows > Message-ID: <9a268d74-c868-f79b-2f2e-52f693482356(a)ngrt.de> > Content-Type: text/plain; charset=iso-8859-15 > > Hi Sean! > > Am 08.02.2019 um 13:05 schrieb Sean Farrow via Boost: > > > Is there a way to build boost libraries with PDB files under visual C++ > 2017? > > Well, I am generating PDBs for a couple of years now using a slightly > modified msvc.jam (see > https://github.com/DanielaE/boost.build/commits/vc) Unfortunatly, this > is just a hack that happens to work well enough for my use-case and > requires an additional step to collect the PDBs from the build tree to > the stage directory using some script. Putting more effort into this > isn't economical for at most three distribution build per year. > > Ciao, > Dani > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 5999, Issue 1 > ************************************** >

1 0

building boost libraries with pdb files under windows
by Sean Farrow 08 Feb '19

08 Feb '19

Hi, Is there a way to build boost libraries with PDB files under visual C++ 2017? Any help appreciated. Kind regards Sean.

2 1

Re: [boost] Boost Digest, Vol 5998, Issue 1
by Siddhartha Sen 08 Feb '19

08 Feb '19

Actually, I am interested equally in both searching and sorting algorithms. In sorting algorithms, I am actually trying recursive implementations of all the known algorithms myself, to see if somehow I can find any variations or maybe even an whole new algorithm which can give a better time complexity. As far as searching algorithm goes, my knowledge is unfortunately limited to only binary search and linear search and DFS and BFS if graphs are counted . However I am working on patterns in numbers to try and create a generic searching algorithm for integer arrays and strings. Apart from this, I am afraid I don't have a lot of idea and hence I am seeking guidance. Thanks On Fri, 8 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. qxcalc(GSoC2019) (Ggh) > 2. qxcalc(GSoC2019)-2 (Ggh) > 3. Sorting Algorithms Library (Siddhartha Sen) > 4. Re: Sorting Algorithms Library (phdcluster) > 5. Re: Feedback desired for reflective enum library (David Sankel) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 07 Feb 2019 10:07:10 +0200 > From: Ggh <ggh(a)multi.fi> > To: boost(a)lists.boost.org > Subject: [boost] qxcalc(GSoC2019) > Message-ID: > <20190207100710.Horde.VkEf1bfe3uAO1wELKmHKrul(a)webmail.multi.fi> > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > Hi all, > Not sure if there is interest, but some years ago I coded a > parser/lexer with flex and yacc to do math. > > The project is online here > "http://qxcalc.sourceforge.net/" > > Greg > > > > ------------------------------ > > Message: 2 > Date: Thu, 07 Feb 2019 11:01:16 +0200 > From: Ggh <ggh(a)multi.fi> > To: boost(a)lists.boost.org > Subject: [boost] qxcalc(GSoC2019)-2 > Message-ID: > <20190207110116.Horde.VeAEqWouVIYk0-9NMfOsi9P(a)webmail.multi.fi> > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > Some links on my page(these pages are not always online): > > http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html > http://www.multi.fi/~ghaga/qxcalc/ > http://www.multi.fi/~ghaga/qxcalc/download.php > > Ty, > Greg > > > > > ------------------------------ > > Message: 3 > Date: Fri, 8 Feb 2019 01:43:42 +0530 > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > To: boost(a)lists.boost.org > Subject: [boost] Sorting Algorithms Library > Message-ID: > <CA+iicpGMx+zroF= > RhE7AtAqJiN4Rw6Fz3hvPnvKmKP6+htKQJg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hi, > This is Siddhartha Sen, a student of Information Science and > Engineering. I am proficient in C++ and am particularly interested in > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with a > potential mentor in this domain, who could give me some much needed > guidance. > Thank You > > > ------------------------------ > > Message: 4 > Date: Thu, 7 Feb 2019 17:30:36 -0500 > From: phdcluster <phdcluster(a)gmail.com> > To: boost(a)lists.boost.org > Cc: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > Subject: Re: [boost] Sorting Algorithms Library > Message-ID: > < > CAKYCxYFSbMoxJf4ycjgMxLQSQq9ddkuZUa1BF7bMfBOhntWO1Q(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > What particular sorting algorithm you are interested in? Or what algorithms > you have in mind? > > Thanks, > > Wen > > On Thu, Feb 7, 2019 at 3:50 PM Siddhartha Sen via Boost < > boost(a)lists.boost.org> wrote: > > > Hi, > > This is Siddhartha Sen, a student of Information Science and > > Engineering. I am proficient in C++ and am particularly interested in > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with > a > > potential mentor in this domain, who could give me some much needed > > guidance. > > Thank You > > > > _______________________________________________ > > Unsubscribe & other changes: > > <http://lists.boost.org/mailman/listinfo.cgi/boost> > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > ------------------------------ > > Message: 5 > Date: Thu, 7 Feb 2019 19:39:11 -0500 > From: David Sankel <camior(a)gmail.com> > To: Nir Friedman <quicknir(a)gmail.com> > Cc: Boost <boost(a)lists.boost.org> > Subject: Re: [boost] Feedback desired for reflective enum library > Message-ID: > < > CAFYdOOLxMqup9-0Vub+UNJGgpvaqTGL0mWr1d1txuq4mstMJGg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Tue, Feb 5, 2019, 2:00 PM Nir Friedman <quicknir(a)gmail.com> wrote: > > > Sure, I'm open to such a thing. Although, I feel like there may be > caveats > > to that (i.e. whether the reflection TS interface is easy to use, whether > > it's easy to emulate library-only, how likely it is to continue changing, > > etc). Do you have a link to a paper that shows what the latest in the > > reflection TS for enums looks like? > > > > http://cplusplus.github.io/reflection-ts/draft.pdf > > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 5998, Issue 1 > ************************************** >

1 0

Feedback desired for reflective enum library
by Nir Friedman 08 Feb '19

08 Feb '19

Hey, I have a reflective enum library available here: https://github.com/quicknir/wise_enum. I've been working on this on and off for a couple of months. I've added features, dealt with various issues, added docs, expanded support through 11-17 and as idiomatically as possible. Overall I think the library is in nice shape (lacks unit tests though, though I do already have a boost license for the code). I feel like a reflective enum is just a very standard requirement in pretty much every codebase I've ever worked on. Simply to be able to reasonably log enums already makes it mandatory. It's also invaluable in configuration, error message alerting, and many other places. There is nothing for this in boost and actually there isn't really much of a standard, standalone solution anyway. The closest is Better Enums ( http://aantron.github.io/better-enums/) but this has some major issues (it doesn't actually create enums but rather enum-like classes, it targets 03). So I think a library like this is needed and my implementation ticks off the major requirements. Feedback on the overall design, any issues, any key features it fails to meet, would be very useful. The library itself is very small and simple so its easy to review. Once it seems like there's some consensus on the core design I'm willing to do the work involved getting it into boost (naming conventions/requirements, directory structure, tests, boost-style docs, etc). Note I'm not on the boost mailing list so please respond directly to this email so I can see! Cheers, Nir

3 4

Sorting Algorithms Library
by Siddhartha Sen 07 Feb '19

07 Feb '19

Hi, This is Siddhartha Sen, a student of Information Science and Engineering. I am proficient in C++ and am particularly interested in sorting algorithms. Being a GSOC aspirant, I was looking to pair up with a potential mentor in this domain, who could give me some much needed guidance. Thank You

2 1

qxcalc(GSoC2019)-2
by Ggh 07 Feb '19

07 Feb '19

Some links on my page(these pages are not always online): http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html http://www.multi.fi/~ghaga/qxcalc/ http://www.multi.fi/~ghaga/qxcalc/download.php Ty, Greg

1 0

qxcalc(GSoC2019)
by Ggh 07 Feb '19

07 Feb '19

Hi all, Not sure if there is interest, but some years ago I coded a parser/lexer with flex and yacc to do math. The project is online here "http://qxcalc.sourceforge.net/" Greg

1 0

GSoC 2019
by David Bellot 07 Feb '19

07 Feb '19

Hi Boost community, this year again we applied to the GSoC programm, Google Summer of Code. We hope to be as successfull as usual. I'm taking care of the admin work again this year. I completed an application for Boost on the Google website. It is somehow similar to our successfull applications from previous years. What we need from the community now is the following: 1) if you want to be a backup admin (I will need maybe one or two extra names at most), please let me know and I'll send you an invite. 2) if you wish to be a mentor, please let us know now and if possible on this mailing list so that students will be aware of it too. Don't forget to put the [gsoc2019] tag in the header of your email. You can write your proposals on this wiki: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 Ideally, we want to see many proposals before beginning of next week. 3) if you are a student and wants to participate, it's about time to speak loudly on the mailing list to pair with a potential mentor. The sooner the better. You can find ideas from previous years here: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code%3A-Overview Happy coding. David

7 7

find_package(Boost) support
by Peter Dimov 04 Feb '19

04 Feb '19

The current master and develop branches now install the necessary BoostConfig.cmake file (in $prefix/lib/cmake) such that f.ex. the CMake command find_package(Boost REQUIRED filesystem) will find Boost 1.70 using the config file, rather than via FindBoost.cmake (*) (if the Boost installation prefix is in CMake's prefix search path.) Interested parties are invited to test this support and share their experiences. Instead of a Git checkout, you can use the 1.70 release snapshots from https://dl.bintray.com/boostorg/master/ or https://dl.bintray.com/boostorg/develop/, as those better represent what the 1.70 release will contain. (*) Actually, the above command will invoke FindBoost.cmake, but FindBoost will look for a config file as a first step and use that, if found. To disable FindBoost completely, use find_package(Boost CONFIG REQUIRED filesystem) Or, on Windows, assuming the default C:\Boost installation, find_package(Boost REQUIRED filesystem PATHS C:/Boost)

4 4

Coordinating Parameter 'master' merging for dependent libraries
by Edward Diener 03 Feb '19

03 Feb '19

I intend to merge Parameter 'develop' to 'master' for the next release of Boost. Cromwell Enage has done a great job of adding modern improvements to the Parameter library via PRs, while maintaining full backward compatibility with the Parameter public interface. I have reviewed and approved those changes and, where I have been lax, Peter Dimov has pointed out weaknesses in some of those changes, which Cromwell has corrected. The changes which Cromwell has made have also involved improvements in the Parameter private interface(s), which have entailed some updates to the 'develop' branch of some Boost libraries which unfortunately depended on some aspects of the Parameter private interface. These updates have already been made in those other library's 'develop' branch. At this point any further possible changes for Parameter for a while will very likely be in the Parameter documentation, which requires no syncing with other libraries, so this is an excellent time for merging. Since the merging for other libraries dependent on Parameter must be synced to the merging of Parameter from 'develop' to 'master' what is the best way to go about this ? Obviously I have first to merge Cromwell's changes from 'develop' to 'master', which is easily done. How should I inform other libraries that they need to merge their Parameter dependent 'develop' changes to 'master' ? Should I create PRs for doing this ? We do not normally create PRs for the 'master' branch of any Boost library. Should I create Issues for those other libraries and hope the maintainers of the other libraries will take the appropriate action ? Or should I inform the maintainers of the other libraries in this thread, and prompt them to review their changes here to get them to merge them from 'develop' to 'master' ? The other libraries involved are: Accumulators, Log, Convert, Lockfree, Signals2, and Graph. Cromwell knows more about the specific 'develop' changes in those libraries which need to be merged to 'master' than I do, since he was instrumental in creating the PRs that would allow these libraries to work with the updated Parameters' internals, so he may chime in here, but I would like to get this done so that Parameter and its dependent Boost libraries get properly updated for the next Boost release. Of course I will also plan with Cromwell update notes for Parameter to be part of the next release.

3 2

[GSoC19] run-time Ratios
by Fenil Mehta 03 Feb '19

03 Feb '19

Hi everyone, It has been noticed that C++ provides a class to store ratios/fractions at compile-time. They provide very limited functionalities and are not modifiable during run-time. My *idea* is to have a *Ratio class* which provides all the necessary functionalities at run-time as well. I have already implemented this partially and I am willing to make it 100% ready for inclusion in Boost. Some guidance would be appreciated on how to proceed with this idea for GSoC19. Would anybody be interested in mentoring this idea for GSoC19 ? Regards, Fenil Mehta

2 1

[interprocess] 32-bit offset_ptr
by Phil Endecott 03 Feb '19

03 Feb '19

Dear Experts, I have some old code that uses 32-bit offset_ptrs, i.e. typedef boost::interprocess::offset_ptr<void, int32_t, int32_t> ptr_t; This has stopped working on 64-bit systems at some point since 1.58. git blame suggests a commit on 14 Oct 2015. There is now a static assert that checks that OffsetType is at least as large as a raw pointer. In the current case, I'm using these pointers within memory-mapped files which will always be vastly smaller than the 32-bit limit. Using 32-bit offsets seemed like a worthwhile optimisation at the time, and now I am hoping to maintain binary compatibility with those files. In the past I've also used them to save memory on 64-bit systems with pointer-heavy data structures (using boost.intrusive) using an allocator that operates within a small memory region. Has something changed within the implementation that makes this restriction necessary? Was it never supposed to work as I was using it? There is also an assert that OffsetType is unsigned, which wasn't there before. Maybe I was doing that wrong. Thanks for any advice. Regards, Phil.

3 3

[GSOC 19] Boost.ublas project Idea
by Amit Singh 02 Feb '19

02 Feb '19

Hi, My name is Amit Singh and I’m a 2nd year student. 1. I have studied last years ublas stats project and before that ublas lacked any statistics features, I would like to take boost.ublas stats further with 1. Linear Regression 2. Logistic Regression 3. Rigid Regression 4. Kernels ( Exponential Kernel, Gaussian Kernel, etc) 5. Correlation (Pearson product-moment correlation, Linear correlation, etc) 2. In ublas there is no expression solver which can solve a expression and assign the value to variable for ex:- A. matrix<double> m = “A^2 * (B * A^-1) + (det(A) * I)”; B. matrix<double> m = “A + 3” ; =>[ m = A + 3*I ] 3. In ublas to modify matrix you have to iterate using for loop. I’m hoping to create a function similar to transform in c++ or map in javascript 1. This is my small machine learning library that I implemented in c++ https://github.com/amitsingh19975/ML Would anybody be interested in mentoring my project for gsoc 19? or help me to improve my project ideas.

1 0

[thread] Passing function with parameters to boost::barrier
by André Offringa 01 Feb '19

01 Feb '19

Hi Boost developers, I'm having a problem with passing a completion function to a boost::barrier, causing a segfault, and I suspect it is a bug in the barrier code. The following is a minimal example that shows the problem: #include <boost/thread/barrier.hpp> void func(int) { } int main() { boost::barrier b(1, std::bind(func, 42)); b.wait(); } Running inside gdb and doing a bt shows some infinite recursion happening, starting with: #0 0x000055555555e41a in boost::thread_detail::decay_copy<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( t=<error reading variable: Cannot access memory at address 0x7fffff7feff0>) at /usr/include/boost/thread/detail/move.hpp:355 #1 0x000055555555d814 in boost::detail::nullary_function<void ()>::nullary_function<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( this=0x7fffff7ff0c0, f=...) at /usr/include/boost/thread/detail/nullary_function.hpp:81 ... When I change "std::bind(func, 42)" to just "func" (and declare func without parameters), it does work and the program exits normally. Passing a lambda to barrier (e.g. barrier(1, [&]() { func(0); } ) ) causes the same segfault, and the same holds when I change std::bind to boost::bind. I'm using Boost 1.67 on Debian Linux, amd64, gcc 8.2.0. Is this a bug? Cheers, André

2 1

[asio]https significantly reduce performance
by lx 31 Jan '19

31 Jan '19

Hi Boost experts: I build a https server from asio example of server2, let it support ssl.we use the codes from: *https://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/example/http/server2/main.cpp <https://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/example/http/serv…>* *https://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/server.cpp <https://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/serve…>* I complie the codes with boost_1_64 and openssl-1.1.0j, the commed line of complie is: *g++ -g -Wall -o https_server2 *.cpp -I/usr/local/include/ -I/usr/local/openssl-1.1.0j/include -L/usr/local/openssl-1.1.0j/lib -I/usr/local/boost_1_64_0/include /usr/local/boost_1_64_0/lib/libboost_thread.a /usr/local/boost_1_64_0/lib/libboost_system.a -Wl,-Bstatic -lglog -lunwind -Wl,-Bdynamic -lpthread -lcrypto -lssl -ldl -lrt* I test the https_server2 by ngrinder, the TPS is just 400, If I test is just http request , the TPS is 36000. So https significantly reduce performance. The perf top result is: [image: 1.png] The top result is: [image: 2.png] When I test it by http request, the top result is: [image: 4.png] I have push the codes on github. https://github.com/lxlenovostar/Programming_language/tree/master/cpp/test/s… I test 2, 4, 8, 24, 32 threads,but this can't improve the TPS.I test the nginx with 32 worker process, The TPS is about 5000. So maybe lock in asio ? btw: cpu is 32 cores, and Intel(R) Xeon(R) CPU E5-2440 v2 @ 1.90GHz memory is 66GB. os is CentOS 6.5 kernel is 2.6.32 Thank you.

5 6

[gsoc19][astronomy]
by Pranam Lashkari 30 Jan '19

30 Jan '19

Hello everyone, Last year I worked on the new astronomy library[0] and successfully completed GSoC with the help of my mentor *Vinícius dos Santos Oliveira*. In last GSoC, I completed basic coordinate systems and FITS file reading. *Current State of the Library:* Currently, this library has 7 basic astronomical coordinate systems implemented (Alt-Az, CIRS, ICRS, Galactic, Geocentric, Heliocentric, Supergalactic) which as actually wrappers around Boost::Geometry. IO module provides support for FITS reading. Right now, It can read primary HDU and image extensions. Development during GSoC can be found on the master branch[1] To preserve all the development done during the period of GSoC a separate branch was created after completion of GSoC named "gsoc18"[2]. All the development done after the period of GSoC can be found on develop branch[3]. No changes were merged to master after GSoC 18. *Idea for Boost GSoC19:* After communicating with the Boost::geometry community, integration of Boost::geometry and Boost::units is not supported and without using units scientific calculations are not error proof. As a result current coordinate systems can not be used with large projects as there are high possibilities of error. So this year I would like to implement Boost::unit with Boost::astronomy::coordinate to provide a robust astronomical coordinate system. Apart form this I would also complete the remaining parser for the FITS to read complete file including all types of extensions. I am targeting to complete the first coordinate system and FITS reader at the end of this GSoC and making this library ready for its first release. [0]: https://summerofcode.withgoogle.com/projects/5503102778605568 [1]: https://github.com/BoostGSoC18/astronomy/tree/master [2]: https://github.com/BoostGSoC18/astronomy/tree/gsoc18 [3]: https://github.com/BoostGSoC18/astronomy/tree/develop Thank you, Pranam Lashkari

2 2