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[Fit] Update: Request for feedback
by Paul Fultz II 06 Feb '17

06 Feb '17

Hi, I have made a lot of updates to the Fit library based on the changes suggested during the review earlier this year. I have also improved the documentation. I have expanded on the introductory materials and have add a lot more cross-referencing. The documentation can be found here: http://fit.readthedocs.io <http://fit.readthedocs.io/> Let me know of any feedback about the library either here on the mailing list or on Github issues. Thanks, Paul

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Requirements: min and max macros
by Vinnie Falco 05 Feb '17

05 Feb '17

From http://www.boost.org/development/requirements.html#Naming "Make sure your code compiles in the presence of the min() and max() macros. Some platform headers define min() and max()macros which cause some common C++ constructs to fail to compile. Some simple tricks can protect your code from inappropriate macro substitution:..." There is one case not addressed. What to do with this: std::min<std::size_t>(a, b); ?

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[build] Pre-built libraries and targets
by Edward Diener 04 Feb '17

04 Feb '17

In a jamfile I have: lib user32 ; lib gdi32 ; exe test1 : main.cpp user32 gdi32 ; According to the Boost Build documentation the 'lib' syntax above refers to pre-built libraries, and not libraries I mean to build as a shared or static library. When I run b2 with a particular toolset, and use the --debug-building option to see what targets are being built, I see results of: Building target '../../../libs/test_local/build/user32'... and Building target '../../../libs/test_local/build/gdi32'... Furthermore the build of the test1.exe does not add the user32 or gdi32 pre-built libraries to the linker command line. Can anyone tell me why Boost Build is attempting to build a target for a library which I specify as a pre-built library ?

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Call for Submissions: International Conference on Information Society (i-Society 2017) || July 17-19, 2017, Dublin, Ireland
by David Brown, i-Society 2016 03 Feb '17

03 Feb '17

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Mail Lists Migrate at 00:00 UTC Feb 3
by Michael Caisse 02 Feb '17

02 Feb '17

The following mail lists will be switched to new infrastructure at 00:00 UTC on February 3rd. There will be a small interruption while the DNS/MX records propagate. * Boost - Boost developers' mailing list * Boost-announce - Boost announce-only mailing list * Boost-bugs - Bugs reported/updated through Boost's Trac * Boost-build - Boost.Build developer's and user's list * Boost-cmake - Discussion of the CMake-based build system for Boost * Boost-commit - Boost Subversion commit messages * Boost-docs - Discussion of Boost Documentation * Boost-Interest - Moderated announcements of interest to the Boost community. * Boost-maint - Boost community maintenance mailing list * Boost-mpi - Discussion of Boost.MPI development * Boost-test - Test list for the boost mailing lists * Boost-Testing - Running Boost regression tests * Boost-users - Boost Users mailing list * Geometry - Boost.Geometry library mailing list * glas - Generic Linear Algebra Software * proto - Discussions about Boost.Proto and DSEL design * threads-devel - Discussions about the boost.thread library * ublas - ublas mailing list -- Michael Caisse Ciere Consulting ciere.com

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[factory][bind] C2664 with MSVC 2015 & 1.63
by Jens Weller 02 Feb '17

02 Feb '17

Hello Boost, I'm having this Problem: http://lists.boost.org/boost-users/2015/04/84176.php That message already describes pretty much what I see, except that I use 1.63 and the latest 2015 VC++. Errormessage: D:\cpp\libraries\boost_1_63_0\boost\bind\bind.hpp:388: error: C2664: 'ListsModuleWidget *boost::factory<ListsModuleWidget *,void,boost::factory_alloc_for_pointee_and_deleter>::operator ()(void) const': cannot convert argument 1 from 'Module *' to 'Module *&' bind.hpp code: > template<class R, class F, class A> R operator()(type<R>, F & f, A & a, long) > { > >>this line return unwrapper<F>::unwrap(f, 0)(a[base_type::a1_], a[base_type::a2_], a[base_type::a3_]); > } Compiler says: ..\..\..\..\cpp\libraries\boost_1_63_0\boost/bind/bind.hpp(388): error C2664: 'ListsModuleWidget *boost::factory<ListsModuleWidget *,void,boost::factory_alloc_for_pointee_and_deleter>::operator ()(void) const': cannot convert argument 1 from 'Module *' to 'Module *&' ..\..\..\..\cpp\libraries\boost_1_63_0\boost/bind/bind.hpp(1342): note: see reference to function template instantiation 'R *boost::_bi::list3<boost::arg<1>,boost::arg<2>,boost::arg<3>>::operator ()<ListsModuleWidget*,F,boost::_bi::rrlist4<A1,A2,A3,A4>>(boost::_bi::type<ListsModuleWidget *>,F &,A &,long)' being compiled with [ R=ListsModuleWidget *, F=boost::factory<ListsModuleWidget *,void,boost::factory_alloc_for_pointee_and_deleter>, A1=Module *, A2=const QString &, A3=const QString &, A4=QWidget *, A=boost::_bi::rrlist4<Module *,const QString &,const QString &,QWidget *> ] cheers, Jens Weller

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[outcome] Feedback on parts A and B of Tutorial mk III requested
by Niall Douglas 02 Feb '17

02 Feb '17

Dear Boost, I am truly hoping that this will be the last time I ask for feedback on Outcome's tutorial as this is the third complete rewrite. Many thanks for all the feedback so far, this Mk. III tutorial wouldn't look like this without all your help. Part A is 100% on pure expected<T, E> as currently before the standards committee. It has nothing to do with Outcome, but places Outcome in context. Part B is a polemic on why people should not use arbitrary type E in expected<T, E> and instead should restrain themselves to either E = std::error_code or E = std::exception_ptr. I'm requesting feedback on parts A and B of the tutorial which I think are mostly complete now. Specific feedback on these topics is particularly welcomed: 1. I've tried to make some of the code examples in Part A less contrived. Are there any obviously specific additional things I can do (note Parts B and C have more realistic programs)? 2. Are you convinced by the end of Part B that using arbitrary types for type E is a bad idea? If not, what did I fail to do in my explanation? Many thanks in advance. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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filtering_streambuf: Compressing a character buffer
by Adlai Shawareb 02 Feb '17

02 Feb '17

Hi, I have a character buffer ( "buffer" ) of known size ( "size_in_bytes" ), and would like to compress it using gzip_compressor and then get a pointer to the compressed buffer along with the compressed size. I've put together the following, but it says the first counter is 0 and the second counter is 2. Any help that can be offered is appreciated. namespace io = boost::iostreams; boost::asio::streambuf sb; std::ostream os(&sb); os.write( buffer, size_in_bytes ); io::filtering_streambuf<boost::iostreams::output> out; out.push(io::counter()); out.push(io::gzip_compressor()); out.push(io::counter()); out.push(os); io::close(out); // Needed for flushing the data from compressor std::ostream output(&out); // Maybe I can use rdbuf() to get the pointer to the stream?

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[type_erasure] Inefficient extra shared_ptr copy when passing parameter of type _self
by Yuanchen Zhu 01 Feb '17

01 Feb '17

Hi List, I have been using boost::type_erasure a bit. I found that in the case of implementing equality_comparable, when it passes into operator== a placeholder argument corresponding to some any<C, T>, it always wraps it in a param<C, T>, which internally instantiates an any<C, T&>. While this instantiation does not cause the actual content to be copied, it always clone the share_ptr pointing to the dispatch table, causing an extra shared_ptr construct/destruct invocation whenever I do an equality comparison. This source of inefficiency seems unnecessary to me. Is it possible to modify param<C, T> such that it only stores non-ref counted raw reference to the original argument? Of course the functions in type_erasure::detail::access need to be updated accordingly. Will this modification break some grander scheme underlying type_erasure that I am unaware of, being new to the code base? It seems to me that when param<C, T> wraps a temporary, the temporary is guaranteed to live past the lifetime of the invocation. Can people vet this idea before I take a stab at changing the code? Thanks, Yuanchen

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[serialization][uBlas] Serialization still breaking anything that uses uBlas?
by John Maddock 01 Feb '17

01 Feb '17

See for example: http://www.boost.org/development/tests/develop/developer/output/teeks99-02-… I'd really like to get these failures off my radar if possible... Thanks, John.

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[testing] Need optimization help!!!
by Rene Rivera 01 Feb '17

01 Feb '17

If someone is interested in an optimization challenge here's your opportunity. Currently the program(s) that generate the test results take a long time to run. In both the live setup of a 4 core 16 GB ram VM it takes about 40 minutes to generate the reports for master and develop branches. On my 4 core 16 GB ram real hardware SSD HD machine it also takes about 40 minutes. If some brave soul could look into why it's so terribly slow the Boost community would be very grateful. As it would make it possible to move the processing to a CI service and improve results reliability and frequency. Unfortunately the only price I can promise for such a task is to buy you a meal and/or some drinks if I see you :-) If you are interested all that's needed to run the results is: a) A good chunk of disk space.. At least 27GiB. b) A bash shell, and Python, and git, and C++ tools (but you probably already have all that). b) An empty directory to run the reports. c) Download this script < https://github.com/boostorg/regression/blob/develop/reports/src/build_resul… >. d) Comment out the upload commands on lines 220-223. e) Run the script, and wait. And then the fun part of finding out what programs get run and what is slow :-) FYI.. The source for the processing is downloaded by the script. But you can find it here < https://github.com/boostorg/regression/tree/develop/reports>. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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Re: [boost] Is there any interest in non-owning pointer-like types?
by Joseph Thomson 01 Feb '17

01 Feb '17

On 1 Feb 2017 7:51 p.m., "Olaf van der Spek" <ml(a)vdspek.org> wrote: On Wed, Feb 1, 2017 at 12:39 PM, Oswin Krause <Oswin.Krause(a)ruhr-uni-bochum.de> wrote: > On 2017-02-01 12:02, Olaf van der Spek wrote: >> >> On Wed, Feb 1, 2017 at 11:24 AM, Oswin Krause >> <Oswin.Krause(a)ruhr-uni-bochum.de> wrote: >>> >>> For me, the biggest problem of the proposal is that observer_ptr<T> is >>> implicitely constructed from T&. In my code I often use: >>> >>> Foo a; >>> Bar b(&a);//&a signals that b only references to a, but does not copy it. >>> >>> Now, when I write >>> >>> Bar b(a); //so is a now copied? >>> >>> While the interface is clearer in documentation, the usage is less clear! >> >> >> IMO using pointers instead of references to indicate something isn't >> copied is bad practice.. the language is C++, not C. > > > > This is not a C vs C++ thing. > > But assume it was. How would you indicate that in C++? It should be clear > without looking at the reference whether it is okay for a to go out of scope > before b or not. There's no way to indicate that, AFAIK. The way to indicate it is to require explicit conversion from `T&` to your pointer-like type. `make_observer` can play the role of a type-safe `&`. I would be happy to remove implicit conversion from `T&` if it is agreed to be undesirable. Joseph

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Re: [boost] Boost XML Serialization Stability across library versions
by Adlai Shawareb 01 Feb '17

01 Feb '17

Thanks Robert, Regarding your suggestion to use text serialization. Since, over time, we will be adding and deleting data from the data set that we serialize, would the following be the right approach to managing the changes in the data that is de/serialized. I'm thinking that we would set the BOOST_CLASS_VERSION before de/serializing. { ar & mInt; If(version >= 2) ar & mFloat; If(version >= 3) ar & mInt2; ar & mFloat2; } Regards, Adlai On 1/25/17 12:04:00, Robert Ramey wrote: > Right. No one as under taken that task. Should be fairly straight > forward using spirit v3. > Robert Ramey

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[container] ::flat_map function force_copy break strict-aliasing on gcc < 4.4
by Владислав Щапов 31 Jan '17

31 Jan '17

Hello! On function: template<class D, class S> BOOST_CONTAINER_FORCEINLINE static D force_copy(S s) { D *vp = reinterpret_cast<D *>(&s); return D(*vp); } gcc 4.3.4 (SLE 11) produced wrong code. It seems that the compiler does not create a copy of an object "s" and returns an object of D(). If I change the signature of function on "BOOST_CONTAINER_FORCEINLINE static D force_copy(const S& s)" the code works and the tests pass. But then does not create a copy of an object "s" in a function call. I'm not sure that this change is correct. Is there any other workaround for this problem with a compiler gcc 4.3 or better disable strict-aliasing? -- Best regards, Vladislav

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C++Now 2017 Registration is Open
by Jon Kalb 31 Jan '17

31 Jan '17

Boost Devs, Registration for C++Now 2017 is now open: http://bit.ly/CppNow2017IsOpen The conference will be in Aspen, Colorado from May 15th to 20th. The deadline for submissions is this Friday: http://cppnow.org/2017-conference/announcements/2017/01/06/call-for-submiss… Jon

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[CallableTraits] Still seeking Review Manager
by Barrett Adair 31 Jan '17

31 Jan '17

Hi, I'm still seeking a review manager for my CallableTraits library. I have spent hundreds of hours on this library, most of which went toward documentation and cross-platform testing. I think a small subset of the features in CallableTraits belong in the C++ standard. Occasionally at work, I have wished this were in Boost already. In short, this library eliminates the need to specialize templates for function signatures, and accounts for the *many* corner cases and cross-platform quirks that most users never care to do thoroughly themselves. I have 9 issues remaining on the GitHub page that would be resolved before an eventual acceptance, and I'd like to write some additional tests and documentation, but I think this library is ready for a review manager. Would anyone like to volunteer? https://github.com/badair/callable_traits Thanks, Barrett

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[regression] Are tests not running?
by Andrey Semashev 31 Jan '17

31 Jan '17

Hi, Looking at the regression tests table, it looks like the latest regression tests were run last Saturday, November 26th. It seems inlikely that all testers decided to stop running 4 days ago or are running tests for that long. Is there some problem with the regression infrastructure?

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Re: [boost] [sort] pdqsort
by Orson Peters 30 Jan '17

30 Jan '17

Hi, Orson here, I'm the original author of pdqsort. As discussed in this long github issue ( https://github.com/boostorg/sort/issues/11) I have full copyright on the pdqsort implementation (which is freely available under the zlib license on https://github.com/orlp/pdqsort) and am willing to provide it to Boost free of charge under the Boost license. @Marc Glisse, since your 2015 experiment the code has changed, and pdqsort now uses a technique called block quicksort. It's substantially faster for branchless comparisons (50-80%), but it seems that on some systems it also give significant (5-15%) slowdowns for branchful code. I will revert pdqsort's default implementation to the old version, except when the passed in type is built-in, and the comparison operator is std::less / std::greater, then I will use the branchless code. I will provide the branchless code explicitly as well, under a different function name, for experienced users that know their comparison function is branchless. The old implementation was never slower than std::sort in my experiments, for the record. If any of you have further questions, please do let me know.

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[rational] Compilation issues on VS2013+
by Raffi Enficiaud 30 Jan '17

30 Jan '17

Hi Boost, I am having the following issues when compiling boost.test on develop: http://www.boost.org/development/tests/develop/developer/output/teeks99-09e… It seems that the problem is related to rational (worked for the 1.63 release), but I am not sure. Thanks! Raffi

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[Beast] WebSocket is now feature-complete!
by Vinnie Falco 29 Jan '17

29 Jan '17

I'm pleased to announce that Beast 1.0.0-b24 has been pushed to the master branch, making Beast's WebSocket implementation feature complete with respect to RFC 6455 ("The WebSocket Protocol") and draft-ietf-hybi-permessage-compression-28 ("Compression Extensions for WebSocket). The latest version adds support for the "permessage-deflate" extension, which allows WebSocket messages to be compressed using the deflate algorithm. Beast comes with a header-only port of ZLib to modern C++11, no additional library is necessary to use the extension. The library now passes every test in the Autobahn TestSuite including compression tests. Official Repository https://github.com/vinniefalco/Beast/ Documentation http://vinniefalco.github.io/beast/index.html Autobahn TestSuite results http://vinniefalco.github.io/autobahn/index.html Thanks! -- Follow me on Github: https://github.com/vinniefalco

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[Boost.Lockfree] Interest in a ringbuffer class
by Raphaël Londeix 27 Jan '17

27 Jan '17

Hi everyone, Is there any interest in having a lower level ringbuffer type in Boost.Lockfree ? The containers provided today in the library can only store homogeneous types of fixed size. At work, we have refined many implementations of ringbuffer classes that allow one to push/pop raw buffers. Before investing some time into a pull request, I wanted to know if there's some interest in such a type. The interface looks like this: template<typename Self, typename... Policies> class basic_ringbuffer { public: typedef ... buffer; public: buffer* start_write(size_t); void commit_write(size_t); void commit_write(buffer const*); buffer const* start_read(); void commit_read(size_t); void commit_read(buffer const*); public: void reader_reset(); void writer_reset(); private: buffer* _ring() { return static_cast<Self>(*this).ring(); } }; Of course, these are only the lowest level methods, one could implement push()/pop() or other higher level methods. Beyond the fact that this API provides by default zero-copy semantics, this interface is also agnostic to the actual owner of the memory, which allow users to implement custom ringbuffers easily (shared memory, mmap trick to map the beginning at the end, etc.), for example: class custom_ringbuffer : basic_ringbuffer<custom_ringbuffer, SomePolicies...> { buffer* ring() { return some_memory; } }; The usage would look like: custom_ringbuffer rb; // the write side if (auto buf = rb.start_write(100)) { memcpy(buf.data, "some data", 9); rb.commit_write(9); } // the read side if (auto buf = rb.start_read()) { std::cout << std::string_view(buf.data, buf.size) << std::endl; rb.commit_read(buf); } What do you think ? Did I miss something in boost itself ? Should I give a more complete overview of the API ? Cheers, -- Raphaël Londeix http://hotgloupi.fr

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[outcome] Requesting second pre-review of Boost.Outcome tutorial
by Niall Douglas 27 Jan '17

27 Jan '17

Dear Boost, Last November you gave me some valuable feedback on rewriting the tutorial for Boost.Outcome, a C++ 14 library providing a factory and family of policy driven lightweight monadic value-or-error transports. I recently came out of employment contract and so have had the time to rewrite Outcome's Tutorial (anyone interested in employing a remote working C++ consultant please do get in contact). I'd appreciate feedback on https://ned14.github.io/boost.outcome/: 1. Is this rewritten tutorial too simple, too detailed or about right? 2. Do you feel you could use Outcome in your own code without difficulty after reading it? If not, what information is missing? 3. Are you persuaded of the merits of using Outcome after reading it? If not, what else do I need to say? The first FOUR sections at https://ned14.github.io/boost.outcome/ have been rewritten by me to hopefully reflect the feedback you gave me last November, so these have been refactored so far: * Description, Prerequisites and Support * Installing, building and testing Outcome * Quick start for the expert * Tutorial The package repo install methods haven't been implemented yet, these are marked in the docs as todo. These sections have yet to be refactored: * Frequently Asked Questions * Advanced usage: Outcome as a Monad * Outcome and the upcoming std::expected<T, E> Many thanks in advance for any feedback received. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Why is this message in Spam?
by Olaf van der Spek 26 Jan '17

26 Jan '17

Hi, > Why is this message in Spam? It has a from address in microsoft.com but has failed microsoft.com's required tests for authentication. Learn more I think this list isn't configured properly.. and this causes some messages to end up in Spam consistently.. Who's responsible for the mailing list infrastructure? Gr, -- Olaf

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[sort] pdqsort
by Steven Ross 26 Jan '17

26 Jan '17

I've been reviewing a proposed addition to Boost.Sort called pdqsort. When using a general-case partitioning algorithm, it performs comparably to std::sort in my testing (Windows and Linux). When used as a replacement for the std::sort fallback in spreadsort, using a branch-reducing optimization it is ~20% faster on ints and floats, and ~40% slower on strings. The concerning part is that any comparison operator that involves a branch may have a comparable slowdown to the string case. pdqsort is also significantly faster than std::sort on mostly-sorted data and some other (relatively common) special cases. This makes little difference when used as a fallback by spreadsort, but does make a difference when used on its own. I see these possible things to do with pdqsort: 1) Reject it completely as too similar to std::sort, which is already highly optimized. 2) Add it as another optional library in the Boost.Sort library. 3) Add it to Boost.Sort, and only use it as a fallback for ints and floats. 4) Add it to Boost.Sort, use it as a fallback for all of spreadsort, and have pdqsort itself only use its branch-reduction optimization on ints and floats. 5) #4, except eliminate the branch-reduction optimization completely from pdqsort for simplicity. Does anyone have a strong preference, advice, or comments on how they use Boost.Sort? Should I run a mini-review for pdqsort?

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bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

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