- Boost-users - lists.preview.boost.org

Assigning to a boost::asio::ssl::context while asynchronous operations are using it
by Martijn Otto 30 Sep '19

30 Sep '19

I cannot find any definitive documentation on whether it's safe to move-assign to an ssl-context while it is used for asynchronous operations, assuming of course the application is single-threaded. In my tests I could not trigger any failures, but that may be pure luck (or not lucky at all depending on point of view).

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catmull_rom returning a single point
by hgrwilson 30 Sep '19

30 Sep '19

Hi all, I am trying to interpolate some data with a *catmull_rom* spline available in boost math (interpolation). However, the resulting spline collapses to a single point for all /s/, corresponding to the first control point, /points_intr[0]/. Below, the c++ code segment of the interpolation is depicted: std::vector<std::array<double, 2>> points_intr(16); points_intr[0] = { 1.263270, 0.774614 }; points_intr[1] = { 1.876, 2.480 }; points_intr[2] = { 1.651110, 4.550 }; points_intr[3] = { 1.426340, 5.688 }; points_intr[4] = { 1.429, 7.054 }; points_intr[5] = { 2.073220, 8.377020 }; points_intr[6] = { 3.910, 9.140 }; points_intr[7] = { 6.430, 9.537 }; points_intr[8] = { 8.950, 9.859 }; points_intr[9] = { 11.470, 10.317 }; points_intr[10] = { 12.730, 10.6456 }; points_intr[11] = { 13.990, 11.0741 }; points_intr[12] = { 15.335, 11.6928 }; points_intr[13] = { 16.680, 12.5661 }; points_intr[14] = { 18.3538, 14.830 }; points_intr[15] = { 18.700, 16.056 }; boost::math::catmull_rom<std::array<double, 2>> interpolator_cr(std::move(points_intr)); auto max_s = interpolator_cr.max_parameter(); std::array<double, 2> inter_points; for (int i = 0; i < 100; i++) { inter_points = interpolator_cr(max_s * (i / num_points)); geometry_msgs::Point p; p.x = inter_points[0]; p.y = inter_points[1]; p.z = z; //p.z = inter_points[2]; marker.points.push_back(p); DEBUG_INFO("spline %d: (x, y) %f, %f, current_s: %f", i, p.x, p.y, max_s * (i / 100.0)); } I'm using boost 1.71.0 -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

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[Log] using std::shared_ptr and other std primatives rather than the boost counterparts
by Sean Farrow 30 Sep '19

30 Sep '19

Hi, Is is possible ot use std::shared_ptr and other std primatives with boost.log rather than the boost counterparts. I'm converting a codebase from boost namespaces and would like to add logging. Thanks, Sean.

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Re: [Boost-users] <boost/timer/timer.hpp> deprecated ?
by Kenneth Porter 23 Sep '19

23 Sep '19

--On Friday, September 13, 2019 3:35 PM +0100 "avib369 . via Boost-users" <boost-users(a)lists.boost.org> wrote: > How do I get rid of this message ? You could do what it says to do?

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Community blog or tutorial posting for C++
by Matt Zand 22 Sep '19

22 Sep '19

Hi, Does anyone know if there is a way for members to post blogs or tutorials on C++ in the Boost community or website? -- Cheers, Matt Zand Cell: 202-420-9192 Work: 240-200-6131 High School Technology Services <https://myhsts.org/> DC Web Makers <https://dcwebmakers.com/> Coding Bootcamps <https://coding-bootcamps.com/>

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<boost/timer/timer.hpp> deprecated ?
by avib369 . 13 Sep '19

13 Sep '19

How do I get rid of this message ? /tmp/ma0/boost/gcc-7.3/boost_1_71_0/boost/timer.hpp:21:70: note: #pragma message: This header is deprecated. Use the facilities in <boost/timer/timer.hpp> instead. BOOST_HEADER_DEPRECATED( "the facilities in <boost/timer/timer.hpp>" ) Ta, Avi

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boost.asio: win_iocp_serial_port_service::open changes broke FTDI support
by Michael Steinberg 12 Sep '19

12 Sep '19

Hello, the changes to win_iocp_serial_port_service::open in commit c113adc19004770d945672009b3d26f9498099cd broke at least FTDI 4232H but probably all FTDI support for me. SetCommState(handle, &dcb) in new line 99 fails with error code 57. Reverting the commit seems to recover correct behaviour. Kind Regards Michael

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Building Boost with C++17 standard
by Osman Zakir 12 Sep '19

12 Sep '19

Okay, so how do I build Boost under the C++17 standard? There's something I need to do in the configuration file, right?

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Compile error using property_tree
by Rui Pedro 11 Sep '19

11 Sep '19

Hello guys, I wanted to use boost to parse an INI file. in my code i used this includes: #include "boost/property_tree/ptree.hpp" #include "boost/property_tree/ini_parser.hpp" when I compile my code "g++ test.cpp -o Test" with only this two includes I get an error from one of the included files: In file included from test.cpp:15:0: boost/property_tree/ptree.hpp:15:45: fatal error: boost/property_tree/ptree_fwd.hpp: File or directory not found #include <boost/property_tree/ptree_fwd.hpp> ^ compilation terminated. This is an error in the ptree.hpp imported file. Maybe this has a quick fix but I'm kinda new to C++. I've checked and both files exist (boost/property_tree/ptree and boost/property_tree/ptree_fwd.hpp). Thanks, Rui

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[asio] using fork in coroutine composed operations
by Stephan Menzel 11 Sep '19

11 Sep '19

Hello all, my experiments with custom composed operations in asio have led me to another question regarding the use of such methods. What do I do in order to have multiple handlers in flight, e.g. for a timer? My example is here: https://github.com/MrMoose/moose_tools/blob/master/TimedConnect.hpp I'm trying to realize an old dream in asio. A function that will take a socket and asynchronously do a resolve and connect to the result while having a timeout around the operation. Here in the test cases (lower part) is how I imagine usage: https://github.com/MrMoose/moose_tools/blob/master/test/TestAsioHelpers.cpp… This works (the unit test does...) but I think it's no good and illustrate the problem. In the coroutine impl I can safely jump in and out and resume the code represented by the coroutine object as was explained to me yesterday. But what can I do with the timer? I cannot std::move(self) into it because it gets moved again moments later and I cannot yield on the timer wait operation. I want the timer handler and the async ops handlers both be in flight and have called whichever completes first. I tried coroutine fork thinking it might be the right tool but that seems to clash with the move-self-ahead pattern which is used here. If I don't yield and set the timer to a fixed lambda (as in the example above) it seems to work but I guess that's not how it's supposed to be, right? Any hints as to how I can make this better? Cheers, Stephan

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Program Options MacOS Error
by Michael Chiu 10 Sep '19

10 Sep '19

Hi All, I was trying to use boost program options to capture a std::string like the examples in the documentation. However I keep getting the error: libc++abi.dylib: terminating with uncaught exception of type boost::wrapexcept<boost::bad_any_cast> when i try to retrieve the value from the valuemap, i.e. vm["source"].as<std::string>(); The code that I have (which right now is essentially the tutorial example) runs fine on linux but has the above error on macos. Am i doing something wrong or is this a genuine platform specific bug? Sincerely, --Michael

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Re: [Boost-users] xlcpp: use of undeclared identifier 'decltype' used in boost/thread/lockable_traits.hpp
by Roy Musselman 10 Sep '19

10 Sep '19

Greetings, While attempting to build boost 1.70.0 for IBM Power9 using the IBM XL compilers using the SPACK tool, the following errors occur repeatedly for every header file that eventually includes boost/thread/lockable_traits.hpp In file included from ./boost/thread/lock_types.hpp:14: ./boost/thread/lockable_traits.hpp:157:11: error: use of undeclared identifier 'decltype' decltype(void(boost::declval<T&>().lock())) ^ ./boost/thread/lockable_traits.hpp:165:11: error: use of undeclared identifier 'decltype' decltype(void(boost::declval<T&>().unlock())) ^ ./boost/thread/lockable_traits.hpp:173:11: error: use of undeclared identifier 'decltype' decltype(bool(boost::declval<T&>().try_lock())) ^ These errors could be resolved if the -std=c++11 compiler option is used. Attempting to use SPACK options cxxflags=-std=c++11 or cxxstd=11 failed as if they were ignored. I was able to work-around this pervasive error by adding the following line to the file tools/build/src/tools/xlcpp.jam flags xlcpp.compile.c++ OPTIONS <cxxstd>11 : -std=c++11 ; Can you update the xlcpp.jam file to support the cxxstd=11 option, similar to what is implemented in pgi.jam? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Roy Musselman IBM HPC Application Analyst at Lawrence Livermore National Lab email: roymuss(a)us.ibm.com

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[asio] writing composed operations example
by Stephan Menzel 03 Sep '19

03 Sep '19

Hi everyone, as a long time asio user I often had needs to wrap up repeating patterns of async calls for re-use. Normally I went for some kind of specialized object that wraps smaller pieces but I recently came across a series of examples which try to explain how own composed operations may be created. https://www.boost.org/doc/libs/1_71_0/doc/html/boost_asio/examples/cpp11_ex… Now, looking at the examples they are of course way over my head but since own composed operations would be very much exactly what I need I thought I'd give it a shot. But as I now look at this example here: https://www.boost.org/doc/libs/1_71_0/doc/html/boost_asio/example/cpp11/ope… I notice something that I hope somebody can explain. In the coroutine implementation it says: delay_timer_->expires_after(std::chrono::seconds(1)); yield delay_timer_->async_wait(std::move(self)); if (error) break; yield boost::asio::async_write(socket_, boost::asio::buffer(*encoded_message_), std::move(self)); I'm puzzled about the double std::move() of self. In the comments above it says that self is a reference to an intermediate completion handler. How can this be moved twice? Can anyone give me hint about what this means? I would also appreciate any hints in general about own composed operations. Perhaps there are other approaches that are a bit less intimidating? Cheers, Stephan

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[MSM] Substatemachine with constructor arguments
by jcbastosportela＠gmail.com 30 Aug '19

30 Aug '19

Hi all, My question regards boost's Meta State Machine (MSM) usage. In my current design of a state machine it would be desirable to pass arguments to the substate machine; this would be done at time of creation of "main state machine". I found something on the documentation close to what I am looking for, however not exactly. State machine constructor with arguments <https://www.boost.org/doc/libs/1_71_0/libs/msm/doc/HTML/ch03s05.html#d0e2502> . This works very well for states, but doesn't work for the substate machine. Fails in compilation with the following log: In the example <https://www.boost.org/doc/libs/1_71_0/libs/msm/doc/HTML/examples/Constructo…> found in the documentation I would changed the *Playing* substate machine to look like: and in creation of the *player* to do something like: See the file attached. msm_substm.cpp <http://boost.2283326.n4.nabble.com/file/t371477/msm_substm.cpp> Is there a way of achieving this? Many thanks in advance. Regards, Joao Portela -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

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Re: [Boost-users] Template specialization for Boost.Polygon
by Bjorn Reese 28 Aug '19

28 Aug '19

On 8/26/19 5:39 PM, Phil Endecott via Boost-users wrote: > Can anyone suggest how I can write my specialisations so that they > are unambiguous? By adding another level of indirection. Create your own trait template. Let both the generalization and your specialization redirect to polygon_traits. Something like this (warning untested code ahead) template <typename T, typename Enable = void> struct my_polygon_traits : public polygon_traits<T, Enable> { }; template <std::size_t N> struct my_polygon_traits<std::array<Point, N>> : public polygon_traits<std::array<Point, N>> { };

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Template specialization for Boost.Polygon
by Phil Endecott 26 Aug '19

26 Aug '19

Dear Experts, This is a question about Boost.Polygon but please keep reading even if you've never used that library as it's really just about how to resolve ambiguous template specialisations. Boost.Polygon has a mechanism by which you can tell it about your own types by specialising templates. I want to tell it that std::array<Point,N> is a polygon, which I try to do like this: template <size_t N> struct geometry_concept< std::array<Point,N> > { using type = polygon_concept; }; template <size_t N> struct polygon_traits< std::array<Point,N> > { ....... }; This doesn't work because of ambiguity between that specialisation of polygon_traits and a default specialization that is in the library itself; the library code looks something like this: template <typename T, typename enable = gtl_yes> struct polygon_traits {}; template <typename T> struct polygon_traits<T, ...some SFINAE stuff.... > { ......... }; If I try to just specialize one size of array it works: template <> struct polygon_traits< std::array<g2i::Point,3> > { ....... }; The error is: test_template_specialization.cc:64:19: error: ambiguous partial specializations of 'polygon_traits<std::__1::array<Point, 3>, boost::polygon::gtl_yes>' boost::polygon::polygon_traits<std::array<Point,3>>::iterator_type i = nullptr; ^ /usr/local/include/boost/polygon/polygon_traits.hpp:100:10: note: partial specialization matches [with T = std::__1::array<Point, 3>] struct polygon_traits<T, ^ test_template_specialization.cc:32:8: note: partial specialization matches [with N = 3] struct polygon_traits< std::array<Point,N> > ^ I have the same issue when I attempt to use a Point class that takes the coordinate type as a template parameter. Can anyone suggest how I can write my specialisations so that they are unambiguous? A complete test program follows. I'm testing with Boost 1.69.0, but I don't think anything has changed in Polygon since then. Thanks, Phil. #include <boost/polygon/polygon.hpp> #include <array> struct Point { int x; int y; }; namespace boost { namespace polygon { template <> struct geometry_concept<Point> { using type = point_concept; }; template <> struct point_traits<Point> { using coordinate_type = int; static inline coordinate_type get(const Point& point, orientation_2d orient) { return (orient==HORIZONTAL) ? point.x : point.y; } }; template <size_t N> struct geometry_concept< std::array<Point,N> > { using type = polygon_concept; }; template <size_t N> struct polygon_traits< std::array<Point,N> > { using coordinate_type = int; using iterator_type = typename std::array<Point,N>::const_iterator; using point_type = Point; static inline iterator_type begin_points(const std::array<Point,N>& p) { return p.begin(); } static inline iterator_type end_points(const std::array<Point,N>& p) { return p.end(); } static inline std::size_t size(const std::array<Point,N>&) { return N; } static inline winding_direction winding(const std::array<Point,N>&) { return unknown_winding; // Hmm. } }; }; }; // namespace boost, polygon int main() { boost::polygon::polygon_traits<std::array<Point,3>>::iterator_type i = nullptr; return 0; }

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Help building one module with cross-compiler
by Adrian C 25 Aug '19

25 Aug '19

Hi, I am trying to build boost module "log" on a raspberry PI as a dependency to another project. The RPI runs out of virtual memory during the build process, although I do limit building to just log (I think it builds some dependencies though). So I decided to cross compile it on a x86 machine with plenty of resources. I followed the instructions and built using: BUILD_CXXFLAGS="-std=gnu++11 -pthread" BUILD_CXX=arm-linux-gnueabihf-gcc ./bootstrap.sh --with-libraries=log --with-toolset=cross-cxx The build fails with the bootstrap.log showing the content below. Your advice is appreciated. thank you ubuntu@ryu:~/arm-toolkit/boost_1_71_0$ cat bootstrap.log######### Using 'cross-cxx' toolset.######arm-linux-gnueabihf-gcc --versionarm-linux-gnueabihf-gcc (crosstool-NG linaro-1.13.1+bzr2650 - Linaro GCC 2014.03) 4.8.3 20140303 (prerelease)Copyright (C) 2013 Free Software Foundation, Inc.This is free software; see the source for copying conditions. There is NOwarranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ######arm-linux-gnueabihf-gcc -std=gnu++11 -pthread -DNDEBUG builtins.cpp class.cpp command.cpp compile.cpp constants.cpp cwd.cpp debug.cpp debugger.cpp execcmd.cpp filesys.cpp frames.cpp function.cpp glob.cpp hash.cpp hcache.cpp hdrmacro.cpp headers.cpp jam.cpp jambase.cpp jamgram.cpp lists.cpp make.cpp make1.cpp md5.cpp mem.cpp modules.cpp native.cpp object.cpp option.cpp output.cpp parse.cpp pathsys.cpp regexp.cpp rules.cpp scan.cpp search.cpp strings.cpp subst.cpp sysinfo.cpp timestamp.cpp variable.cpp w32_getreg.cpp modules/order.cpp modules/path.cpp modules/property-set.cpp modules/regex.cpp modules/sequence.cpp modules/set.cpp execunix.cpp fileunix.cpp pathunix.cpp -o b2/tmp/ccFB5qkl.o: In function `(anonymous namespace)::std_thread_hardware_concurrency()':sysinfo.cpp:(.text+0x118): undefined reference to `std::thread::hardware_concurrency()'collect2: error: ld returned 1 exit status

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License Issue with boost_intrusive
by Gerald Wiltse 23 Aug '19

23 Aug '19

During an annual third-party audit of our source code, boost intrusive was flagged as containing unlicensed code. Specifically, there are several pieces of code in this file which are explicitly attributed to external parties on external websites, which still exist and show no license. https://github.com/boostorg/intrusive/blob/develop/include/boost/intrusive/… https://github.com/boostorg/intrusive/blob/develop/include/boost/intrusive/… Original sources: http://stackoverflow.com/questions/11376288/fast-computing-of-log2-for-64-b… http://www.flipcode.com/archives/Fast_log_Function.shtml I don't claim to be a license expert. I've read a lot over the years, but this is the first time that I've actually been between an attorney and a codebase having to figure out practical implications of a scenario like this. I first want to make sure that Boost committee is aware of this situation. Second, I would like to know what the official conclusion would be from the Boost Committee about the license implications in cases like these. Maybe it has come up before and is well established. On the surface, the implications seems ambiguous to me when: DEVELOPER_A takes unlicensed code off the internet, prefixes it with a comment that says "Thanks to DEVELOPER_B ", then prefixes the whole file with a file-level copyright notice that says "COPYRIGHT DEVELOPER_A", and then says it's distributed under BSL-1.0 license, and then the boost team re-distributes the source code. Internally at my company, there was little discussion about it. There is no room for ambiguity, so the directive from management was to delete the file from our SCM system completely and ensure it never is included in our products. VERY fortunately, deleting it doesn't seem to have broken our builds. In future cases like this, that's really not what we want to be doing with your OSS libraries for obvious reasons. So, I'd like to know if there's any chance this situation changes in a future version of Boost (I.E., the code be removed/re-written with clean-room approach, etc). Regards, Jerry Gerald R. Wiltse jerrywiltse(a)gmail.com

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[release] Boost 1.71.0
by Michael Caisse 21 Aug '19

21 Aug '19

Release 1.71.0 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 1 new library (Variant2) and numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.71.0> You can also download directly from: <https://dl.bintray.com/boostorg/release/1.71.0/> 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 Marshall Clow, Michael Caisse

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[Dll] e0077 with BOOST_DLL_ALIAS
by Sean Farrow 20 Aug '19

20 Aug '19

Hi, I'm getting the following error when using BOOST_DLL_ALIAS to export a function to create a plugin using visual studio 2019 and boost 1.71. This isn't new, just the first time I've noticed it. E0077 this declaration has no storage class or type specifier I've cross-checked this with the example (specifically tutorial 2) to ensure that it wasn't just me. For reference, the offending line in the my_plugin_aggregator.cpp file is: BOOST_DLL_ALIAS( my_namespace::my_plugin_aggregator::create, // <-- this function is exported with... create_plugin // <-- ...this alias name ) Other than suppressing this specific error, is there any other work around given I'm compiling with treat warnings as errors enabled? Any help appreciated as always. Thanks, Sean.

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[Dll] Inconsistent annotations reported under visual studio 2019
by Sean Farrow 20 Aug '19

20 Aug '19

Hi all, Whilst compiling a plugin in release mode with boost.dll 1.70 using Visual Studio 2019 and the latest Windows sdk, I'm getting several inconsistent annotation errors for functions like LoadLibraryA/W. Before I go to the trouble of creating a reproducible project and filing an issue, I wondered whether this is something that is know about and possibly fixed in 1.71 Any help appreciated. Kind regards Sean.

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Re: [Boost-users] [release] Boost 1.71.0 Release Candidate 2 available
by Michael Caisse 16 Aug '19

16 Aug '19

On 8/16/19 10:22, William Jagels wrote: > > > On Wed, Aug 14, 2019, 13:29 Michael Caisse via Boost-users > <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> wrote: > > The release candidates for the 1.71.0 release are now available at: > <https://dl.bintray.com/boostorg/release/1.71.0/source/> > > The SHA256 checksums are as follows: > > 1b3949ffddf56129141032542523920034f2e69775fb9332a52ba37c548dbf35 > boost_1_71_0_rc2.7z > > d73a8da01e8bf8c7eda40b4c84915071a8c8a0df4a6734537ddde4a8580524ee > boost_1_71_0_rc2.tar.bz2 > > 96b34f7468f26a141f6020efb813f1a2f3dfb9797ecf76a7d7cbd843cc95f5bd > boost_1_71_0_rc2.tar.gz > > 85a94ac71c28e59cf97a96714e4c58a18550c227ac8b0388c260d6c717e47a69 > boost_1_71_0_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 > > > > Built successfully with gcc 8.3.0. Was able to rebuild a large codebase > without any issues. > Thank you for giving it a spin and reporting back! -- Michael Caisse Ciere Consulting ciere.com

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[release] Boost 1.71.0 Release Candidate 2 available
by Michael Caisse 15 Aug '19

15 Aug '19

The release candidates for the 1.71.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.71.0/source/> The SHA256 checksums are as follows: 1b3949ffddf56129141032542523920034f2e69775fb9332a52ba37c548dbf35 boost_1_71_0_rc2.7z d73a8da01e8bf8c7eda40b4c84915071a8c8a0df4a6734537ddde4a8580524ee boost_1_71_0_rc2.tar.bz2 96b34f7468f26a141f6020efb813f1a2f3dfb9797ecf76a7d7cbd843cc95f5bd boost_1_71_0_rc2.tar.gz 85a94ac71c28e59cf97a96714e4c58a18550c227ac8b0388c260d6c717e47a69 boost_1_71_0_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

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Parallel Boost logging with multiple link units
by Simon Michalke 14 Aug '19

14 Aug '19

Hello all, I want to use boost logging with multiple link units. However all of the examples use only one source file (and only have some logging in the main function). In addition to that I need to have multithreading support as well. Do I have to initialize the sink for every module or only once for my program? Regards, Simon Michalke

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Boost ASIO HTTP Server example design question
by TomJordan 12 Aug '19

12 Aug '19

Hi, I'm just starting to use ASIO. I have been reading the C++11 HTTP Server example at https://www.boost.org/doc/libs/1_70_0/doc/html/boost_asio/example/cpp11/htt… and want to make sure I understand use of shared_ptr in this example, because I didn't notice any explanation in the documentation. The connection class inherits from std::enable_shared_from_this<connection>, and is then passed in a shared_ptr (the captured 'self') to the handler function registered with the async_read_some in connection::do_read(). Is this approach, and the related design decsision that the server creates a shared_ptr to a new connection in its server::do_accept() function, taken simply in order to ensure that the connection object is kept alive for as long as any asynchronous read/write operation requires it? So is it implying that if the connection was NOT kept alive by a shared_ptr (i.e., was instead created by the server and stored by value in a std container) something bad could and likely would happen at some point, most likely due to the handler being called on an object that no longer exists? This might be when a boost::asio::error::operation_aborted is reported by the handler, when a current async operation is cancelled during the server/connection_manager shutdown process as a result of closing the socket, after the connection object value has been removed from the container, for example? Is this shared_ptr approach the idiomatic or even the only way to manage lifetimes in ASIO async calls? It just looks a bit ugly to me, bloats the code a bit and I was wondering if there is any other way to do it without the intrusion of shared_ptrs into the mix? Tom

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Interest in updated, standalone iterator_facade library?
by Zach Laine 11 Aug '19

11 Aug '19

I write a lot of iterators, and I'm getting sick of doing it by hand. I can't use Boost.Iterator's iterator_facade in library code, since it knows nothing about constexpr and noexcept. The design of Boost.Iterator's iterator_facade does not lend itself very well to being modified in a direction that is standardization-friendly (reasons why are outlined in the online docs). So, here is one take on this problem: GitHub: https://github.com/tzlaine/iterator_facade Online Docs: https://tzlaine.github.io/iterator_facade For those unfamiliar with the problem, iterators are very simple, at the highest level of abstraction. An iterator's implementation does not reflect this -- it is highly repetitive and easy to get subtly wrong. This library fixes that. The library is forward-looking, since I intend to write WG21 papers to standardize iterator_facade; there is good support for upcoming C++20 library features. In particular, the iterators created with iterator_facade model the C++20 iterator concepts, and therefore do not necessarily match the requirements of the C++17-and-earlier requirement tables. I have not found this to affect the usability of iterator-facade-based iterators with pre-C++20 code. Something to note: there was a recent-ish attempt to stanrdize iterator_facade, which is now abandoned, P0186 (http://wg21.link/P0186) This was very different from what I'm proposing for Boost. I talked to Eric Niebler about this, and he favors a return to the CRTP-based approach of my lib and the original Boost.Iterator iterator_facade library. Zach

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[rational] make rational constructors noexcept
by Frédéric 06 Aug '19

06 Aug '19

Hi, I think that some rational constructors can be marked noexcept. In particular: - default constructor: rational() - constructor from integer: rational(const T& n, typename enable_if_c<...>::type const* = 0) Concerning the constructor with numerator and denominator, if the denominator is always not null, it could be noexcept but I guess we cannot enforce not null unless we use some kind of gsl::not_null. Your thoughts? Thanks, F

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Question regarding Boost Logging to Windows Event Logs
by Art Strutzenberg 06 Aug '19

06 Aug '19

I'm encountering an issue with the boost logging system, backend is using windows event log backend, and I'm honestly not sure what might be going on? The symptoms: * My code is building, events ARE getting logged and showing up in the event viewer * There is no additional data getting associated to the event (in this case a "processID", "threadID", and actual message text. * The events that do show up have the following text: "ProcessId: %1 ThreadId: %2 Message: %3, * Additionally I'm noticing that the severity of the message is showing up as "Error" Here is the code snippets that I <think> might be relevant: https://pastebin.com/ttzK4r0m The mc file I'm using is: https://pastebin.com/fNyL5Zua Thanks! --Art

1 0

Boost.Build broken links in Getting started page
by David Demelier 01 Aug '19

01 Aug '19

Hello there, I was reading the page Getting started, but all references to Boost.Build point to 404. https://www.boost.org/doc/libs/1_70_0/more/getting_started/unix-variants.ht… Regards, -- David

1 0

Fatal Error LNK1104: cannot open file
by Cg K 30 Jul '19

30 Jul '19

I posted this issue originally on the boost list, largely to inform that I have been able to compile boost_1_71_0_b1_rc1 using VS 2019. See that post here: <https://lists.boost.org/Archives/boost/2019/07/246678.php> I moved this post here because I think my subsequent problem has to do with setting up Visual Studio 2019. I have followed the Getting Started in Windows <https://www.boost.org/doc/libs/1_70_0/more/getting_started/windows.html> tutorial and was able to build the simple program, aka the header only project, in VS. It compiled and ran fine. I then built the project that links your program to the Boost Library described in the tutorial. I received the following message when I compiled as x64. 1>LINK : fatal error LNK1104: cannot open file 'libboost_regex-vc142-mt-gd-x64-1_71.lib' As you can see in my original email post referred to above, I built another simple program based upon a youtube video and on VS2017 and while it compiled in the youtube video, I received a the same linker error, LNK1104 message as well. Since the file referred toin the LNK1104 error has the prefix lib, it appears that VS is looking for a static library. I built boost as shared from the Develop command line using the command. .\bj2 link=shared . This method apparently worked in VS2017 but I can not replicate it in VS2019. What am I missing?

2 2

Result of out_ptr review.
by Zach Laine 29 Jul '19

29 Jul '19

I've compiled the results of the reviews of out_ptr during its recent review. Unfortunately, out_ptr is NOT ACCEPTED, though many of the reviewers indicated interest in seeing it come back in some future form. I counted these formal reviews: Andrey Semashev: reject Louis Dionne: accept David Sankel: reject Phil Endecott: reject Glen Fernandes: reject Gavin Lambert: reject Thanks to all of the above reviewers, and to all those who contributed to the ongoing discussions surrounding out_ptr, even if they did not have time for a full review. Points against out_ptr raised during the review: - Many reviewers indicated their puzzlement that this library was proposed at all, since they had never seen enough calls to C APIs in their own code to motivate the need for out_ptr. - Some reviewers who did find the motivating cases of the library compelling, still said that they would prefer to write wrappers instead of using something like out_ptr. - Multiple reviewers want the library to provide error-reporting help (it currently does not). In particular, for c_func(out_ptr(p)), there was a concern about whether p is assigned a value, when c_func() returns a failure-status. - There was concern from several reviewers about the fact that out_ptr's types' dtors may throw, though this is only limited to the use of out_ptr with shared_ptr and similar smart pointers. In particular, non-unique_ptr uses will never throw in out_ptr's types' dtors, unless the user provides a throwing deleter. - Multiple reviewers disagreed with the use of template specialization as a customization mechanism. - There was widespread concern about the use of potentially UB-invoking tricks to get max performance out of the implementation. - Many reviewers wanted a more typical Boost tutorial introduction in the documentation. Now please permit me a digression. The library attempts to take a call that looks like this (simplest call possible): // CASE 0 foo * new_foo; TODO if (!create_foo(&new_foo)) { // etc. ... } And turn it into something as close as possible to this: // CASE 1 std::unique_ptr<foo> new_foo; if (!create_foo(new_foo)) { // etc. ... } out_ptr does a great job of this lexically: // CASE 2 std::unique_ptr<foo> new_foo; if (!create_foo(out_ptr(new_foo))) { // etc. ... } If you have not written thousands of lines of code that look like case 0, stop for a second and consider what it would be like to drop those thousands of raw pointers into your code, and how much you would like to replace them all with unique_ptrs. Now consider what it would take you to write all the wrapping functions necessary to make those thousands of calls look like case 1. You may make tooling to generate the wrappers, and that's time consuming. Writing it by hand is even more so. out_ptr also has the nice property that using it as I have above with unique_ptr does not change the meaning of the code, except to ensure that new_foo is guaranteed to be treated in a RAII manner. Thus we get increased exception safety, memory leak mitigation, etc. -- y'know, all that RAII stuff. If out_ptr is implemented well, case 2 should produce nearly identical object code to case 0, except that case 2 handles calling new_foo's dtor at the right time. Note that because of this, you have the same relationship to the C API in all three cases. That is, you need to check for the success value returned from create_foo(), and you need to know what create_foo()'s contract is in the face of errors -- did it write to new_foo or not? out_ptr is how you get from raw pointers to RAII ones, not how you solve all programming problems related to calling functions. Hopefully that motivates the use case for out_ptr, even if you don't need it in your own code. Hopefully that also allays concerns that out_ptr is not doing enough -- doing more is outside the library's scope. Now, on to exceptions in out_ptr's types' dtors. I heard a lot of discussion about this during the review. To me, concerns about what happens when an out_ptr or an inout_ptr throws in its dtor misses the point entirely, because it is concerned with fixing corner cases we should not even care to support. Instead of worrying about the semantics of exceptions in those kinds of situations, we should instead be asking why we want to support user code like this: ... } catch { create_foo(in_out_ptr(my_shared_ptr_to_a_foo)); ... } In other words, we don't really care about the dtor exceptions, unless: - there is an active exception already, and - we are also calling a C API to create a new object (a possible, but certainly atypical thing to do when handling an exception), and - we're catching this new object in a shared_ptr-like smart pointer that might throw on construction. Who writes code like that? Few people, perhaps none. It's not impossible to see code like that, but until there are well-motivated cases for this, maybe leave it for a later version of the library. In other words, the question should have been "Why support anything other than nothrow-constructible RAII types like unque_ptr?" Note that I find this argument compelling for the WG21-facing version of this work too. To summarize: I think the first four bullet points listed at the beginning of this post are, or could easily be made to be, irrelevant. So, that leaves some issues still outstanding: - figure out how to provide customization points (I'm actually fine with the current approach...), - eliminate the UB-dangerous code, or make it opt-in, - rework the tutorial portion of the docs, and - many assorted doc cleanups. That does not seem like an unreasonable amount of stuff to resolve in post-review acceptance readiness. I bring all this up because I do in fact hope that JeanHeyd brings this back for a future review, and I hope that my arguments here will convince some of you that this library is a useful thing to have around. I waited until now to say any of these things in an attempt to remain impartial during the review; I've been bothered by seeing previous review managers clearly represent a pro-acceptance position from the start. Thanks to JeanHeyd for his submission. A no-vote from this group is a tough thing, and I hope that the feedback he has received takes some of the sting out. Zach

6 5

Need some help with Boost.Build
by Maarten Verhage 29 Jul '19

29 Jul '19

Dear Boost.Build expert, I do have Boost 1.69 and was able to build from the sources with Mingw-w64 gcc 8.1 on Windows 7. That was for boost itself, but now I need to build the tests for the Boost library Spirit (the parser). I cannot get this to work. My Boost.Build version is 2018.02-git. According to Boost.Build paragraph 3.3 Configuration, the option "b2 --debug-configuration" gives info how my boost.build is configured. In the folder <boost-build>\example\hello the output of "b2 --debug-configuration" looks fine. But when I run from the folder <boost-spirit-develop>\test "b2 --debug-configuration" the output contains: error: Could not find parent for project at '.'. So in the folder <boost-spirit-develop>\test I rename Jamfile to Jamroot.jam. Now with "b2 --debug-configuration" I get: output.txt (attachtment of this email) Also when I try to build the tests it I gets the same error messages strarting from: config.jam: No such file or directory How do I solve this? Best regards, Maarten Verhage

1 0

boost::test observing failures
by John Foster 27 Jul '19

27 Jul '19

I am using boost test within a home-grown GUI, and want to access test results (e.g. the failure message and location when a test fails) The unit_test::test_observer class provides the virtual method: void assertion_result(boost::unit_test::assertion_result) However, unit_test::assertion_result is just an enum indicating success or failure. From there, I cannot see how to access further information about the test result. The framework also provides the class test_tools::assertion_result, which encapsulates an error message, but this only appears to be used for evaluating pre-conditions. (I would have expected this type to be the argument to unit_test::test_observer::assertion_result). The log output classes appear to provide more information on test results. These are implemented as streams, which makes it non-trivial to extract test result data. Does anyone know how I can access the information on test results - success/failure, the test code, the location, etc? Thanks John John Foster [cid:image001.png@01D3CC10.659716E0]<http://en.wikipedia.org/wiki/Qantassaurus> Associate Director, Quant Analysis Regulatory Modelling Credit Risk Analytics and Portfolio National Australia Bank Level 15, 500 Bourke St, Melbourne VIC 3000 Tel: +61 (0)3 8641 5228 Email: john.x.foster(a)nab.com.au<mailto:John.X.Foster@nab.com.au> ________________________________ The information contained in this email communication may be confidential. If you have received this email in error, please notify the sender by return email, delete this email and destroy any copy. Any advice contained in this email has been prepared without taking into account your objectives, financial situation or needs. Before acting on any advice in this email, National Australia Bank Limited (NAB) recommends that you consider whether it is appropriate for your circumstances. If this email contains reference to any financial products, NAB recommends you consider the Product Disclosure Statement (PDS) or other disclosure document available from NAB, before making any decisions regarding any products. If this email contains any promotional content that you do not wish to receive, please reply to the original sender and write "Don't email promotional material" in the subject.

2 1

[boost] [release] Boost 1.71.0 Beta 1 - déjà vu
by Michael Caisse 22 Jul '19

22 Jul '19

Note: The previous email announcement still had the rc1 tag in the filenames. This version of beta1 is identical in content to beta1 rc1. Boost release 1.71.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.71.0.beta1/source/> The SHA256 checksums are as follows: 451adc4f199c73e995e541f38c4dbd51faf4ce0db15537136ffd5213a1be5e55 boost_1_71_0_b1.7z a93d7066fc1514995aec0e726532a219447dd39b0ffa7cb97ca5736f16b0488b boost_1_71_0_b1.tar.bz2 34743b80466463e0c1b7fc71b677f326bdc242fe0b87a9c1599b6f7ea6e5c0cb boost_1_71_0_b1.tar.gz 5cd448bddc8394469391306e0ccada0a8f88c5c6cf8ec775ddf8e56adef8bbc2 boost_1_71_0_b1.zip For details of what's in the release, see <http://www.boost.org/users/history/version_1_71_0.html>. Note: Having some trouble getting the web page updated... check back with it soon. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

4 4

trying to create a vector of histograms
by damien＠khubla.com 20 Jul '19

20 Jul '19

Hi all, As the subject says, I'm trying to create a vector of histograms. This needs to be a member variable of a class so I need to get the types right in the declaration. I keep getting type conversion errors when I pass the axis to the constructor, so I'm trying a non-vector example. Here's the base code: using UU = boost::histogram::unlimited_storage<std::allocator<double> >; using AA = std::tuple<boost::histogram::axis::variable<double> >; AA ax; boost::histogram::histogram<AA, UU> histo; histo = boost::histogram::histogram(ax); //this has a conversion problem The error on VS 2017 is: error C2440: '<function-style-cast>': cannot convert from 'boost::histogram::axis::variable<double,boost::use_default,boost::use_defau lt,std::allocator<_Ty>>' to 'boost::histogram::histogram<boost::histogram::axis::variable<double,boost:: use_default,boost::use_default,std::allocator<_Ty>>,boost::histogram::defaul t_storage>' with [ _Ty=double ] note: No constructor could take the source type, or constructor overload resolution was ambiguous I can see that the types are different, but no matter what I do with the template arguments of the axis type I still get that error. Can anyone help? Damien

1 1

[release] Boost 1.71.0 Beta 1
by Michael Caisse 19 Jul '19

19 Jul '19

Boost release 1.71.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.71.0.beta1.rc1/source/> The SHA256 checksums are as follows: 451adc4f199c73e995e541f38c4dbd51faf4ce0db15537136ffd5213a1be5e55 boost_1_71_0_b1_rc1.7z a93d7066fc1514995aec0e726532a219447dd39b0ffa7cb97ca5736f16b0488b boost_1_71_0_b1_rc1.tar.bz2 34743b80466463e0c1b7fc71b677f326bdc242fe0b87a9c1599b6f7ea6e5c0cb boost_1_71_0_b1_rc1.tar.gz 5cd448bddc8394469391306e0ccada0a8f88c5c6cf8ec775ddf8e56adef8bbc2 boost_1_71_0_b1_rc1.zip For details of what's in the release, see <http://www.boost.org/users/history/version_1_71_0.html>. Note: Having some trouble getting the web page updated... check back with it soon. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

2 4

boost::filtered_graph filtering on vertex color... if I only had a colormap
by Brian Davis 19 Jul '19

19 Jul '19

Lets say I have a graph g (of type graph_t) and a color map (boy I wish I had a colormap): typedef boost::property_map<graph_t, boost::vertex_color_t>::type color_map_t; or is it? auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::default_color_type>(indexmap); or maybe? auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::vertex_color_t>(indexmap); or possibly some goop found on the internet? boost::make_iterator_property_map(color_map.begin(), boost::get(boost::vertex_index, data_->g), color_map[0]) or other internet goop? typedef boost::property_map<GraphType, boost::vertex_color_t>::type color_map_t; color_map_t colorMap; boost::color_map(colorMap)) or other internet goop?? std::vector<int> colorMap(num_vertices(g), boost::white_color); so confused... (certainly not surprised why bgl is not a part of stl) Can someone help explain the various types and ways of specifying colormaps and the logic for each way and means? and a function (if I could get that far without VS syntax highlighter going bonkers and gobs of compiler errors.. you know the type): make_pretty(g, colormap ) which colors the graph colormap and a filter struct for boost::filtered_graph<Graph, EdgePredicate, VertexPredicate> (where I wonder why if I only want to filter vertices I have to set boost::keep_all for EdgePredicate... sigh... I know the answer... and also know how long it found me to find/figure out boost::keep_all - and if you are looking for boost::keep_all and found it here... your welcome ;-) ) and modifying (probably incorrectly) boost::filtered_graph example to: template <typename ColorMap> struct vertex_color_filter_eq { vertex_color_filter_eq() { } vertex_color_filter_eq(ColorMap colormap/*, boost::default_color_type c*/) : m_colormap(colormap)/*, m_c(c)*/ { } template <typename Vertex> bool operator()(const Vertex& v) const { return 0 < get(m_colormap, v); //return c < get(m_colormap, v); } ColorMap m_colormap; //boost::default_color_type m_c; }; auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::default_color_type>(indexmap); // some where here I would call make_pretty(g, colors) typedef property_map<graph_t, boost::vertex_color_t>::type ColorMap_t; vertex_color_filter<ColorMap_t> filter(colors); // boost::filtered_graph<graph_t, boost::keep_all, VertexPredicate> boost::filtered_graph<graph_t, boost::keep_all, vertex_color_filter> fg(g, filter); // Later say if I could get it compile and better if it compiled and worked I could move on and auto color = boost::red_color; typedef property_map<graph_t, boost::vertex_color_t>::type ColorMap_t; vertex_color_filter<ColorMap_t> filter(colors, color); boost::filtered_graph<graph_t, boost::keep_all, vertex_color_filter> fg(g, filter); Maybe if I color them yellow, I can then reach the wizard pull back the curtain and ask how to create a color map... If I only had a color map.

4 6

How can I create an internal and modifiable color_map for boost DFS?
by Juergen 19 Jul '19

19 Jul '19

Hello, everybody, at the moment I am really lost. The problem is to create the color map that can be used in Depth_First_Search. A special feature that I have is that I want to change the Vertex color of DFS to modify the DFS. For example like this: If I make the color map global and pass it to the visitor, everything works: If the color map is not global but external, I can write the map, but it is not the same as the DFS color map and therefore I cannot manipulate the DFS algorithm: I then tried to create an internal map and work with the get() and put() functions, but I didn't succeed: I'd be so grateful if you'd give me a hint. -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

1 0

R: Support on Websoscket Plugin
by Clinco Fabrizio 17 Jul '19

17 Jul '19

Hello, for the Enterprise project I'm working on, we're looking for a library that implements the WebSocket Protocol (RFC 6455). As we consider your implementation very useful for our needs, we would like to know if you have a library compatible with the C ++ 98 standard on embedded emvironmant. Thank you in advance for your support, Fabrizio Fabrizio Clinco Delivery Manager Application Integration Digital Factory email: fabrizio.clinco(a)exprivia.com<mailto:fabrizio.clinco@exprivia.com> m.: +39 3427218158 [https://dbg.exprivia.it/exprivia-resources/images/Image/marchio-congiunto.j…] Exprivia S.p.A. Via Adriano Olivetti 11/a 70056 Molfetta (BA) T. +39 0803382070 F. +39 0803382077 www.exprivia.it<http://www.exprivia.it/> Exprivia Italtel Group Internet Email Confidentiality Footer ** La presente comunicazione, con le informazioni in essa contenute e ogni documento o file allegato, e' rivolta unicamente alla/e persona/e cui e' indirizzata ed alle altre da questa autorizzata/e a riceverla. Se non siete i destinatari/autorizzati siete avvisati che qualsiasi azione, copia, comunicazione, divulgazione o simili basate sul contenuto di tali informazioni e' vietata e potrebbe essere contro la legge (art. 616 C.P., D.Lgs n. 196/2003 Codice in materia di protezione dei dati personali). Se avete ricevuto questa comunicazione per errore, vi preghiamo di darne immediata notizia al mittente e di distruggere il messaggio originale e ogni file allegato senza farne copia alcuna o riprodurne in alcun modo il contenuto. Al link seguente e' disponibile l'informativa Privacy: https://www.exprivia.it/it/132/cookie-and-privacy-policy.php ** This e-mail and its attachments are intended for the addressee(s) only and are confidential and/or may contain legally privileged information. If you have received this message by mistake or are not one of the addressees above, you may take no action based on it, and you may not copy or show it to anyone; please reply to this e-mail and point out the error which has occurred. Click here to read your privacy notice: https://www.exprivia.it/it/132/cookie-and-privacy-policy.php

1 0

boost::asio::steady_timer only firing once
by Christopher Pisz 16 Jul '19

16 Jul '19

I am trying to perform a task on an interval and I made a POC using boost::asio::steady_timer. When I debug it, it only performs the callback once and does not fire again. I am not sure what I am doing wrong. Any suggestions? // DoMouseEvents.cpp : This file contains the 'main' function. Program execution begins and ends there. // #include <boost/asio.hpp> #include "boost/asio/deadline_timer.hpp" #include<boost/bind.hpp> #include <chrono> #include <iostream> class Pooper { boost::asio::io_context & m_ioContext; boost::asio::steady_timer m_timer; public: Pooper(boost::asio::io_context & ioContext) : m_ioContext(ioContext) , m_timer(boost::asio::steady_timer(ioContext)) { } void Run() { m_timer.expires_from_now(std::chrono::seconds(5)); m_timer.async_wait(boost::bind(&Pooper::OnTimerExpired, this, boost::asio::placeholders::error)); } void OnTimerExpired(const boost::system::error_code & error) { if (error.failed()) { std::cerr << "boost error: Failed" << std::endl; } std::cout << "Poop" << std::endl; try { // Move the mouse int x = 500; int y = 500; if (!::SetCursorPos(x, y)) { int errorCode = GetLastError(); std::cerr << "SetCursorPos error: " << errorCode << std::endl; } // Left button down x = 65536 * 500; y = 65536 * 500; ::mouse_event(MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTDOWN, x, y, NULL, NULL); // Left button up x = 65536 * 500; y = 65536 * 500; ::mouse_event(MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTUP, x, y, NULL, NULL); m_timer.expires_from_now(std::chrono::seconds(5)); m_timer.async_wait(boost::bind(&Pooper::OnTimerExpired, this, boost::asio::placeholders::error)); } catch (std::exception &) { std::cerr << "An exception occured." << std::endl; } } }; int main() { boost::asio::io_context ioContext; auto pooper = Pooper(ioContext); pooper.Run(); ioContext.run(); std::cerr << "Exited..." << std::endl; }

6 10

[multiprecision] Getting the best performance on windows for uint128_t etc
by Neill Clift 14 Jul '19

14 Jul '19

Hi, I develop a program for generating optimal addition chains. I normally use 64 bit integers but in order to attack some conjectures I compile up my program with boost using uint128_t. In order to get some functionality I need I used the backend access to limbs. For example I need population count/hamming weight/binary digit count. I did this like this: static LPTYPER bits(NTYPE n) /*++ Calculates the number of 1 bits in a number. --*/ { LPTYPER b = 0; std::size_t size = n.backend().size(); boost::multiprecision::limb_type* p = n.backend().limbs(); for (std::size_t i = 0; i < size; i++) { b += (LPTYPER)__popcnt64(p[i]); } return b; } I use the same sort of logic to calculate Floor(Log2(n)) (number of largest bit set), to clear the bottom say b bits of an integer. Is this a reasonable (though probably not idea) way to go? I noted that the limbs are 32 bits on Windows and this leads me to my second question. How can I get the internals of boost using bigger chunks like 64 bit? It seems I need a compiler supporting __int64. I have access to the intel compiler (19) and MSVC but neither seem to change this. I tried LLVM but that seemed quite slow. I may not have put enough effort into investigating LLVM up to this point. Various bit operations seem overly slow in boost. For example I use sequences like this: Control &= Control + 1; Mask = ((Control - 1) ^ Control) >> 1; Control |= Mask; These seem to be bottlenecks under boost. That sequence above is meant to generate masks that straddle the first run of zero bits in control so 1010100000111111_2 produces a mask of 11111111111_2. Thanks. Neill. Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

4 7

A question regarding gregorian week_iterator
by Bill Moo 12 Jul '19

12 Jul '19

I can’t understand what, if indeed anything, I am doing wrong here. Using boost 1.69 on Arch Linux I am trying to use a gregorian::week_iterator to iterate a gregorian date_period that has a length of 365 which produces this output: Starts 2018-07-10 Ends 2019-07-10 true false true 365 >From this code: boost::gregorian::date_period dp{ m_Start, m_Ends } ; BOOST_LOG(lg) << "Starts " << boost::gregorian::to_iso_extended_string(dp.begin()) << " Ends " << boost::gregorian::to_iso_extended_string(dp.end()) << " " << isYear << " " << isMonth << " " << isWeek << " " << dp.length() ; The following is the code I am using to iterate the date_period: for(boost::gregorian::week_iterator wi = dp.begin(); wi != dp.end(); ++wi) { items.push_back(formatParams(pi, (*wi))) ; } However, when this code executes it eventually fails with the following error: Year is out of valid range: 1400..9999 In my formatParams method the code generates the correct strings, but it doesn’t stop at Jun 2019 as I’d expect but continues to run out to 2375! I would appreciate some feedback on this as I have identical code that uses a gregorian::month_iterator and this generates the 12 items from the same date_period range as I’d expect. -- Bill

3 5

The out_ptr review is now over
by Zach Laine 11 Jul '19

11 Jul '19

Thanks to all that participated. A review result with be posted sometime in the next couple of weeks (the upcoming C++ standards meeting next week will delay it a bit). Zach

1 0

boost interprocess data structure operating when process killed
by 吴昊 09 Jul '19

09 Jul '19

Hello, as I haven’t read the source code deeply, I doubt about what will happen when boost interprocess is handling data structure such as map (e.g. rbtree rotating) while the process is killed (whether or not -9) or the machine is shutdown. Will the inner structure like the rbtree be broken ? Or will interprocess library detect this and fix it ?

2 1

[release] 1.71.0 closed for major changes
by Marshall Clow 04 Jul '19

04 Jul '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_71_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

1 0

out_ptr review is extended until Wednesday, July 10
by Zach Laine 26 Jun '19

26 Jun '19

We don't have enough reviews yet, so we're extending the review by two weeks. Please review this small and useful library! >From the original announcement: The formal review of JeanHeyd Meneide's out_ptr library starts Sunday, June 16th and ends on Wednesday, June 26th. out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). Online docs can be found here: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc The GitHub repository is available here: https://github.com/ThePhD/out_ptr Also, there is an associated standards proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html We encourage your participation in this review. At a minimum, please state: - Whether you believe the library should be accepted into Boost - Your name - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s)? * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? All issues discussed during this review will be tracked on the library's GitHub issue tracker at https://github.com/ThePhD/out_ptr/issues. Zach

1 0

out_ptr's formal review starts now!
by Zach Laine 25 Jun '19

25 Jun '19

Dear Boost community, The formal review of JeanHeyd Meneide's out_ptr library starts Sunday, June 16th and ends on Wednesday, June 26th. out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). Online docs can be found here: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc The GitHub repository is available here: https://github.com/ThePhD/out_ptr Also, there is an associated standards proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html We encourage your participation in this review. At a minimum, please state: - Whether you believe the library should be accepted into Boost - Your name - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s)? * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? All issues discussed during this review will be tracked on the library's GitHub issue tracker at https://github.com/ThePhD/out_ptr/issues. Regards, Zach Laine

3 4

[boost-users][asio] Make asio::strand using tcp::socket
by Fiver Dev 24 Jun '19

24 Jun '19

Hello everyone, How do I create this strand using the io_context of the socket in boost 1.70. asio::ip::tcp::socket socket; asio::io_context::strand strand( socket.get_executor().context() ); Thanks Tom

2 1

[boost-users] [compiler] Boost VC++ 14.2 test compiler
by Alex J 23 Jun '19

23 Jun '19

Hi, Does anybody know when boost will add VC++ 14.2 as a 'primary compiler tested' ?. At the moment they only have 14.1. Thanks

1 0

B2 release 4.0.0
by Rene Rivera 23 Jun '19

23 Jun '19

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. *Other changes in this release:* - Add support for using prebuilt OpenSSL. -- *Damian Jarek* - Define the riscv architecture feature. -- *Andreas Schwab* - Add ARM64 as a valid architecture for MSVC. -- *Marc Sweetgall* - Set coverage flags, from coverage feature, for gcc and clang. -- *Damian Jarek* - Add s390x CPU and support in gcc/clang. -- *Neale Ferguson* - Support importing pkg-config packages. -- *Dmitry Arkhipov* - Support for leak sanitizer. -- *Damian Jarek* - Fix missing /manifest option in clang-win to fix admin elevation for exes - with "update" in the name. -- *Peter Dimov* - Add freertos to os feature. -- *tee3* - Default parallel jobs (-jX) to the available CPU threads. -- *Rene Rivera* - Simpler coverage feature. -- *Hans Dembinski* - Better stacks for sanitizers. -- *James E. King III* *WARNING*: The default number of parallel jobs has changed in this release from "1" to the number of cores. There are circumstances when that default can be larger than the allocated cpu resources, for instance in some virtualized container installs. *Continuously tested on:* - Linux Clang 3.5, 3.6, 3.7, 3.8, 3.9, 4, 5, 6, 7, 8 - Linux GCC 4.7, 4.8, 4.9, 5, 6, 7, 8, 9 - macOS Xcode 8.3.3, 9.0, 9.0.1, 9.1, 9.2, 9.3, 9.3.1, 9.4, 9.4.1, 10.0, 10.1, 10.2, 10.2.1 - Windows MinGW 8.1.0 - Windows VS 2013, 2015, 2017, 2019 Documentation and more at <https://boostorg.github.io/build/> -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

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[boost] Does boost 1.70 officially support VS2019 14.2 compiler
by Alex J 20 Jun '19

20 Jun '19

Hi, Does boost 1.70 officially support VS2019 14.2 compiler ? Boost.org doesn't explicitly say that they does or doesn't support VS2019 14.2. Also they have 14.1 listed as a "primary compiler tested". Thanks Alex

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[release] 1.71.0 deadline for new libraries approaching
by Michael Caisse 19 Jun '19

19 Jun '19

One week from today master will closed for new libraries and breaking changes. Thanks, -- The Boost Release Team Boost Calendar with the release schedule: <http://www.boost.org/development/index.html>

1 0

How to set up user-config.jam properly?
by Robert Dailey 19 Jun '19

19 Jun '19

I am working on a user-config.jam file to build boost 1.70 against Android NDK r19. My jam file looks like this: ``` import os ; local ndk_cxx = [ os.environ CXX ] ; local ndk_ar = [ os.environ AR ] ; local ndk_ranlib = [ os.environ RANLIB ] ; local ndk_flags = [ os.environ CXXFLAGS ] ; using clang : x86 : "$(ndk_cxx)" : <cxxflags>"$(ndk_flags)" <archiver>"$(ndk_ar)" <ranlib>"$(ndk_ranlib)" <architecture>x86 <address-model>32 <binary-format>x86 <abi>x86 ; using clang : armeabi-v7a : "$(ndk_cxx)" : <cxxflags>"$(ndk_flags)" <archiver>"$(ndk_ar)" <ranlib>"$(ndk_ranlib)" <architecture>arm <address-model>32 <binary-format>elf <abi>aapcs ; ``` And my command line is: ``` ./bootstrap.sh --prefix=$INSTALL_DIR/boost || cat bootstrap.log ./b2 -j8 \ --without-python \ --without-test \ target-os=android \ toolset=clang-${ANDROID_ABI} \ variant=release \ threading=multi \ threadapi=pthread \ link=static \ runtime-link=shared \ install ``` When I run the commands above I get: ``` /_build/boost_1_70_0/tools/build/src/build/feature.jam:314: in implied-subfeature from module feature error: "armeabi" is not a known subfeature value of <toolset>clang /_build/boost_1_70_0/tools/build/src/build/feature.jam:497: in feature.validate-value-string from module feature /_build/boost_1_70_0/tools/build/src/build/property.jam:341: in validate1 from module property /_build/boost_1_70_0/tools/build/src/build/property.jam:367: in validate from module property /_build/boost_1_70_0/tools/build/src/build/property.jam:376: in property.validate-property-sets from module property /_build/boost_1_70_0/tools/build/src/build/toolset.jam:187: in toolset.flags from module toolset /_build/boost_1_70_0/tools/build/src/tools/common.jam:447: in common.handle-options from module common /_build/boost_1_70_0/tools/build/src/tools/clang-linux.jam:62: in clang-linux.init from module clang-linux /_build/boost_1_70_0/tools/build/src/build/toolset.jam:44: in toolset.using from module toolset /_build/boost_1_70_0/tools/build/src/tools/clang.jam:33: in clang.init from module clang /_build/boost_1_70_0/tools/build/src/build/toolset.jam:44: in toolset.using from module toolset /_build/boost_1_70_0/tools/build/src/build/project.jam:1104: in using from module project-rules /home/build/user-config.jam:28: in modules.load from module user-config /_build/boost_1_70_0/tools/build/src/build-system.jam:255: in load-config from module build-system /_build/boost_1_70_0/tools/build/src/build-system.jam:453: in load-configuration-files from module build-system /_build/boost_1_70_0/tools/build/src/build-system.jam:607: in load from module build-system /_build/boost_1_70_0/tools/build/src/kernel/modules.jam:295: in import from module modules /_build/boost_1_70_0/tools/build/src/kernel/bootstrap.jam:139: in boost-build from module /_build/boost_1_70_0/boost-build.jam:17: in module scope from module ``` The value of `ANDROID_ABI` is either `x86` or `armeabi-v7a`. What I'm not sure about is this syntax in the JAM file: ``` using <platform> : <subfeature> : <toolchain> ``` Why is this failing? Can someone explain this strange syntax in the JAM file? What is "subfeature" for and what values does it accept? How does this map to the command line arguments? How should I best set up my user config jam file for providing different build parameters per architecture in a cross-compilation setting (building for Android)?

1 1

Re: [Boost-users] [CMake] Specifying name of library file on CMake command line?
by Osman Zakir 17 Jun '19

17 Jun '19

From: Kyle Edwards <kyle.edwards(a)kitware.com> Sent: Monday, June 17, 2019 6:49 PM To: Osman Zakir; cmake(a)cmake.org Subject: Re: [CMake] Specifying name of library file on CMake command line? On Mon, 2019-06-17 at 13:47 +0000, Osman Zakir wrote: >> I want to know how to specify the name of a library I file I want to >> link against. How do I do this? I wanted to build a library with a >> static runtime and static libs; it requires linking against a Boost >> library which I did build with static runtime but when I tried to >> build it, I had linker errors because the dynamic version of the >> library was used instead of the static one. I want to somehow make >> it use the static one. So yeah, how do I do this? Is there a way? >Are you using the FindBoost module? >https://cmake.org/cmake/help/v3.14/module/FindBoost.html >Kyle Yes, I'm using that module. I didn't make any changes to it; it came with the third-party library I'm trying to build.

2 2

Boost.Units: unit type for dBm
by Carel Combrink 17 Jun '19

17 Jun '19

Hi, I have a system that uses dBm to indicate Signal Amplitude, how do I create a type using Boost.Units for this? At the moment I am not concerned about any type of conversions between power and this ratio. Any help will be appreciated. I am already using boost.unit successfully for other units and conversions with the help from the mailing list. I want to now define the correct strong type for this type for consistency. Regards, Carel

2 1

Building Boost.Python for a custom Python installation
by Evan Driscoll 14 Jun '19

14 Jun '19

I have a build of Python I made that was installed (--prefix) at ~/python-3.5.2-asan/. I want to build Boost.Python against it. I have Boost 1.70.0. I have tried a variety of permutations of passing various --with-python options and such to both bootstrap and b2 with no success. Perhaps the closest I've gotten is ./bootstrap.sh --prefix=$HOME/boost-1.70.0/ --with-python=$HOME/python-3.5.2-asan/bin/python3.5 python-debugging=on ./b2 --with-python python-debugging=on -d+2 -j8 cxxflags=-fsanitize=address cflags=-fsanitize=address but with those commands compilation fails because it is looking for include files in ...../include/python3.5/ instead of ..../include/python3.5dm While I'm at it, I had to add cflags and cxxflags explicitly instead of doing what some documentation [1] said to, because: ./b2 --with-python python-debugging=on -d+2 -j8 address-sanitizer=1 /home/evan/Downloads/boost_1_70_0/tools/build/src/build/feature.jam:327: in validate-feature from module feature error: unknown feature "<address-sanitizer>" [1] https://boostorg.github.io/build/manual/develop/index.html#_sanitizers Evan

1 0

[Process] Zombie Processes left behind
by Ryan Ruhge 05 Jun '19

05 Jun '19

Boost Team: We are trying to use boost process to have an always running process spawn child processes in a fire and forget manner (don't wait or block on the process that was just spawned). The issue we are running into is that the child processes become zombie processes when finished until the parent process completes. However in our system the parent process is never intended to complete, it is always running and listening. We have provided code snippets which give a simple example of the symptom we are experiencing. It's an infinite loop (imitating our always running process) that spawns processes that run and then become zombies instead of finishing (I included a sleep so it doesn't spawn processes too quickly). Please advise on whether there is something else we can do, if we are using child or spawn wrong, or if we are using boost process in a manner that it is not intended to be used. Thanks, Ryan Ruhge #include <boost/process.hpp> using namespace std; int main() { while (true) { boost::process::spawn("sleep 10"); sleep(5); } } #include <boost/process.hpp> using namespace std; int main() { while (true) { boost::process::child childProcess("sleep 10"); childProcess.detach(); sleep(5); } }

2 1

Downloads of boost from Bintray.com are temporarily unavailable
by Marshall Clow 30 May '19

30 May '19

Apparently, Boost is being downloaded over 6000 times/day from Bintray, and we've reached the limits of their bandwidth for the month. We're trying to get them to increase our quota (and see if there's someone who is downloading boost over and over again), but at the present time, downloads from bintray are being rejected. Hopefully this will be a temporary situation. -- Marshall (boost release manager)

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Re: [Boost-users] catmull_rom splines
by Nick Thompson 30 May '19

30 May '19

Yes, the Catmull-Rom curve is confusing for scientific application developers because it *creates* a parametrization. For example, if you solved by stepper an ODE y' = f(t,y) and got a solution skeleton {t_i, y_i}, the Catmull-Rom curve *wouldn't accept the time points t_i*. It's only interested in the y_i. Since the Catmull-Rom curve is used in computer graphics, you can kinda see why those guys don't care what the parametrization is. I'm currently working on extending the barycentric rational interpolator into higher dimensions; mathematically it's trivial but getting the interface right is (as always) the real problem. Nick ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Thursday, May 30, 2019 8:52 AM, Giorgino R <giorginor21(a)gmail.com> wrote: > Dear Nick/all, > > That was my bad. > > I though that the parametrisation should be in the range [0-1] or [x_min-x_max]. I debugged my program and I saw that Catmull-Rom class internally change the parametrisation from 0 to m_max_s (for normal range 0 -1). Actually, it is explicitly mentioned in the documentation, as well. For some reason, I didn't interpret it properly. I attach my normal spline that now look as expected. > > Apologies for the trouble. It's because I have never had any previous experience with these type of splines. > > Many thanks > Giorgio > > On Thu, May 30, 2019 at 11:07 AM Giorgino R <giorginor21(a)gmail.com> wrote: > >> Dear Nick, >> >> Many thanks for your prompt reply along with your valuable suggestions. >> >> I have now added two ghost points at each end as you described; however, the curve looks (see the attached) more disappointing (always for my objectives :) ). >> To clarify, what I am trying to achieve is to get a (interpolation) line that passes through all the knots/points. Then, for a set of discrete x values (within the space of the line) I want to evaluate the corresponding points and pass them to a boost::linestring. I tried also with both [Cubic B-spline interpolation](https://www.boost.org/doc/libs/1_70_0/libs/math/doc/html/mat… and [Barycentric Rational Interpolation](https://www.boost.org/doc/libs/1_70_0/libs/math/doc/html/mat…. However, my sample points are not equally spaced and non-monotonic (x values). Therefore, I found that Catmull-Rom may be of better use here. >> >> The other issue that is unclear to myself is that the evaluation of a Catmull-Rom spline looks dependent on the parametrisation (see the two images in my first email), as well. >> >> Since in my application I am going to use Boost geometry, I would really like to find a solution on how to interpolate such data point sets with functionality available in Boost. >> >> Once again, many thanks for your support. >> >> Giorgio >> >> On Wed, May 29, 2019 at 6:32 PM Nick Thompson via Boost-users <boost-users(a)lists.boost.org> wrote: >> >>> Hi Giorgino, >>> >>> The strange behavior at the end of the Catmull-Rom splines is a deficiency of the method. However, we are fortunate that this is not a big deficiency. This is because the Catmull-Rom splines are interpolated by functions of compact support, so a point can influence at most four segments (only two, if the point is on the boundary). Looking at your images, I personally don't think they look bad. But presumably since you are writing this, you want better! >>> >>> I would recommend adding two ghost points. Draw a line between point 0 and point 1, and put the ghost point "in the mirror", i.e., place it where point 1 would appear if a mirror sat in the plane passing through P0 and orthogonal to the line joining point zero and point one. You might contend that this is an arbitrary choice, and it is! But the compact support of the basis functions means that the decision is not super important, and this choice will at least give reasonable-looking tangent vectors. >>> >>> Nick >>> >>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ >>> On Wednesday, May 29, 2019 12:08 PM, Giorgino R via Boost-users <boost-users(a)lists.boost.org> wrote: >>> >>>> Hi all, >>>> >>>> I am trying to interpolate some data with a catmull_rom spline available in boost math (interpolation). However, the resulting spline has a strange behavior; especially, at its ends (see the attached image). >>>> Just out of curiosity, I also tried to normalise my data to [0-1] range. However, the line has had even worse behavior (see the attached image). >>>> Below, the c++ code segment of the interpolation is depicted: >>>> >>>> std::vector<std::array<double, 2>> points_intr(16); >>>> >>>> points_intr[0] = { 1.263270, 0.774614 }; >>>> points_intr[1] = { 1.876, 2.480 }; >>>> points_intr[2] = { 1.651110, 4.550 }; >>>> points_intr[3] = { 1.426340, 5.688 }; >>>> points_intr[4] = { 1.429, 7.054 }; >>>> points_intr[5] = { 2.073220, 8.377020 }; >>>> points_intr[6] = { 3.910, 9.140 }; >>>> points_intr[7] = { 6.430, 9.537 }; >>>> points_intr[8] = { 8.950, 9.859 }; >>>> points_intr[9] = { 11.470, 10.317 }; >>>> points_intr[10] = { 12.730, 10.6456 }; >>>> points_intr[11] = { 13.990, 11.0741 }; >>>> points_intr[12] = { 15.335, 11.6928 }; >>>> points_intr[13] = { 16.680, 12.5661 }; >>>> points_intr[14] = { 18.3538, 14.830 }; >>>> points_intr[15] = { 18.700, 16.056 }; >>>> >>>> bm::catmull_rom<std::array<double, 2>> >>>> interpolator_cr(std::move(points_intr)); >>>> >>>> std::vector<double> x_linspace_cr(100); >>>> std::vector<std::array<double, 2>> inter_points(100); >>>> linspace(1.263270, 18.700, 100, x_linspace_cr); // evaluation points along the line >>>> >>>> for (std::size_t i{0}; i < x_linspace_cr.size(); ++i) >>>> { >>>> inter_points[i] = interpolator_cr(x_linspace_cr[i]); >>>> } >>>> >>>> Should I have to add additional (ghost) points at both ends? If yes, is there any optimum way to calculate where exactly to poisition these points? I understand if I get the derivatives at both end I can calculate a straight line that the additional points should lie within. However, how should I calculate the distance from the end points? >>>> >>>> I hope I am not doing anything fundamentally wrong. Any help would be much appreciated. >>>> >>>> Many thanks! >>> >>> _______________________________________________ >>> Boost-users mailing list >>> Boost-users(a)lists.boost.org >>> https://lists.boost.org/mailman/listinfo.cgi/boost-users

1 0

catmull_rom splines
by Giorgino R 29 May '19

29 May '19

Hi all, I am trying to interpolate some data with a catmull_rom spline available in boost math (interpolation). However, the resulting spline has a strange behavior; especially, at its ends (see the attached image). Just out of curiosity, I also tried to normalise my data to [0-1] range. However, the line has had even worse behavior (see the attached image). Below, the c++ code segment of the interpolation is depicted: std::vector<std::array<double, 2>> points_intr(16); points_intr[0] = { 1.263270, 0.774614 }; points_intr[1] = { 1.876, 2.480 }; points_intr[2] = { 1.651110, 4.550 }; points_intr[3] = { 1.426340, 5.688 }; points_intr[4] = { 1.429, 7.054 }; points_intr[5] = { 2.073220, 8.377020 }; points_intr[6] = { 3.910, 9.140 }; points_intr[7] = { 6.430, 9.537 }; points_intr[8] = { 8.950, 9.859 }; points_intr[9] = { 11.470, 10.317 }; points_intr[10] = { 12.730, 10.6456 }; points_intr[11] = { 13.990, 11.0741 }; points_intr[12] = { 15.335, 11.6928 }; points_intr[13] = { 16.680, 12.5661 }; points_intr[14] = { 18.3538, 14.830 }; points_intr[15] = { 18.700, 16.056 }; bm::catmull_rom<std::array<double, 2>> interpolator_cr(std::move(points_intr)); std::vector<double> x_linspace_cr(100); std::vector<std::array<double, 2>> inter_points(100); linspace(1.263270, 18.700, 100, x_linspace_cr); // evaluation points along the line for (std::size_t i{0}; i < x_linspace_cr.size(); ++i) { inter_points[i] = interpolator_cr(x_linspace_cr[i]); } Should I have to add additional (ghost) points at both ends? If yes, is there any optimum way to calculate where exactly to poisition these points? I understand if I get the derivatives at both end I can calculate a straight line that the additional points should lie within. However, how should I calculate the distance from the end points? I hope I am not doing anything fundamentally wrong. Any help would be much appreciated. Many thanks!

2 1

bug or documentation missing boost posix_time time_duration not_a_date_time
by Erik Thiele 27 May '19

27 May '19

hi please compile this program: #include <boost/date_time/posix_time/ptime.hpp> #include <iostream> #include <vector> using namespace boost::posix_time; using namespace std; #define x(v) cout << #v << " : " << (v) << '\n'; int main(int argc, char *argv[]) { time_duration a(not_a_date_time); time_duration b; x(a<b); x(a>b); x(a<=b); x(a>=b); x(b<a); x(b>a); x(b<=a); x(b>=a); x(a==b); x(b==a); x(a.is_special()); x(b.is_special()); vector<time_duration> v0, v1; v0.push_back(time_duration()); v0.push_back(time_duration(not_a_date_time)); sort(v0.begin(), v0.end()); v1.push_back(time_duration(not_a_date_time)); v1.push_back(time_duration()); sort(v1.begin(), v1.end()); x(v0==v1); return 0; } the output is: a<b : 0 a>b : 0 a<=b : 1 a>=b : 1 b<a : 0 b>a : 0 b<=a : 1 b>=a : 1 a==b : 0 b==a : 0 a.is_special() : 1 b.is_special() : 0 v0==v1 : 0 if the time_duration datatype is a complete partial order which is for example needed for it to be able to be sorted, then the above output is partly illegal: if not a<b and not b<a then must be a=b. but this is not the case. if a<=b and b<=a then must be a=b. but this is not the case. so as expected the two vectors v0 and v1 are not equal after being sorted even though they certainly should be! i do not understand why time_duration is behaving in such a strange way here. I am using time_duration(not_a_date_time) as a SQL-NULL value just like i am using date(not_a_date_time) and ptime(not_a_date_time) as SQL-NULL values. obviously I should not use time_duration(not_a_date_time). maybe this is the reason why time_duration() != time_duration(not_a_date_time)? I don't understand the design here. for example date()==date(not_a_date_time) and also ptime()==ptime(not_a_date_time) but not with time_duration. why??? why is there no documentation that time_duration is not a complete partial order and thus not sortable - at least when using not_a_date_time? cya erik

2 5

[Boost.Build] configure.builds and check-target-builds always build in debug mode
by David Callu 25 May '19

25 May '19

Hi, I try to add icu support in boost conan package, but on windows with msvc, the build never use icu. During icu detection in boost.locale, the has_icu.exe never build because configure.builds try to build in debug mode when I use property "variant=release" in b2 command line. I can see that in config.log written by b2 during build : b2 use icuucd.lib and icuind.lib instead of icuuc.lib and icuin.lib. So icu is not correctly detected, and so never used. If I bypass the has_icu test, boost locale build fine and have icu backend as expected. This behaviors only fail builds that use different library in release and debug mode, like icu build with msvc. Is it the correct behaviors ? - If yes this is a bad news for library with different library name in release and debug mode. - If no ... houston, we have a problem Best regards David

1 0

[asio] example link dead
by Stephan Menzel 21 May '19

21 May '19

This is just a quick heads up. The website link to a file example in asio: https://www.boost.org/doc/libs/1_70_0/doc/html/boost_asio/example/cpp11/non… ... appears to be dead. 404. HTH... Stephan

3 2

Re: [Boost-users] linker error boost with 1.69 and 1.70
by Danny K 21 May '19

21 May '19

I figured out my problem so please disregard my question. My problem was that zlib and bzip2 support was not being included. I developed a perl script that builds everything for me for Windows & Linux and somehow when the Linux script builds 1.69 or 1.70, it turns off zlib and bzip2 support. Not sure the cause but taking the command my perl script executes and running it the shell outside of perl, boost builds with the proper support for zlib/bzip2 in iostreams. Not sure what the change would be but I have a workaround. wr, Danny

1 0

linker error boost with 1.69 and 1.70
by Danny K 20 May '19

20 May '19

So I have been using boost for awhile. I compile boost the same way for all the versions and have been since 1.48. My platforms are CentOS 6 & 7 and Windows 10 vs2017. My code has compiled on all 3 platforms with Boost without a problem. My current version is 1.66 and I wanted to upgrade to 1.69. Under Windows, I build 1.69 with ZLIB & BZIP and my applications have no problems. I use zlib & bzip in the IOstreams library to read & write compressed files. So I built 1.69 under Linux the same way as I always have but I am now getting a linker error that I don't understand and I am stuck. The error starts with: API_utiltyFunctions.cpp:(.text+0x154): undefined reference to `boost::iostreams::detail::zlib_base::before(char const*&, char const*, char*&, char*)' API_utiltyFunctions.cpp:(.text+0x15b): undefined reference to `boost::iostreams::zlib::sync_flush' API_utiltyFunctions.cpp:(.text+0x165): undefined reference to `boost::iostreams::detail::zlib_base::xinflate(int)' API_utiltyFunctions.cpp:(.text+0x177): undefined reference to `boost::iostreams::detail::zlib_base::after(char const*&, char*&, bool)' API_utiltyFunctions.cpp:(.text+0x17e): undefined reference to `boost::iostreams::zlib_error::check(int)' API_utiltyFunctions.cpp:(.text+0x185): undefined reference to `boost::iostreams::zlib::stream_end' The boost portion of my linker line is: -L[ path to boost 1.69] \ -lboost_random-1_69 \ -lboost_program_options-1_69 \ -lboost_date_time-1_69 \ -lboost_chrono-1_69 \ -lboost_regex-1_69 \ -lboost_thread-1_69 \ -lboost_exception-1_69 \ -lboost_filesystem-1_69 \ -lboost_system-1_69 \ -lboost_iostreams-1_69 -lrt -lbz2 -lz -lm Any help would be appreciate. Weirdly if I revert back to boost 1.66, I don't have a problem. I also tested this compilation against boost 1.70 and I get the same problem. I do compile boost statically with shared runtime libraries and threads. Respectfully, Danny K

1 0

[variant2] Acceptance conditions met - Targeted for 1.71.0
by Michael Caisse 16 May '19

16 May '19

Peter Dimov has updated the Variant2 library based on review acceptance criteria. I have reviewed the changes and "OK" Variant2 to be included as a Boost library. My understanding is that Peter is targeting Variant2 to be available in the 1.71.0 release. Congratulations Peter! Thank you for your quick work in updating the library based on the review feedback. -- Michael Caisse Ciere Consulting ciere.com

1 0

Building boost 1_70_0 with PGI 18.5 on CentOS 7
by Christopher Harrop - NOAA Affiliate 16 May '19

16 May '19

Hi, I am having trouble building Boost 1_70_0 with PGI 18.5 on a Linux CentOS 7 system, and I am wondering if anyone has suggestions about how to get it working. I spent some time searching online for answers, but didn’t find anything recent that applied to my problem. I am a novice with boost, and so am not sure where to start digging for solutions. I have no issues with GCC or Intel compilers. My procedure, after I untar and cd into the boost directory, is as follows: ./bootstrap.sh --with-toolset=pgi —prefix=/path/to/install/boost export BUILD_TYPE=complete export LIBRARY_NAME=versioned export LIBRARY_TARGETS=shared,static ./b2 -j 12 install --build-type=${BUILD_TYPE} --layout=${LIBRARY_NAME} --target=${LIBRARY_TARGETS} This procedure appears to work fine for the intel-linux and gcc toolsets. But, for pgi, I get this: ==================================== +./bootstrap.sh --with-toolset=pgi --prefix=/path/to/install/boost Building Boost.Build engine with toolset pgi... tools/build/src/engine/bin.linuxx86_64/b2 Detecting Python version... 2.7 Detecting Python root... /usr Unicode/ICU support for Boost.Regex?... /usr Generating Boost.Build configuration in project-config.jam for pgi... 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://www.boost.org/more/getting_started/unix-variants.html - Boost.Build documentation: http://www.boost.org/build/ + export BUILD_TYPE=complete + BUILD_TYPE=complete + export LIBRARY_NAME=versioned + LIBRARY_NAME=versioned + export LIBRARY_TARGETS=shared,static + LIBRARY_TARGETS=shared,static + ./b2 -j 12 install --build-type=complete --layout=versioned --target=shared,static Performing configuration checks - default address-model : none - default architecture : none /scratch4/BMC/gsd-hpcs/Christopher.W.Harrop/bass-develop/build/boost/1.70.0/pgi/18.5/tools/build/src/tools/common.jam:977: in toolset-tag *** argument error * rule numbers.less ( n1 n2 ) * called with: ( 4 ) * missing argument n2 ==================================== Based on some suggestions I found online from others having similar errors, I edited tools/build/src/tools/common.jam to comment out these lines (977-980): # From GCC 5, versioning changes and minor becomes patch # if $(tag) = gcc && [ numbers.less 4 $(version[1]) ] # { # version = $(version[1]) ; # } This results in the following failure, which I’ve truncated because it’s really long: ==================================== + ./bootstrap.sh --with-toolset=pgi --prefix=/scratch4/BMC/gsd-hpcs/Christopher.W.Harrop/bass-develop/opt/boost/1.70.0/pgi/18.5 Building Boost.Build engine with toolset pgi... tools/build/src/engine/bin.linuxx86_64/b2 Detecting Python version... 2.7 Detecting Python root... /usr Unicode/ICU support for Boost.Regex?... /usr Generating Boost.Build configuration in project-config.jam for pgi... 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://www.boost.org/more/getting_started/unix-variants.html - Boost.Build documentation: http://www.boost.org/build/ + export BUILD_TYPE=complete + BUILD_TYPE=complete + export LIBRARY_NAME=versioned + LIBRARY_NAME=versioned + export LIBRARY_TARGETS=shared,static + LIBRARY_TARGETS=shared,static + ./b2 -j 12 install --build-type=complete --layout=versioned --target=shared,static Performing configuration checks - default address-model : none - default architecture : none 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 next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>elf <threading>multi <toolset>qcc not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>pe <threading>multi <toolset>msvc not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>o32 <address-model>32 <architecture>mips1 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>o32 <address-model>32 <architecture>mips1 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>n64 <address-model>64 <architecture>mips1 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>n64 <address-model>64 <architecture>mips1 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>xcoff <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>xcoff <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>xcoff <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>xcoff <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32_64 <architecture>power <binary-format>mach-o <threading>multi not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>elf <threading>multi <toolset>intel not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang-win not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>intel not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>msvc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>intel not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>intel not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang-win not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>intel not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>msvc not matched next alternative: required properties: <abi>x32 <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>x32 <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>x32 <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>intel not matched next alternative: required properties: <abi>sysv <address-model>32_64 <architecture>x86 <binary-format>mach-o <threading>multi not matched next alternative: required properties: <abi>sysv <architecture>combined <binary-format>mach-o <threading>multi not matched - C++11 mutex : no - lockfree boost::atomic_flag : no - Boost.Config Feature Check: cxx11_auto_declarations : no - Boost.Config Feature Check: cxx11_constexpr : no - Boost.Config Feature Check: cxx11_defaulted_functions : no - Boost.Config Feature Check: cxx11_final : no - Boost.Config Feature Check: cxx11_hdr_mutex : no - Boost.Config Feature Check: cxx11_hdr_tuple : no - Boost.Config Feature Check: cxx11_lambdas : no - Boost.Config Feature Check: cxx11_noexcept : no - Boost.Config Feature Check: cxx11_nullptr : no - Boost.Config Feature Check: cxx11_rvalue_references : no - Boost.Config Feature Check: cxx11_template_aliases : no - Boost.Config Feature Check: cxx11_thread_local : no - Boost.Config Feature Check: cxx11_variadic_templates : no - has_icu builds : no warning: Graph library does not contain MPI-based parallel components. note: to enable them, add "using mpi ;" to your user-config.jam - zlib : no - bzip2 : no - lzma : no - zstd : no - iconv (libc) : no - iconv (separate) : no - icu : no - icu (lib64) : no - Boost.Locale needs either iconv or ICU library to be built. - Boost.Locale needs either iconv or ICU library to be built. - native-atomic-int32-supported : no - native-syslog-supported : no - pthread-supports-robust-mutexes : no - x86 : no - arm : no - mips1 : no - power : no - sparc : no - gcc visibility : no - long double support : no warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. - libbacktrace builds : no - addr2line builds : no - WinDbg builds : no - WinDbgCached builds : no - BOOST_COMP_GNUC >= 4.3.0 : no error: No best alternative for libs/context/build/asm_sources ### similar messages to the above repeat several times and I’ve left it out for clarity and length, then output continues below ### Component configuration: - atomic : building - chrono : building - container : building - context : building - contract : building - coroutine : building - date_time : building - exception : building - fiber : building - filesystem : building - graph : building - graph_parallel : building - headers : building - iostreams : building - locale : building - log : building - math : building - mpi : building - program_options : building - python : building - random : building - regex : building - serialization : building - stacktrace : building - system : building - test : building - thread : building - timer : building - type_erasure : building - wave : building ...patience... ...patience... ...patience... ...patience... ...patience... ...found 45809 targets... ...updating 17951 targets... gcc.compile.c++ bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/posix_api.o /bin/sh: line 1: -fvisibility-inlines-hidden: command not found -fvisibility-inlines-hidden -fPIC -pthread -O0 -fno-inline -Wall -g -fvisibility=hidden -DBOOST_ALL_NO_LIB=1 -DBOOST_REGEX_DYN_LINK=1 -I"." -c -o "bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/posix_api.o" "libs/regex/build/../src/posix_api.cpp" ...failed gcc.compile.c++ bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/posix_api.o... gcc.compile.c++ bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/c_regex_traits.o /bin/sh: line 1: -fvisibility-inlines-hidden: command not found -fvisibility-inlines-hidden -fPIC -pthread -O0 -fno-inline -Wall -g -fvisibility=hidden -DBOOST_ALL_NO_LIB=1 -DBOOST_REGEX_DYN_LINK=1 -I"." -c -o "bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/c_regex_traits.o" "libs/regex/build/../src/c_regex_traits.cpp" ...failed gcc.compile.c++ bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/c_regex_traits.o... gcc.compile.c++ bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/instances.o /bin/sh: line 1: -fvisibility-inlines-hidden: command not found -fvisibility-inlines-hidden -fPIC -pthread -O0 -fno-inline -Wall -g -fvisibility=hidden -DBOOST_ALL_NO_LIB=1 -DBOOST_REGEX_DYN_LINK=1 -I"." -c -o "bin.v2/libs/regex/build/gcc/debug/threading-multi/visibility-hidden/instances.o" "libs/regex/build/../src/instances.cpp" ==================================== Chris ----------------------------------------------------------------------------------------------------------- Christopher W. Harrop email: christopher.w.harrop(a)noaa.gov <mailto:christopher.w.harrop@noaa.gov> Global Systems Division voice: (303) 497-6808 <tel:%28303%29%20497-6808> NOAA Earth System Research Laboratory fax: (303) 497-7259 <tel:%28303%29%20497-7259> 325 Broadway R/GSD2 Boulder, CO 80303

3 4

[stacktrace]stacktrace print nothing on x86.
by Hao Jiang 16 May '19

16 May '19

Hello everyone, I found boost::stacktrace print no information on my machine in RELEASE mode when target is x86, i.e. the size of stacktrace is zero. But if target switched to x64, stacktrace worked fine. Is anyone knows the reason? OS: Windows 7(64) Compiler: MSVC 14 Boost ver. :1.67/1.69 Stacktrace config: BOOST_STACKTRACE_USE_WINDBG(_CACHED) Thanks, Hao Jiang.

1 0

Boost Graph write_grahml - wrong source- and target-ID's in edge of XML-File
by lila 13 May '19

13 May '19

Hi there, I want to create an xml-file out of my Graph... So I'm using the write_graphml Function with dynamic_properties. Everything is fine, I get a file, but there are wrong source- and target- ID's in the edge structs ... Here an example: <node id="n1"> <data key="key0">vertex_7</data> <data key="key2">bf88aa63-bff1-5c04-8daf-37a5e31981f6</data> <data key="key6">12.5</data> <data key="key7">7.5</data> </node> <edge id="e1" source="n1" target="n2"> <data key="key1">edge_4_5</data> <data key="key3">26c512cb-46d8-5eb5-8021-2aac9f492227</data> <data key="key4">45844430-f1ea-5355-b7ce-eb566fe89256</data> <data key="key5">ecac63d6-e531-5ce8-9578-13cb63d040de</data> </edge> In the edge there is the wrong source-ID - it should be the ID of Vertex 4 (source="n0") not 7 (source="n1") My Graph: struct vertex { float x; float y; string name; string uuid; }; struct edge { string source_v_uuid; //startpoint uuid string target_v_uuid; //endpoint uuid string name; // name - edge_from_src-Vertex_to_dest-Vertex string uuid; }; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, vertex, edge> myGraph; And my Properties: boost::dynamic_properties dyn_p; // fill vertex properties dyn_p.property("name", get(&vertex::name, graph)); dyn_p.property("x-value", get(&vertex::x, graph)); dyn_p.property("y-value", get(&vertex::y, graph)); dyn_p.property("uuid", get(&vertex::uuid, graph)); // fill edge properties dyn_p.property("name", get(&edge::name, graph)); dyn_p.property("v-src-uuid", get(&edge::source_v_uuid, graph)); dyn_p.property("v-dest-uuid", get(&edge::source_v_uuid, graph)); dyn_p.property("uuid", get(&edge::uuid, graph)); write_graphml(ofs, graph, dyn_p, true); I tried to create a property map by myself to set the UUID as the (vertex (source/target)) -ID's, but that changed nothing, there are still wrong source- and target- ID's in the edge struct. auto map = get(&vertex2::uuid, graph); write_graphml(ofs, graph, map, dyn_p, true); Can anybody help me? Or even give me a hint to figure out what is going wrong? -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

1 0

[variant2] Review Results
by Michael Caisse 11 May '19

11 May '19

First, I would like to apologize to Peter and the those who took time to review Boost.Variant2 for the slow turn-around of a result. Thank you Peter for producing and submitting such a high-quality library for review. The code has been a pleasure to read and review. Thank you to the reviewers! Your participation in the process is what makes Boost libraries high-quality. I personally appreciate the time and effort that each of you have put into this review. ------------- Result ------------- Boost.Variant2 will be ACCEPTED after the following changes are made. An additional review will not be required. - The library will implement the strong guarantee: - If all alternatives have nothrow move, single buffer - else, double buffer - Improved documentation: - Addition of a tutorial - Addition of design motivation - Peter has indicated that triviality propagation will come in a future version. The initial Boost release need not support triviality propagation. - Expected will not be included but may be submitted for review at another time. ---------------- Review Verdicts ---------------- The following people provided reviews. Reject ---------- Andrezj Krzemienski Antony Polukhin Jan Herrmann Accept ---------- Emil Dotchevski Gavin Lambert Phil Endecott Conditionally Accept -------- Bjorn Reese Andrey Semashev Damian Jarek Niall Douglas Andrezj and Antony’s rejections were based on not having a valueless-by-exception state. Neither saw the selected design space worth considering and each believed the trade-off was dangerous for users. The Conditional Acceptance reviews voiced the following: - Strong preference for the strong guarantee (and therefore no need to provide “surprising” behaviour for the state after an exception.) - Improved documentation containing both tutorial and motivation sections. - Triviality propagation of the variant types. - Accepted without expected being contained. -------------- Some Thoughts -------------- There was a good amount of healthy discussion on the Developer Mail List concerning Variant2. I want to thank all of the participants for engaging with civility and keeping to the technical merits despite the galvanized opinions concerning valueless-by-exception and the basic exception guarantee. Over the past couple weeks I have re-read all of the discussion threads 3 or 4 times. While some people didn’t find value in the exchanges, this level of engagement about design trade-offs is one of the attributes that sets Boost reviews apart. They are not merely reviews discussing the quality of implementation but also the intricacies of design choices within the constraints and consistency of the language. When reviewers articulate their opinions the entire community learns and grows. The trade-offs that Peter made seem dangerous to some yet the exact correct formulation for others. There are even standard library implementers that don’t agree with std::variant’s valueless-by-exception. A high-quality variant that provides the strong exception guarantee is a type that has been missing from the programmer toolbox. Variant2 provides this. I will make an additional announcement to the community when the conditions for acceptance have been met. Thank you all for making Boost better! michael -- Michael Caisse Ciere Consulting ciere.com -- Michael Caisse Ciere Consulting ciere.com

1 0

filesystem::path crash on Windows when dealing with umlauts ( üëï )
by Gonzalo Garramuño 09 May '19

09 May '19

I am getting a crash on Windows when passing a path that contains umlauts (like sampëüö ) to the path constructor. I tried boost 1.69 and boost 1.60. Here's the code I am using: namespace fs = boost::filesystem; const char* tmp = setlocale(LC_ALL, N_("")); // Create and install global locale std::locale::global(boost::locale::generator().generate( N_("") )); // Make boost.filesystem use it fs::path::imbue(std::locale()); if ( !tmp ) tmp = setlocale( LC_ALL, NULL ); std::string program = argv[0]; fs::path file = fs::path( program ); // CRASH -- Gonzalo Garramuño

3 2

A property_tree like structure where key is also value?
by Jeanette C. 05 May '19

05 May '19

Hey hey, I need a hirarchical data representation in my program, which is well modelled by boost.property_tree, but my keys will also be my values. The tree will have a fixed depth, all keys/values are std::string and I expect maybe a few hundred leaves and maybe a hundred or so nodes in between. Is it worth looking for a different structure at all, considering that the program is designed for desktop systems? If so: is there another Boost library that would serve me better? Best wishes and thanks for any tips, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * SoundCloud: https://soundcloud.com/jeanette_c * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * GitHub: https://github.com/jeanette-c * Twitter: https://twitter.com/jeanette_c_s I'm not that innocent... <3 (Britney Spears)

1 0

[Boost.Asio coroutines] Question about HTTPServer4 examples
by daniil＠daniil.it 01 May '19

01 May '19

1 1

Using Boost 1.63 and 1.66 together with GNU unique global objects
by Jamie Jason 30 Apr '19

30 Apr '19

Apologies if this is a newbie question, but I have done my best to search Google, etc., and haven't been able to find a solution. The project I am working on uses Boost 1.63 statically linked and a third-party shared library that uses Boost 1.66 statically linked on CentOS 7. For reasons that are beyond my control, these are the versions that must be used. I am running into a problem with g++ 4.5.8 and the GNU extension to ELF for unique global symbols. Take as example the function get_netdb_category() in boost/asio/impl/error.ipp. The function has a static boost::asio::error::detail::netdb_category object that it returns a const reference to. When I use nm to inspect the main executable the symbol appears in the data segment and the type for boost::asio::error::detail::netdb_category()::instance is "u", which indicates that the compiler has marked this as a globally-unique symbol. The problem occurs when the loader loads the third-party shared library. Because the symbol boost::asio::error::detail::netdb_category()::instance has been marked as unique in the shared library as well (verified by running readelf on the .so), the loader decides that it will simply use the one from the executable. Because the shared library's version of the object is larger than the executable's version, when it is constructed it overwrites the 16 bytes beyond the end of the executable's object, trashing the contents of the data segment that were there previously. I tried using the -fno-gnu-unique flag when compiling our executable, but that doesn't fix the problem - it marks the symbol as weak in the main executable, but the shared library, because I cannot re-compile, still has the symbol marked as unique. I tried using dlopen with RTLD_LOCAL and that fixes the problem of overwriting the main executable's memory, however the corresponding symbols in the shared library have pointers back into the main executable's data segment (where the corresponding netdb_category static lives), which means that when if the shared library accesses these objects it will be following invalid pointers as it will overlay a larger v1.66 object onto a smaller v1.63 object. Has anyone encountered a problem like this? And, if so, did you find a good solution? Much thanks, Jamie

4 4

[locale] gettext functions: std::locale default argument not working
by Jeanette C. 29 Apr '19

29 Apr '19

Hey hey, it appears that the std::locale const &loc=std::locale() argument of the gettext functions for direct message translation doesn't properly pick up the program's global locale. Assume that messages have been extracted and translated. Consider the code snippet below: ... boost::locale::generator gen; std::locale loc = gen("de_DE"); std::locale::global(loc); // std::locale loc2; // will also work as argument to gettext string s = boost::locale::gettext("Hello world"); // output "Hello world" string t = boost::locale::gettext("Hello world",loc); // output "Hallo Welt" ... I am on boost 1.69.0-2, Arch Linux package, gcc 8.2.1, libstdc++ 6.0.25 (taken from the dynamic library filename), this is distributed with the GCC package. I'd appreciate any hint to solve this, since it would mean a lot of code editing otherwise. Best wishes and thanks, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * SoundCloud: https://soundcloud.com/jeanette_c * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * GitHub: https://github.com/jeanette-c * Twitter: https://twitter.com/jeanette_c_s Cinderella's got to go <3 (Britney Spears)

1 0

[locale] Using generator with std::locale always yields name *
by Jeanette C. 29 Apr '19

29 Apr '19

Hey hey, When I use the boost::locale::generator to initialise an std::locale the std::locale.name() always yields "*". Examples: ... boost::locale::generator gen; std::locale loc = gen("en_US"); std::cout << loc.name(); ... output: * Whereas using the std::locale constructor with const char * yields the proper name: ... std::locale loc("en_US"); std::cout << loc.name(); ... Output: en_US I am running on Arch Linux, with Boost version 1.69.0-2 (the latest version in the official Arch package repositoy). Is there a caveat I overlooked or is there another way around this behaviour? One word of praise: the Boost locale library gave me the first pleasant experience of using localisation. I love the interface and think it very understandable even for a programmer of only mediocre level like myself. So: thank you! Best wishes, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * SoundCloud: https://soundcloud.com/jeanette_c * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * GitHub: https://github.com/jeanette-c * Twitter: https://twitter.com/jeanette_c_s I thought love was just a tingling of the skin <3 (Britney Spears)

2 2

Windows batch file to build for multiple compiler versions
by Kenneth Porter 25 Apr '19

25 Apr '19

Here's the batch file I use to build the binary libraries for each new version of Boost for all the compilers and architectures my own library supports. Suggestions for improvements are welcome. Just define the boost_root environment variable and run it. https://gist.github.com/SpareSimian/2a0f1fd1718d81ce2441218ded776778

2 1

[MP11] Loosing const-qualification on type result with GCC 4.8 only
by Mateusz Loskot 25 Apr '19

25 Apr '19

Hi, I prepared a lenghty MWE which reproduces my problem with type manipulation using MP11 that for some reason looses const-qualification on a ::type result Here it is at https://godbolt.org/z/eCsakP and copied below. I hope the XXXXXX comments make sense and important static assertions in the main() at the bottom explain what is the expected result. ``` #include <boost/mp11.hpp> #include <cstdint> #include <type_traits> namespace mp11 = boost::mp11; template <typename BitField, int FirstBit, int NumBits, bool IsMutable> struct bit_range_reference { /* long definition, irrelevant */ }; template <typename BitField, typename FirstBit, typename NumBits> struct bit_range_reference_type { using type = bit_range_reference < BitField, FirstBit::value, NumBits::value, true > const; // XXXXXX Why this const gets lost with GCC 4.8 XXXXXX }; template <typename BitField, typename RangeBitSizes> class bit_range_reference_list { template <typename FirstBit, typename NumBits> using reference_type = typename bit_range_reference_type < BitField, FirstBit, NumBits >::type; // XXXXXX Should carry the const, shouldn't? GCC >4.8 do. // If RangeBitSizes is mp11::mp_list_c<int,7,7,2> // then first_bit_list will be mp11::mp_list_c<int,0,7,14,16> using first_bit_list = mp11::mp_fold_q < RangeBitSizes, mp11::mp_list<std::integral_constant<int, 0>>, mp11::mp_bind < mp11::mp_push_back, mp11::_1, mp11::mp_bind < mp11::mp_plus, mp11::mp_bind<mp11::mp_back, mp11::_1>, mp11::_2 > > >; static_assert(mp11::mp_at_c<first_bit_list, 0>::value == 0, "first bit must be 0"); public: using type = mp11::mp_transform < reference_type, mp11::mp_pop_back<first_bit_list>, RangeBitSizes >; }; using reference3_list = typename bit_range_reference_list < std::uint8_t, mp11::mp_list_c<int, 3> >::type; int main() { using r1_t = mp11::mp_at_c<reference3_list, 0>; using r2_t = bit_range_reference<std::uint8_t, 0, 3, true>; using r2c_t= bit_range_reference<std::uint8_t, 0, 3, true> const; //#if defined(__GNUC__) && (__GNUC__ == 4) // GCC 4.8 compiles, later versions of GCC fail to compile static_assert(std::is_same<r1_t, r2_t>::value, "GCC says r1_t is const-qualified"); //#else // GCC 4.9, 5, 6, 7, 8 versions compile, GCC 4.8 fail to compile static_assert(std::is_same<r1_t, r2c_t>::value, "GCC says r1_t is NOT const-qualified"); //#endif } ``` To summary, I expect this to yield true: std::is_same < mp11::mp_at_c<reference3_list, 0> bit_range_reference<std::uint8_t, 0, 3, true> const > I got this confirmed by all GCC versions but GCC 4.8. (clang and MSVC also seem to agree with the GCC >= 4.9) Is mp11::mp_transform loosing const-qualification or have I made a mistake somewhere? I'm using Boost.MP11 from Boost 1.70 and from current develop branch Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

Building Boost 1.70 with VS2019?
by Osman Zakir 19 Apr '19

19 Apr '19

Hi, everyone. How can I have Boost.Build use VS2019 when building Boost? I have a side-by-side installation of VS2019 on my computer, along with VS2017 also still being there. If this hasn't been tested yet, I'll wait until it has.

3 4

boost::xpressive use of before(...)
by Simon Giddings 18 Apr '19

18 Apr '19

Good morning, In our project I have the enviable task of transforming a large number of perl regex into boost::xpressive static code in c++. To ensure that the code I write, I have put together a simple test app where I create the sregex object and can then test that the result is that which is exected. I am stuck with the use of before(...) Here is my test - which fails std::string strInput = "&9-A02FEfoo"; sregex re; re = bos >> as_xpr("&9-A02FE") >> before("foo"); if(regex_match(strInput, sm, re)) { strResult = "matched : " + sm[0].str(); } According to the documentation (v1.67) this should work. What am I doing wrong here ? Best regards Simon

2 1

Need help resolving Boost error with Log Library: Candidate function not viable, expects an l-value for 1st argument
by Austin Tapp 15 Apr '19

15 Apr '19

Hello, I am trying to resolve this error: "5. Candidate function [with LoggerT = boost::log::v2s_mt_posix::sources::severity_logger_mt<boost::log::v2s_mt_posix::trivial::severity_level>] not viable: expects an l-value for 1st argument". This error results in the inability to use the function "make_record_pump", in my .cxx file, because "make_record_pump" is not recognized as a function within "record_ostream.hpp" due to the previous error. I am attempting to compile this project on Xcode 10.2, after building the project with the newest version of CMake. I have built boost (version 1.69.0) and installed the dynamic libraries with homebrew. Thank you, Austin Tapp

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

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[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

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[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

[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

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Re: [Boost-users] [boost] [release] Boost 1.70.0 Release Candidate 1 available
by Vinnie Falco 09 Apr '19

09 Apr '19

On Mon, Apr 8, 2019 at 3:51 PM Stefan Seefeld <stefan(a)seefeld.name> wrote: > At this point in time, I'd argue...fixes, to make sure... > But soft, what commit through yonder git log states? It is a bug, and 5e88637752ea0ecb49824904be3098656740298c is the fix! ... To merge, or not to merge? That is the question. Regards

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[release] Boost 1.70.0 Release Candidate 1 available
by Marshall Clow 08 Apr '19

08 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

8 15

Newbie error trying to construct an offset_ptr in a managed shared memory segment.
by Bill Baker 03 Apr '19

03 Apr '19

1 0

cannot compile boost pmr small_vector snippet
by Pedro Pinto pedro.pinto＠bluetradesys.com 02 Apr '19

02 Apr '19

Hi there, I am trying to use the pmr version of the boost small_vector container. I expected the following to work: #include <boost/container/pmr/polymorphic_allocator.hpp>#include <boost/container/pmr/small_vector.hpp> boost::container::pmr::polymorphic_allocator<int> alloc; boost::container::pmr::small_vector<int,4> vec(alloc); But this does not compile with boost 65, gcc 7.3/clang 6.0. The compile error seems to suggest I should be using small_vector_allocator which is an internal class. The exact clang error is below. Am I missing something here? Thanks /usr/include/boost/container/small_vector.hpp:514:41: note: candidate constructor not viable: no known conversion from 'boost::container::pmr::polymorphic_allocator<int>' to 'const boost::container::small_vector<int, 4, boost::container::pmr::polymorphic_allocator<int> >::allocator_type' (aka 'const small_vector_allocator<boost::container::pmr::polymorphic_allocator<int> >') for 1st argument BOOST_CONTAINER_FORCEINLINE explicit small_vector(const allocator_type &a)

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[variant2] Review of Variant2 started today : April 1 - April 10
by Michael Caisse 02 Apr '19

02 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> The master branch will be stable for the review: <https://github.com/pdimov/variant2/tree/master> Find the documentation here (also stable during the review): <https://pdimov.github.io/variant2/doc/html/variant2.html> Note: The repository contains an expected implementation also; however, that is not being considered in this review. Please provide in your review information you think is valuable to understand your choice to ACCEPT or REJECT including Variant2 as a Boost library. Please be explicit about your decision (ACCEPT or REJECT). Some other questions you might want to consider answering: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With which compiler(s)? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? More information about the Boost Formal Review Process can be found here: <http://www.boost.org/community/reviews.html> Thank you for your effort in the Boost community. Happy coding - michael -- Michael Caisse Ciere Consulting ciere.com

1 0

[boost][stacktrace] stacktrace keep eating memory
by Hao Jiang 29 Mar '19

29 Mar '19

I am using stacktrace on Windows. I found stacktrace keep eating my memory. A simple test program: void foo() { auto st = boost::stacktrace::stacktrace{}; auto line = st.begin()->source_line(); std::cout << line << std::endl; } void main() { for (int i = 0; i < 0xFFFF; i++) { foo(); } } Based on MSVC memory profiling tool, memory usage keep growth: [cid:image001.png@01D4DF46.BA4E1090] And frame allocator is taking heap: [cid:image004.png@01D4DF47.6F38C310] Anyone knows why it happens? Br, Hao. Platform: Windows 7. Compiler: MSVC 2017 Boost version: 1.67 Compile and link: release, static-link, static runtime.

2 1

[dll] Notifying a plugins host that a plugin should be unloaded
by Sean Farrow 29 Mar '19

29 Mar '19

Hi all, I have an application that uses boost.dll to provide plugin functionality. I have a base class defined that all plugins derive from. I'm looking for a way to notify the host application that a particular plugin should be unloaded. This is determined by the plugin itself. Is signals/slots appropriate here or is there a better option? Has anyone else done anything like this? Any help appreciated. Kind regards Sean.

2 1

[range] Conflict with string algorithms
by Bill Buklis 29 Mar '19

29 Mar '19

I noticed there is a conflict between boost range and the string algorithm header files. There may be others, but the specific one I was dealing with was boost::find. For example, the following code results in an ambiguous warning. This is because boost::find is defined both in algorithm/string/find.hpp and range/algorithm/find.hpp. #include <vector> #include <boost/range/algorithm.hpp> #include <boost/algorithm/string.hpp> int main() { std::vector<int> vec; boost::find(vec, 3); } Is this intentional or is it is an oversight or am I just doing something wrong? -- Bill

2 1

[review][variant2] Variant2 Review Starts April 1
by Michael Caisse 24 Mar '19

24 Mar '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 -- Michael Caisse Ciere Consulting ciere.com

1 0

How to keep a pointer on a shared data in a boost shared memory segment
by jucin loic 24 Mar '19

24 Mar '19

Hi everyone ! How to keep a pointer on a shared data in a boost shared memory segment ? I have a function which returns shm.construct<SharedData>(_nameSeg.c_str())(innerDataAllocator); But outside of the function, the object pointed by SharedData is inaccessible My general problem is that I want to have way to get, and set data in shared memory, but without, each time, having to : -get shm -find object in shm based on its name -construct allocators. So I would like to store 1) allocators and 2)a pointer to the shared object How could I do this ? I made a SO question about my problem, can you have a look ? It should be clearer :) https://stackoverflow.com/questions/55195149/how-to-keep-a-pointer-on-a-sha…

4 5

Future of boost.compute
by Heriberto Delgado 23 Mar '19

23 Mar '19

My apologies if this has been asked before. To be honest, I'm not good doing stuff with mailing lists. However, this is something about which I would really like to know your opinion. With Apple recently deprecating OpenCL / GL technologies in their software, and the newer APIs on the market - Vulkan, Metal - and current native APIs - DX Compute, also Metal Compute - , it sure looks like boost.compute, which is essentially a wrapper around OpenCL, is on its way to become a legacy API. That is, unless the API gets modified to allow multiple APIs and platforms. So, what do you think is going to happen? Is boost.compute eventually going to "disappear" (similar to how boost pointer classes were replaced by std:: pointer classes), or is there some kind of effort to move it beyond OpenCL and into newer APIs? - Heriberto Delgado.

1 0

Re: [Boost-users] Zero-malloc memory pool for Boost Intrusive smart pointers
by Gavin Lambert 23 Mar '19

23 Mar '19

At 09:25 23/03/2019, Francesco wrote: >Yes I know about std::make_shared<> and indeed I >was using that solution before implementing the >memory pool based on intrusive pointers. >The problem is that in my workload I have >several threads that need to get a smart pointer >to a fairly-big object every time they process >input data and they will release it later. Which brings up another point; your current implementation is not thread-safe. Which is fine, but you should probably mention that explicitly in your readme. A very common worker pattern is to have all allocations on one thread and all deallocations on another thread, and that wouldn't work as-is. >Now allocating with std::make_shared<>Â a new >object on every input data was causing my >threads to do lots of mallocs/sec and that >became the performace limiting factor. >The use of a memory pool instead allows me to do >a very large memory allocation from time to time >(in blocks of e.g. 1024 items) and still have >each single item of the memory pool independently refcounted. Yes, I realise that. It still could be possible to have individual node allocations strung up into a free list rather than requiring a larger contiguous allocation. But you're correct that arena allocation and intrusive_ptr is probably more efficient in the end. >My first implementation of the memory pool >indeed was using C++11 perfect forwarding to >call the ctor/dtor of type T when the item was >pulled out the pool or was returning to it. >I later removed such feature because I realized >that calling the ctor of the items to recycle >produced issues with classes having multiple inheritance IIRC. >I don't think it's safe and sane to call the >ctor of the same instance multiple times...Â Calls must be paired -- you allocate aligned uninitialised storage (aligned_storage), then placement-new to call the constructor on that storage, then eventually call the destructor, and then later you can placement-new again. You must never call the constructor twice in a row or the destructor twice in a row (unless it's trivial), but alternating is fine. Again, this is how things like optional and variant work internally -- and since they do that part for you, it can be useful to re-use it rather than re-implementing it.

2 1

Zero-malloc memory pool for Boost Intrusive smart pointers
by Francesco 22 Mar '19

22 Mar '19

Hi all, I have developed for my needs a C++11 memory pool that can provides C++ object instances in the form of boost::intrusive_ptr<> that automatically return to the pool once their refcount goes to zero. I found the need for such memory pool to have a zero-malloc memory pool algorithm for some performance-oriented applications that were relying on std::shared_ptr<>. Here's the link in case anybody is interested: https://github.com/f18m/boost-intrusive-pool with some (initial) benchmark as well. I thought that this may be useful to anybody else already using Boost intrusive pointers as well... Any comment is welcome! Francesco Montorsi

2 2

compile error, boost_1_70_0_b1, C++17, MSVC 1916, "/Zc:noexceptTypes-" compiler flag
by Thomas Wollenzin 20 Mar '19

20 Mar '19

Hello, We came across a compiler error with Boost version 1.70.0 b1 when compiling via MSVC 1916, C++17 standard and the "/Zc:noexceptTypes-" compiler flag set. The resulting error is of type: boost\type_traits\detail\is_member_function_pointer_cxx_11.hpp(359): error C2953: 'boost::is_member_function_pointer<Ret(__cdecl C::* )(Args...)>': class template has already been defined boost\type_traits\detail\is_member_function_pointer_cxx_11.hpp(48): note: see declaration of 'boost::is_member_function_pointer<Ret(__cdecl C::* )(Args...)>' A corresponding issue was created here: https://github.com/boostorg/type_traits/issues/118 We're wondering of the chances of getting this fixed with the final 1.70 release and if possible would like to get priority on a fix. Thanks for your time! Kind regards, Thomas Wollenzin ___________ Crytek GmbH / Hugo-Junkers-Strasse 3, 60386 Frankfurt am Main / HR B 77322 Amtsgericht Frankfurt am Main / Geschäftsführer/Managing Directors: Avni Yerli, Faruk Yerli, Ahmet Sahin / VAT-ID DE20432461 / www.crytek.com

1 0

Update to problem of http::request call failing
by Osman Zakir 20 Mar '19

20 Mar '19

Hi. I still have the same exception, but I did notice something I was doing wrong: the API endpoint and the key for the request to the currency API were wrong. I fixed them, but the exception is still there. I sent an email to the OpenSSL users mailing list to ask them if I did anything wrong in the root certificate stuff. Entire source code for app is on GitHub here: https://github.com/DragonOsman/currency_converter .

1 0