April 2015 - Boost-users - lists.preview.boost.org

1.58.0 rc3 is now available
by Marshall Clow 22 Apr '15

22 Apr '15

Release candidate files for 1.58.0 are available at: http://boost.cowic.de/rc/ * Since rc1, the changes that were causing the serialization libraries to fail to build on MSVC have been reverted. * Since rc2, the documentation for bind, and mem_fun. No code changes. 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. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (boost_1_58_0_rc3.7z) = f7255aeb692c1c38fe761c32fb0d3ecd MD5 (boost_1_58_0_rc3.tar.bz2) = b8839650e61e9c1c0a89f371dd475546 MD5 (boost_1_58_0_rc3.tar.gz) = 5a5d5614d9a07672e1ab2a250b5defc5 MD5 (boost_1_58_0_rc3.zip) = b0605a9323f1e960f7434dbbd95a7a5c Thanks! -- The release managers P.S. Release notes are here: http://www.boost.org/users/history/version_1_58_0.html

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Re: [Boost-users] [IPC Named Mutex]
by Lorenzo Trivelli 21 Apr '15

21 Apr '15

Hi Tom, I tried your solution and it worked, and I'm stil wondering about the rationale behind the bootup time usage ;-) I also submitted a bug ticket, #11194, but track took a very long time to create it and add the test case, and in the end I found that: 1) a bug with ticket !11195 was also created 2) the test case was attached four times :-( can anyone please clean it up as is is a quite ugly ? ;-) regards Lorenzo

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Re: [Boost-users] [Serialization / 1.58] wrong number of entries in std::vector<boost::tuple<double, double, double> >
by Rüdiger Berlich 21 Apr '15

21 Apr '15

Hi Robert, I have submitted trac item 11214 and attached the test case. The trac web interface somehow froze for me upon submission (Safari / MacOS), and I apparently have pressed the submit button more than once, trying to submit the track item. So it appears as if more than one ticket has been created (11215 - 11218), which I do not seem to be able to delete. Please ignore these -- apologies. Best Regards, Beet > > ouch! - make a trac item for this! > > Robert Ramey > > > > -- > View this message in context: http://boost.2283326.n4.nabble.com/Serialization-1-58-wrong-number-of-entri… > Sent from the Boost - Users mailing list archive at Nabble.com. > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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Web doc 1.58 Categorized error
by Larry 20 Apr '15

20 Apr '15

I tried to look at the 1.58 doc on the website and clicking on Categorized gave me under the headings By Category Unknown category: Data structures Apparently missing something. “All”, “Standard Proposals” etc seem to work. Larry

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[Serialization / 1.58] wrong number of entries in std::vector<boost::tuple<double, double, double> >
by Rüdiger Berlich 20 Apr '15

20 Apr '15

Hi, I’ve just installed Boost 1.58 and ran into the following problem: I have a class with a std::vector<boost::tuple<double, double, double> >, that is supposed to always have at least one entry, but may have more. Hence, in the default constructor, I initialize the std::vector with one entry. The class is also serializable. Up until Boost 1.57, a de-serialized object always had the correct number of entries in the vector. As of 1.58, I am getting one entry too much, which probably means that Boost.Serialization simply attaches entries to the vector of a default-constructed class, but doesn’t clear it first. This happens in C++11-Mode, both on Ubuntu 14.10 (gcc 4.9.1) as well as on MacOS X Yosemite . It DOES NOT happen with a std::vector<double> . Below is a full test case that replicates the problem in a simplified environment. For Boost 1.57 the program returns: t_vec.size() = 1 t_vec2.size() = 1 For Boost 1.58 the answer is t_vec.size() = 1 t_vec2.size() = 2 Best Regards, Beet /******************************************************/ #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/serialization/nvp.hpp> #include <boost/serialization/vector.hpp> #include <boost/tuple/tuple.hpp> #include <iostream> #include <vector> #include <sstream> namespace boost { namespace serialization { template<typename archive, typename T0, typename T1, typename T2> void serialize(archive & ar, boost::tuple<T0, T1, T2> & tpl, unsigned int) { using namespace boost; using boost::serialization::make_nvp; ar & make_nvp("tpl_0", boost::get<0>(tpl)) & make_nvp("tpl_1", boost::get<1>(tpl)) & make_nvp("tpl_2", boost::get<2>(tpl)); } } /* namespace serialization */ } /* namespace boost */ int main() { std::vector<boost::tuple<double, double, double> > t_vec, t_vec2(1); std::ostringstream oss; t_vec.push_back(boost::tuple<double, double, double>(1.,2.,3.)); std::cout << "t_vec.size() = " << t_vec.size() << std::endl; // save data to archive { boost::archive::xml_oarchive oa(oss); // write class instance to archive oa & BOOST_SERIALIZATION_NVP(t_vec); // archive and stream closed when destructors are called // Data is now in oss } // load data from archive { std::istringstream iss(oss.str()); boost::archive::xml_iarchive ia(iss); // read class state from archive ia & BOOST_SERIALIZATION_NVP(t_vec2); // archive and stream closed when destructors are called } std::cout << "t_vec2.size() = " << t_vec2.size() << std::endl; }

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Compile errors in pointer_traits.hpp after upgrade to 1_58_0
by James Walker 20 Apr '15

20 Apr '15

After switching from Boost 1_57_0 to 1_58_0, I get various compile errors in pointer_traits.hpp, where it uses the macro BOOST_INTRUSIVE_HAS_STATIC_MEMBER_FUNC_SIGNATURE: warning: declaration does not declare anything error: use of undeclared identifier 'check' error: 'U' does not refer to a value This is with Xcode 4.6.3 and the Apple LLVM 4.2 compiler.

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Boost Spirit Karma - convert character to hex representation
by Ernest Zaslavsky 20 Apr '15

20 Apr '15

There is karma::hex formatter and I need somehow to add zero padding to get “0a” instead of just “a”. in addition it would be lovely to have some king of control over hex letter case. It sounds like a policies for real or Boolean formatters but I didn’t find one for hex. Is it possible to achieve the above without policy? [Read More]<http://feeds.feedburner.com/~r/sizmek-blog/~6/1> [http://www.sizmek.com/Sizmek.png]<http://www.sizmek.com/>

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Re: [Boost-users] Boost 1.58.0 has been released
by Florent Guiliani 20 Apr '15

20 Apr '15

On 4/18/15 6:00 PM, boost-users-request(a)lists.boost.org wrote: > On Fri, Apr 17, 2015 at 8:59 PM, Tom Kent<lists(a)teeks99.com> wrote: >> > >> >On Fri, Apr 17, 2015 at 3:58 PM, Marshall Clow<mclow.lists(a)gmail.com> >> >wrote: >>> >> >>> >>Release 1.58.0 of the Boost C++ Libraries is now available. > You sure about that? > Did you forget to push the release tag on Github? https://github.com/boostorg/boost/releases The release tag boost-1.58.0 is missing on Github. -- Florent

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Compile error with boost::factory after upgrade to 1.58.0
by Bitar Fadi 18 Apr '15

18 Apr '15

Hi, I installed Boost 1.58.0 today, having been using 1.57.0 previously, and noticed that a part of my code that uses boost::factory doesn't compile anymore. Here's briefly what I'm doing, followed by the error message I'm getting: typedef boost::function<Apollo::ReportGenerator*(Apollo::ApolloBaseModel*)> reportFactory; struct reportListing { std::string displayName; reportFactory factory; reportListing(std::string name, reportFactory f) : displayName(name), factory(f) { } }; std::vector<reportListing> reportFactories; reportFactories.push_back(reportListing("Scenario Analyzer", boost::factory<Apollo::ScenarioAnalyzer*>())); // Apollo::ReportGenerator being the base class from which Apollo::ScenarioAnalyzer is derived ... The constructor for ScenarioAnalyzer is: ScenarioAnalyzer(Apollo::ApolloBaseModel* model) This fails to compile with the following error (on Windows 7 using Visual C++ 12): error C2664: 'Apollo::ScenarioAnalyzer *boost::factory<Pointer,void,factory_alloc_for_pointee_and_deleter>::operator ()(void) const' : cannot convert argument 1 from 'Apollo::ApolloBaseModel *' to 'Apollo::ApolloBaseModel *&' I'm just wondering if that is caused by an intentional change or not, because according to the change log to boost::factory no significant changes with implications to backward compatibility have been made. Also, I'm not sure I know how to get rid of this error. Thanks for the help! /Fadi ________________________________ Fadi Bitar Modeling and simulation specialist Energy Markets Telephone direct +46 (0)8 695 64 05 Mobile +46 725 40 64 05 fadi.bitar(a)sweco.se<mailto:fadi.bitar@sweco.se> Sweco Energuide AB Gjörwellsgatan 22 P.O. Box 34044 SE-100 26 Stockholm Telephone +46 8 695 60 00 www.sweco.se<http://www.sweco.se/> [cid:image001.jpg@01CECF3E.855DC4C0] Please consider the environment before printing this e-mail.

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Boost 1.58.0 has been released
by Marshall Clow 18 Apr '15

18 Apr '15

Release 1.58.0 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 two new libraries and numerous enhancements and bug fixes for existing libraries. New Libraries * Endian: Types and conversion functions for correct byte ordering and more regardless of processor endianness. * Sort: Includes spreadsort, a general-case hybrid radix sort that is faster than O(n*log(n)) For details, including download links, see http://www.boost.org/users/news/version_1.58.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.58.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

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How to suppress warnings from boost headers
by avib369 . 17 Apr '15

17 Apr '15

Is there any way using boost to suppress warning messages issued from the boost headers ? Is there a way to replace -I with -isystem ? Ta, Avi

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multiprecision -- eigen matrices using dynamically allocated variable-precision mpfr_float
by Daniel Brake 17 Apr '15

17 Apr '15

I'd like to use the variable-precision mpfr_float type offered by the Boost.Multiprecision library, with the templated Eigen linear algebra library. I observe that if I make an identity matrix created with dynamically-allocated variable-precision mpfr_floats, and multiply it against itself, every other row is populated with nan's. Here is some code: int main(){ int size = 9; typedef boost::multiprecision::mpfr_float_backend<0, boost::multiprecision::allocate_dynamic> mybackend; typedef boost::multiprecision::number<mybackend, boost::multiprecision::et_on> mynumtype; typedef Eigen::Matrix<mynumtype, Eigen::Dynamic, Eigen::Dynamic> mp_matrix; mp_matrix A = mp_matrix::Identity(size, size); mp_matrix B = A*A; std::cout << B << std::endl; return 0; } output: 1 0 0 0 0 0 0 0 0 nan nan nan nan nan nan nan nan nan 0 0 1 0 0 0 0 0 0 nan nan nan nan nan nan nan nan nan 0 0 0 0 1 0 0 0 0 nan nan nan nan nan nan nan nan nan 0 0 0 0 0 0 1 0 0 nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan I have been able to pin it down to the allocate_dynamic switch; if I select allocate_stack, the product computes correctly; allocate_dynamic reliably generates nans. Fixed-precision numbers work just fine, and expression templates on/off make no difference. I'd like to use the dynamic allocation, as I expect to use thousands of digits at times. I am using clang++, with c++11, on OSX, Boost 1.57.0, Eigen 3.2.4. Same behaviour in 1.56 / 3.2.3. It seems like maybe an offset issue, but I just can't get there by myself. I've also played with defining the NumTraits in Eigen various ways, but nothing affects the nan behaviour. Does anyone have any ideas? Daniel Brake Postdoctoral Research Scholar University of Notre Dame

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[boost][thread] thread_local vs boost::thread_specific vs ::pthread_key_t
by chilabot＠gmail.com 16 Apr '15

16 Apr '15

I have a program that dlopens some libraries (all C++), that use TLS for a variable (which passed to all libraries). With the keyword 'thread_local' and with 'boost::thread_specific', the storage of the variable is different for every thread AND for every shared library. With 'pthread_key_t' it's only different for every thread, it behaves as expected. I guess 'boost::thread_specific' uses 'thread_local' and that's why it behaves like it. Why does 'thread_local' behave like this? $ clang --version Ubuntu clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on LLVM 3.5.0) Target: x86_64-pc-linux-gnu Thread model: posix $ uname -a Linux robert-y510p 3.13.0-49-generic #81-Ubuntu SMP Tue Mar 24 19:29:48 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux ref http://stackoverflow.com/questions/29656089/ thread-local-vs-boostthread-specific-vs-pthread-key-t

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[IPC Named Mutex]
by Lorenzo Trivelli 16 Apr '15

16 Apr '15

Hi to everyone, I'm experiencing a strange behaviour of named mutex on a windows 2008 machine. symptoms: when the system event log is empty, creation of named mutex fails with a boost::interprocess::interprocess:exception with msg boost::interprocess_exception::library_error. Now some data: 1) Boost 1.57.0 + stlport 5.2 2) VS 2005 3) Target Environment: Win 2008/32 3) after a night of code digging I managed to crete a small sample which raises the exception: #include <boost/shared_ptr.hpp> #include <boost/interprocess/sync/named_mutex.hpp> #include <boost/interprocess/sync/scoped_lock.hpp> #include <iostream> typedef boost::shared_ptr<boost::interprocess::named_mutex> safe_ipc_mx; static safe_ipc_mx __mx; int main(void) { system("pause"); try { __mx = safe_ipc_mx(new boost::interprocess::named_mutex(boost::interprocess::open_or_create_t(),"JAEGER")); std::cout << std::endl << "Mutex created !" << std::endl; } catch(boost::interprocess::interprocess_exception const& e) { std::cout << std::endl << "Mutex creation error " << e.what() << " /" << e.get_error_code() << " /" << e.get_native_error(); } system("pause"); return 0; } as far as I digged, it seems that the trouble is in the winapi::get_last_bootup_time(stamp) call in shared_dir_helpers.hpp, but up to now I had not been able to reproduce it on a machine with all the debugging tools installed does anyone have a clue on what I am doing wrong ? thanks in advance Lorenzo

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Re: [Boost-users] Project linking problem with boost
by Max 16 Apr '15

16 Apr '15

----- Original Message ----- From: <Mark.Bartosik(a)thomsonreuters.com> To: <boost-users(a)lists.boost.org> Subject: Re: [Boost-users] Project linking problem with boost Date: 2015-04-15 22:59 Try one of the /VERBOSE options on the linker’s command line will get you this information, I cannot remember which is the most painless one though. From the command line: /VERBOSE[:{CLR|ICF|INCR|LIB|REF|SAFESEH|UNUSEDLIBS}] /VERBOSE:LIB You can find this under Properties, Linker, General, Show Progress You can also set directly Properties, Linker, Command Line As I recall just /VERBOSE:LIB should generate a lot of output about which library is pulled in (and hopefully by which other library). Just the /VERBOSE output generate a huge amount of output (minimize the window and open with text editor later or it will be a long wait). - Mark - ------------------------------------------------------ Dear Mark, Thank you very much for your information - I didn't know this technique before. The problem is, though the problem seemed to be related to the linking process, the message as in my previous email was emitted by VS2008 before the linking process begins. So for the time being, I cannot benefit from adding extra switches to the link command. Best regards,Max --------------------------------------------------- From: Boost-users [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Max Sent: Wednesday, April 15, 2015 5:49 AM To: boost-users Subject: [Boost-users] Project linking problem with boost Sent: Wednesday, April 15, 2015 5:49 AM To: boost-users Subject: [Boost-users] Project linking problem with boost Hello, The problem here relates to boost, but I'm aware it may of more general nature rather than boost specific. I had a weird problem with my project. It has a bunch of dependencies including many of the boost libraries. My platform is: Win7SP1 + VS2008SP1 + boost1.39.0. I have properly set the VC++ directories for both include and lib files pointing to the boost folder (1.39.0) and of course those for other dependencies. But I got the following message when I built the project: 1>Linking to GSL lib 1>Linking to lib file: CGAL-vc90-mt.lib 1>Linking to lib file: libboost_date_time-vc80-mt-1_34.lib 1>Linking to lib file: libboost_regex-vc80-mt-1_34.lib I don't know why VS was attempting to link to libs of boost 1.34.0 built with VC80 (I'm using VC 90 - VS2008) Could anybody please give me some hints about this problem or where the message like "Linking to lib file: ..." came from? Thanks. Best regards, Max _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: [Boost-users] Project linking problem with boost
by Max 16 Apr '15

16 Apr '15

----- Original Message ----- From: Lorenzo Trivelli <trivelli.lorenzo(a)konvergence.it> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Project linking problem with boost Date: 2015-04-15 22:32 Sorry, it may sound a dumb question but are you sure that there are no 1.34 includes before the 1.39 or that there is no hardcoded 1.34 include in your code ? regards Lorenzo Dear Lorenzo, Thank you for your hints and sorry for not giving more details.I don't have the 1.34.0 version of boost on my machine and I have no hardcoded dependencies on it in my code. Best regards,Max

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[Build Boost] Failed gcc.archive
by Jan Krämer 16 Apr '15

16 Apr '15

Hi all, I am trying to build boost_1_57 on Windows7 with MinGW64 (tried gcc 4.9 and 4.9.2). Compiling works fine but gcc.archive fails with: gcc.archive bin.v2\libs\atomic\build\gcc\debug\address-model-64\link-static\threading-multi\libboost_atomic-gcc-mt-d-1_57.a '"C:\mingw-w64\mingw64\bin"' is not recognized as an internal or external command, operable program or batch file. '"C:\mingw-w64\mingw64\bin"' is not recognized as an internal or external command, operable program or batch file. It does that on every gcc.archive operation. I read that this can be caused when using a path with spaces inside, which is not the case here. I did not found any other information and I am stuck right now. Full console output can be found at: http://pastebin.com/bWP0WHAA used commands were: > bootstrap.bat mingw > b2 --prefix=C:/Boost toolset=gcc address-model=64 install --debug-configuration >> boost.log Thanks in advance, any help would be appreciated. Cheers, Jan

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Re: [Boost-users] boost vs std atomic sequential consistency semantics
by Isaac To 16 Apr '15

16 Apr '15

On Wed, Apr 15, 2015 at 4:34 PM, Olivier Tristan <o.tristan(a)uvi.net> wrote: Have you tried Boost LockFree ? > http://www.boost.org/doc/libs/1_55_0/doc/html/lockfree.html > which handle multiple producer/Multiple-consumer queue > I know about the lockfree library, I've read the book underlying it (the Art of Multiprocessor Programming), and think I've understood at least 80% of it. My problem is not multiple producer multiple consumer queue, so it doesn't work for me. In particular, although there are multiple log producers, there is no consumer. They log into a ring buffer, and normally nobody would care and the log entries get overwritten by new entries (I want to avoid having to wait when logging). When the reader wants to read, it simply dumps everything in the ring buffer, and won't change the status of the buffer (i.e., it doesn't "consume"). And I don't care if the reader found a few entries are busy being overwritten, it just has to know about that so as to avoid using the data (which leads to wrong output and could lead to crash). The problem is in fact a lot easier than any of the queues / stacks that is implemented by lockfree. I've also inspected the assembly generated by g++ over my code in x86-64, and I think it is okay (i.e., no reordering with non-atomic statement is done by the compiler -- together with the strong consistency guarantee under x86-64 the code should be okay I think). Of course, "okay for one version of a brand of compiler and library under one platform" does not mean my program is correct: a new version of the compiler / library could break it, which is my main worry. But I've got something more fundamental to ask: what the memory model really means, and what to do once we (inevitably) move away from Boost and join the C++1x/y/z family. It seems to me that the C++ standard provides something quite a bit weaker than what Boost promises, and I don't know how to get the Boost promise from the C++ standard. That's the other reason why I ask. > Le 15/04/2015 08:42, Isaac To a ?crit : > > > I'd like to write a C++ object where there are many logger threads > > logging to a large global (non-atomic) ring buffer, with an occasional > > reader thread which wants to read as much data in the buffer as > > possible. I ended up having a global atomic counter where loggers get > > locations to write to, and each logger increments the counter > > atomically before writing. The reader tries to read the buffer and > > per-logger local (atomic) variable to know whether particular buffer > > entries are busy being written by some logger, so as to avoid using them. > Regards, Isaac

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Re: [Boost-users] Possible to use with JNI?
by Lorenzo Trivelli 15 Apr '15

15 Apr '15

At 06:30 13/04/2015, you wrote: >Hi, I really need to use Java with this library. Is it possible to use JNI on this library or do I need to convert this library to Java? I find the latter task is going to be really difficult so I hope that I can use JNI. > >Thank you for your help. Hi, AFAIK it is not easy to do that due to C++ name mangling and the absence of any ABI in C++ itself like C A possible but limited workaround should be to create a DLL with a C interface which uses the boost objects you need. Next, you can call it through JNI, but obviously you can pass only basic data types regardds Lorenzo

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[asio][bind] Access violation with placeholders used by static objects
by Olivier Sauvageau 15 Apr '15

15 Apr '15

Hello, I had an access violation issue using boost::asio::placeholders::error as parameter to boost::bind in a class that was used as type for a static class member object. I realized that the placeholders, both those in Asio and those in Bind (e.g., _1) are themselves static objects, and thus found out that my problem was due to the famous undefined order of initialization of static objects. I was able to fix my problem simply by encapsulating my static object in a function and making sure it's called only after main() has started. However, I'm still wondering, has this issue ever been discussed and any correction or alternative proposed? I couldn't find anything on the topic. On the other hand, I noticed that Asio's placeholders are initialized from functions, e.g. from <boost/asio/placeholders.hpp>: boost::arg<1>& error = boost::asio::placeholders::detail::placeholder<1>::get(); Using that function instead could be an alternative, but since it is not in the "public" namespace and is not in the library documentation, using it would not be a good idea for maintainability. Finally, is there any documentation stating the fact that placeholders such as boost::asio::placeholders::error and _1 are static? I can't find any in the Asio or Bind documentation, and I feel this is a limitation that should at least be documented. Thank you, -- Olivier Sauvageau

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Serialization of boost::shared_ptr - wrong ref. count?
by Josef Uher 15 Apr '15

15 Apr '15

Hi All, I am using serialisation of boost::shared_ptr objects. Saving/loading works fine, except that I found out that all shared_ptr objects have reference count (use_count) minimum of 2 even though they should have 1! Debugging into the boost’s code I found out that the ref. count is increased to value of 2 in “shared_ptr_helper.hpp”, line 181 where the pointer is stored inside map “m_o_sp”. This map however never gets deleted and hence the shared_ptr seems to be stored there for ever. Please, am I doing something wrong or is there a bug? How to fix this? The sample code I use is below. I would like to emphasise that I make sure the archives are deleted after being used. So it should release the resources. I am using Mac OS X 10.10.2, boost version 1.57.0 Thank you for help, Josef **************** #include <boost/iostreams/device/file_descriptor.hpp> #include <boost/iostreams/filtering_stream.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/make_shared.hpp> class SOBJ { public: friend class boost::serialization::access; virtual void SerializationHelperFcn() {} SOBJ() { std::cout << "SOBJ Constructor" << std::endl; } virtual ~SOBJ() { std::cout << "SOBJ Destructor" << std::endl; } double value=0.; template<typename Archive> void serialize(Archive &ar, const unsigned int ver) { ar & boost::serialization::make_nvp("value", value); } }; void shared_ptr_serialization_test() { boost::shared_ptr<SOBJ> out=boost::make_shared<SOBJ>(); { boost::iostreams::filtering_ostream ofs; ofs.push(boost::iostreams::file_descriptor_sink("/Users/juhe/stest.xml")); boost::archive::xml_oarchive oa(ofs); oa << boost::serialization::make_nvp("tag", out); } boost::shared_ptr<SOBJ> in=nullptr; { boost::iostreams::filtering_istream ifs; ifs.push(boost::iostreams::file_descriptor_source("/Users/juhe/stest.xml")); boost::archive::xml_iarchive ia(ifs); ia >> boost::serialization::make_nvp("tag", in); } std::cout << "out.use_count()=" << out.use_count() << std::endl; std::cout << "in.use_count() =" << in.use_count() << std::endl; } ****************

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Project linking problem with boost
by Max 15 Apr '15

15 Apr '15

Hello, The problem here relates to boost, but I'm aware it may of more general nature rather than boost specific. I had a weird problem with my project. It has a bunch of dependencies including many of the boost libraries. My platform is: Win7SP1 + VS2008SP1 + boost1.39.0. I have properly set the VC++ directories for both include and lib files pointing to the boost folder (1.39.0) and of course those for other dependencies. But I got the following message when I built the project: 1>Linking to GSL lib1>Linking to lib file: CGAL-vc90-mt.lib1>Linking to lib file: libboost_date_time-vc80-mt-1_34.lib1>Linking to lib file: libboost_regex-vc80-mt-1_34.lib I don't know why VS was attempting to link to libs of boost 1.34.0 built with VC80 (I'm using VC 90 - VS2008) Could anybody please give me some hints about this problem or where the message like "Linking to lib file: ..." came from? Thanks. Best regards, Max

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Possible to use with JNI?
by Yolanda Septiana 15 Apr '15

15 Apr '15

Hi, I really need to use Java with this library. Is it possible to use JNI on this library or do I need to convert this library to Java? I find the latter task is going to be really difficult so I hope that I can use JNI. Thank you for your help.

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boost vs std atomic sequential consistency semantics
by Isaac To 15 Apr '15

15 Apr '15

I've asked the question in stack overflow, but no luck there. I hope I will see some light here. I'd like to write a C++ object where there are many logger threads logging to a large global (non-atomic) ring buffer, with an occasional reader thread which wants to read as much data in the buffer as possible. I ended up having a global atomic counter where loggers get locations to write to, and each logger increments the counter atomically before writing. The reader tries to read the buffer and per-logger local (atomic) variable to know whether particular buffer entries are busy being written by some logger, so as to avoid using them. So I have to do synchronization between a pure reader thread and many writer threads. I sense that the problem can be solved without using locks, and I can rely on "happens after" relation to determine whether my program is correct. I've tried relaxed atomic operation, but it won't work: atomic variable stores are releases and loads are acquires, and the guarantee is that some acquire (and its subsequent work) always "happens after" some release (and its preceding work). That means there is no way for the reader thread (doing no store at all) to guarantee that something "happens after" the time it reads the buffer, which means I don't know whether some logger has overwritten part of the buffer when the thread is reading it. So I turned to sequential consistency. For me, "atomic" means Boost.Atomic, which notion of sequential consistency has a "pattern" documented <http://www.boost.org/doc/libs/1_57_0/doc/html/atomic/thread_coordination.ht…> : The third pattern for coordinating threads via Boost.Atomic uses seq_cst for coordination: If ... 1. thread1 performs an operation A, 2. thread1 subsequently performs any operation with seq_cst, 3. thread1 subsequently performs an operation B, 4. thread2 performs an operation C, 5. thread2 subsequently performs any operation with seq_cst, 6. thread2 subsequently performs an operation D, then either "A happens-before D" or "C happens-before B" holds. Note that the second and fifth lines say "any operation", without saying whether it modify anything, or what it operates on. This provides the guarantee that I wanted. All is happy until I watch the talk of Herb Sutter titled "atomic<> Weapons". What he implied is that seq_cst is just a acq_rel, with the additional guarantee of consistent atomic stores ordering. The suggestion that sequentially consistent atomic operations may be re-ordered with non-atomic operations only adds to my mystery. I turned to the cppreference.com <http://en.cppreference.com/w/cpp/atomic/memory_order>, which have similar descriptions. So my questions: 1. Does C++11 and Boost Atomic implement the same memory model? 2. If (1) is "yes", does it mean the "pattern" described by Boost is somehow implied by the C++11 memory model? How? Or does it mean the documentation of either Boost or C++11 in cppreference is wrong? 3. If (1) is "yes", but (2) is "Boost documentation is incorrect", is there any way to achieve the effect I want, namely to have guarantee that (the work subsequent to) some atomic store happens after (the work preceding) some atomic load? 4. If (1) is "no", is there any way to achieve the effect I want in C++11?

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Re: [Boost-users] Unable to build old project using boost
by Max 13 Apr '15

13 Apr '15

----- Original Message ----- From: John Maddock <jz.maddock(a)googlemail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Unable to build old project using boost Date: 2015-04-13 00:08 On 12/04/2015 15:24, Juan Ramírez wrote: It seems that boost wasn't compiled with VC++ 9. The macro BOOST_NO_RVALUE_REFERENCES is not defined, which means boost thinks the compiler supports rvalue references. Since the code is header only, how Boost was built is irrelevant - but there must be some mismatch between what Boost.Config is doing and what type_traits expects. The only thing I can think of that would cause that are either: * A really really old version of Boost.Config with a newer version of type_traits - not sure how you would manage that though, or... * You have a custom config (in boost/config/user.hpp) which is setup for a newer MSVC version. If all else fails, try with a fresh boost source tree, HTH, John. ------------------------------------------------------- Thank you very much John. I didn't changed anything of the boost installation whatsoever, except for the build itself, before that problem.I was using exactly the same thing as I did 2 yearly ago, when it worked. Now it works, for boost 1.39.0, 1.49.0 and 1.57.0. But I cannot think of anything that I did made the difference. Best regards,Max On Sat, Apr 11, 2015 at 10:33 AM, Edward Diener <eldiener(a)tropicsoft.com> wrote: On 4/11/2015 6:33 AM, Max wrote: Hi guys, This must be a trivial question, but I just couldn't sort it out. I'm compiling a old project which used to work fine. But now I received a bunch of errors (this is not a surprise because the project have a lot of other dependencies and I'm in the way of setting them up) with the first one as: c:\lib\boost_1_49_0\boost\type_traits\add_lvalue_reference.hpp(19) : error C2143: syntax error : missing ',' before '&&' I'm using Win 7 SP1 + VS 2008 with SP + boost 1.49.0 (I'm using this because I previous used this. If this works fine, I will consider migrating to the latest version) Thanks for any hints. If you are using an older version of Boost and it was working before and now it is not working, something must have changed. Try to determine what might have changed. You also need to show source code you are compiling when the error occurs. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users -- Juan :wq _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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