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

13 Apr '15

----- Original Message ----- From: Juan_Ramírez <juanantonio.ram(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Unable to build old project using boost Date: 2015-04-12 22:24 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. 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 Thank you. My boost was built with VC++ 9. And when add #define BOOST_NO_RVALUE_REFERENCES, other errors arose - actually, VS2008 supports rvalue references. Best regards,Max

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building 64bit boost on aix 6.1
by 임영운 13 Apr '15

13 Apr '15

hi, I'm newbie. the only one thing that I wanted to ask is building boost 64bit on aix6.1. I try it a number of times. and I failed building 64bit boost objects. It built only 32bit objects. I used this option, address-model=64. but it didn't work. would you tell me how to build boost 64bit on aix6.1 thanks read this msg. 주식회사 테미 임영운(Yeong-woon Im) 305-764 대전광역시 유성구 대학로99 충남대학교 산학연교육연구관 807호 #807, TBI Center, Chungnam University 99 Daehak-ro, Yuseong-gu, Deajeon, 305-764 Korea Home URL : http://www.temee.co.kr Tel : 042-824-7014 Fax : 042-824-7015 Mobile : 010-6266-9960

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Unable to build old project using boost
by Max 12 Apr '15

12 Apr '15

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. Best regards, Max

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Re: [Boost-users] Unable to build old project using boost
by Max 12 Apr '15

12 Apr '15

----- Original Message ----- From: Edward Diener <eldiener(a)tropicsoft.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Unable to build old project using boost Date: 2015-04-11 21:33 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 _______________________________________________ Thank you Edward, To round the culprit of the problem, I created another empty win32 console app using the appwizard.But by just adding the single line of #include <boost/algorithm/string.hpp> caused the same problem: #include "stdafx.h" #include <boost/algorithm/string.hpp> int _tmain(int argc, _TCHAR* argv[]){ return 0;} The error messages: 1>C:\Lib\Coin-3.0.0\include\boost/utility/enable_if.hpp : warning C4819: The file contains a character that cannot be represented in the current code page (936). Save the file in Unicode format to prevent data loss1>C:\Lib\Coin-3.0.0\include\boost/utility/enable_if.hpp : warning C4819: The file contains a character that cannot be represented in the current code page (936). Save the file in Unicode format to prevent data loss1>c:\Lib\boost_1_49_0\boost/type_traits/add_rvalue_reference.hpp(46) : error C2059: syntax error : '&&' Thank you. Best regards,Max

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Newbie question: Example of a simple grammar and autocompletion?
by Vidya Setlur 10 Apr '15

10 Apr '15

Hi all, I'm trying to understand how the Boost spirit parsers work. Could anyone show me a simple example of a grammar, and how autocompletion can be enabled if the input matches a particular rule in the grammar template? Thanks!

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