June 2008 - Boost-users - lists.preview.boost.org

DateTime: Request for additional time_duration methods
by Peter Klotz 27 Jun '08

27 Jun '08

time_duration in Boost 1.35.0 has an is_negative() method. I need exactly the opposite: time_duration td; while (td.is_positive()) { // reduce td in some way } I am aware, that I can use td.ticks()>0, but since is_negative() already exists, it would be nice to have also the following methods for completeness and symmetry: bool time_duration::is_positive() const bool time_duration::is_zero() const So for all non special value time_duration instances one of the above methods would return true, the other two false. Best regards, Peter.

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Obtain Locale Langage... more precisely LCID
by Germain BARRET 26 Jun '08

26 Jun '08

What is good way to obtain the locale settings of the system ? I've seen that test_locale.cpp is stored in regress... so if it is deprecated, what is the up to date method ? For example if I want to obtain the LCID (codes in 2 parts giving locale language) what can I use ? I don't want to treat numbers, money or so what.. but only get langage !!! Can I do it with boost ?

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[statechart] history transitions make state-local-storage "un-cool"
by Mick Hollins 26 Jun '08

26 Jun '08

Apologies if this has been discussed before, but I couldn't find any mention of it: I am currently using the history facility of boost::fsm. I've discovered that when I re-enter a state, X, via a history transition I don't actually re-enter the same instance of X that I was in before, but instead enter a newly constructed instance of X. I just checked the UML spec regarding history transitions and it says that "Any necessary entry actions are performed", so given that boost::fsm uses constructors to represent entry actions I guess a new instance of X has to be constructed to ensure UML compliance. My actual concern is the effect this has on the "coolness" of state-local-storage (see http://boost-sandbox.sourceforge.net/libs/statechart/doc/faq.html#Whats_so_…) It seems to me that state-local-storage, which I agree is generally cool, is particularly un-cool (and bug-inducing) in the presence of history transitions. I'm not sure what a good alternative is, but just thought I'd raise the discussion. cheers, mick PS: does the history facility display the same semantics in boost::statechart? I plan to move to statechart real soon now ...

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[program_options] does collect_unrecognized work for config files?
by Marty Fried 26 Jun '08

26 Jun '08

I've got program_options working for a program that has a configuration file. Aside for some program options, the file contains one or more aliases that the user defines for a server/port value, and we don't know what the alias might be until they run the program; then we search for the alias and use its value. I seems like the collect_unrecognized function would be convenient for us, but I can't seem to make it work. I passed it the parsed_options.options member, and I can see the values in there, with the string_key set correctly, and the value set correctly, and the unregistered flag set to true. But the string array result is empty. My code looks something like this: parsed_options parsed = parse_config_file(ifs, options_desc, true); vector<string> unregistered = collect_unrecognized(parsed.options, exclude_positional); What would really be convenient would be a flag to allow the unrecognized entries to be added to the map, so then, when the user enters the alias, I could just retrieve that entry from the map. Should this work for a config file? If so, what might I be doing wrong? And if not, any suggestions for how I might get it to work, aside from just parsing the file again? Thanks for your help, -- Marty Fried Senior software engineer Aldon http://www.aldon.com

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Boost::Multi_array performances
by Joel FALCOU 26 Jun '08

26 Jun '08

Hello, is there tests or references that deals with access speed to multi-array elements ? Thanks in advance -- Joel FALCOU Research Engineer @ Institut d'Electronique Fondamentale Université PARIS SUD XI France

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boost lambda problems
by Olaf Peter 26 Jun '08

26 Jun '08

Hi, the following code crashs: #include <boost/cstdint.hpp> #include <boost/lambda/lambda.hpp> #include <boost/lambda/algorithm.hpp> #include <cstring> // memset #include <iostream> union block { char buffer[512]; int integer[128]; }; std::size_t sum( block* blk ) { using namespace boost::lambda; std::size_t sum = 0; std::for_each( &blk->buffer, &blk->buffer + sizeof( blk->buffer ), sum += *_1 ); return sum; } int main() { using namespace boost::lambda; block blk; std::memset( &blk.buffer, '1', sizeof( blk.buffer ) ); std::for_each( &blk.buffer, &blk.buffer + sizeof( blk.buffer ), std::cout << *_1 << '\n' ); std::cout << sum( &blk ) << std::endl; } I'm not sure for the iterator initialization - maybe this fails. I did not wrote C style iterators for a long time and forgot this obviously. What's up here? The goal is the get the sum of the chat buffer. Do I have to protect the sum variable in function sum? Thanks, Olaf

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boost shared_ptr and parent child relation ships
by gast128 26 Jun '08

26 Jun '08

Dear all, maybe this an off-topic issue, because it does not directly relate to shared_ptr and is more related to life time of objects and their validity during construction and destruction. There were the following issues: 1) childs validity depends on availability of parent and vise versa 2) in ctor one can not use the shared_from_this() 3) in destructor of the child the parent shared_ptr was inaccesible ad 1) the doc's are clear: you can not make a cycle in shared_ptrs between parent -> child and child -> parent. Thus now we use a weak_ptr for child -> parent, but actually the child can not exist without parent. So if one shares a child through a shared_ptr, a hypothetical situation could exist that its parent get destroyed, but a child lifes on (in an invalid state due to missing parent) because a client has requested it. ad 2) this is quite unhandy, since I thought it would be handy to let the parent create the childs passing itself. I think this can only be solved by two way construction. This may well turn out to be a fundamental problem. Consider two classes A and B which are associated with each other. Object of class A is valid when it is valid itself and when its associated object of class B is valid. When A gets changed it is temporalily invalid. It updates first B, but if B asks services from A during that call, it asks an invalid object. Reversing the order may help, but A may have to update itself again after it calls B. For two related classes it can be overseen, but of course real life applications have 1000 or more classes. Btw to some extend Bertrand Meyer's book touches this subject, but he only mentions the problem within a class (with public and private members). ad 3) the destructor of the child needed the parent to call another class. However the parent was inaccessible because it was destroyed itself. This is of course also a fundamental problem because when an object gets destroyed not all of its members may be valid (the parent object is in an invalid state), so calling the parent at that time was questionable too. The real problem was that it needed form the parent its parent which was still valid, solutions are obvious (but ugly) Sample code: struct Child; struct Parent; struct Child { Child(boost::shared_ptr<Parent> ptrParent) { m_ptrParent = ptrParent; } ~Child() { boost::shared_ptr<Parent> ptrParent = m_ptrParent.lock(); if (ptrParent) { //never come here } } boost::weak_ptr<Parent> m_ptrParent; }; struct Parent : public boost::enable_shared_from_this<Parent> { Parent() { //won't work: //m_ptrChild.reset(new Child(shared_from_this())); } boost::shared_ptr<Child> m_ptrChild; }; void TestParentChild() { boost::shared_ptr<Parent> ptrParent(new Parent); ptrParent->m_ptrChild.reset(new Child(ptrParent)); } wkr, me

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[Serialization] OpenSUSE 11.0 / g++ 4.3.1 issues
by Ruediger Berlich 26 Jun '08

26 Jun '08

Hi there, when trying to compile Boost 1.35 on a vanilla OpenSUSE 11.0 system (which runs g++ 4.3.1), the serialization library fails to compile. The error messages are shown at the end of this mail. I did not find any corresponding reports on the mailing lists. Is this a known problem ? The serialization library seems to properly build in the current trunk version (as of June 26). Note, though, that I didn't test its functionality. The iostreams library fails to build in the trunk version, which I assume is due to the beta status. Best Regards, Ruediger P.S.: BTW: Is there some more or less automated way in which I can contribute to platform tests ? I.e., I'd just like to download a beta version of a new release, build it in my environment and let the build system deal with the specifics of reporting failures. OpenSUSE seems to frequently have problems with Boost, so this might be worth it. /************************************************************************/ Serialization-related error messages, Boost 1.35 on vanilla OpenSUSE 11.0 ------------------------------------------------------------------------- ...found 3940 targets... ...updating 4 targets... gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_iarchive.o In file included from libs/serialization/src/polymorphic_iarchive.cpp:18: ./boost/archive/polymorphic_iarchive.hpp:88: error: ‘virtual void boost::archive::polymorphic_iarchive_impl::load(int64_t&)’ cannot be overloaded ./boost/archive/polymorphic_iarchive.hpp:84: error: with ‘virtual void boost::archive::polymorphic_iarchive_impl::load(long int&)’ ./boost/archive/polymorphic_iarchive.hpp:89: error: ‘virtual void boost::archive::polymorphic_iarchive_impl::load(uint64_t&)’ cannot be overloaded ./boost/archive/polymorphic_iarchive.hpp:85: error: with ‘virtual void boost::archive::polymorphic_iarchive_impl::load(long unsigned int&)’ "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -fPIC -pthread -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_iarchive.o" "libs/serialization/src/polymorphic_iarchive.cpp" ...failed gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_iarchive.o... gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_oarchive.o In file included from libs/serialization/src/polymorphic_oarchive.cpp:18: ./boost/archive/polymorphic_oarchive.hpp:86: error: ‘virtual void boost::archive::polymorphic_oarchive_impl::save(int64_t)’ cannot be overloaded ./boost/archive/polymorphic_oarchive.hpp:83: error: with ‘virtual void boost::archive::polymorphic_oarchive_impl::save(long int)’ ./boost/archive/polymorphic_oarchive.hpp:87: error: ‘virtual void boost::archive::polymorphic_oarchive_impl::save(uint64_t)’ cannot be overloaded ./boost/archive/polymorphic_oarchive.hpp:84: error: with ‘virtual void boost::archive::polymorphic_oarchive_impl::save(long unsigned int)’ "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -fPIC -pthread -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_oarchive.o" "libs/serialization/src/polymorphic_oarchive.cpp" ...failed gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_oarchive.o... ...skipped <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>libboost_serialization-gcc43-mt-1_35.so.1.35.0 for lack of <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>polymorphic_iarchive.o... ...skipped <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>libboost_wserialization-gcc43-mt-1_35.so.1.35.0 for lack of <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>libboost_serialization-gcc43-mt-1_35.so.1.35.0... ...failed updating 2 targets... ...skipped 2 targets... Not all Boost libraries built properly.

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Re: [Boost-users] Mixing versions of boost
by dariomt＠gmail.com 26 Jun '08

26 Jun '08

Ovanes Markarian <om_boost <at> keywallet.com> writes: > > On Thu, Jun 26, 2008 at 9:35 AM, <dariomt <at> gmail.com> wrote: > [...] > > > > About versioning the boost namespace, I suppose you mean something like > > changing boost namespace to e.g. boost_1_35_0. Any thoughts on how much work > > it would take me to patch a given version of boost to do that? Is it even > > possible? > > > What I mean is: > > Version 1.34 might have a class A with one field of type int. Version > 1.35 might add to the class an additional field. What hapen if 1.34 > returns this type's instance to 1.35. And 1.35 will try to access the > additional field... > What I thought you meant was this: suppose boost namespace has a version number namespace boost_1_34_1 { // here are boost classes functions etc... } Then some boost header has a compatibility alias as in namespace boost = boost_1_34_1; User code would just use boost namespace, but now when two libraries use different versions of boost, the linker does not mix things, i.e. libA has symbols in boost_1_34_1 and libB has symbols in boost_1_35_0 As I said in my OP, no boost components are exposed in the library interface, so that should not be an issue. My question was regarding if namespace versioning was ever considered for boost, and if patching boost sources to produce it would be a lot of work or a piece of cake (with some automagic macro BOOST_VERSIONED_NAMESPACE ;). Thanks for your answers

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array deserialization problem
by michalurbanski 26 Jun '08

26 Jun '08

Hi all, I have a problem deserializing an array. With the code (1) I get a Segmenetation Fault with stacktrace (2). Any help appriciated. Kind regards, MU. ------------------------------------------------------------ Attachment (1): #include <fstream> #include <iostream> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/array.hpp> #include <boost/serialization/export.hpp> using namespace std; class Test { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(a); ar & BOOST_SERIALIZATION_NVP(b); ar & boost::serialization::make_array<float>(c, 1); } int a; int b; float* c; public: inline Test() { c = 0; } inline Test(int a, int b, float c) { this->a = a; this->b = b; this->c = new float[1]; this->c[0] = c; } inline void display() { cout << "a:" << a << endl; cout << "b:" << b << endl; cout << "*c:" << *c << endl; } }; BOOST_CLASS_EXPORT(Test) int main() { // SERIALIZE: std::ofstream ofs("filename.xml"); Test* t = new Test(1, 2, 3.3); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(t); ofs.close(); // DESERIALIZE: std::ifstream ifs("filename.xml"); Test* t2; boost::archive::xml_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(t2); t2->display(); return 0; } ------------------------------------------------------------ Attachment 2: 51 std::__convert_to_v<float>() 0xb7e6bc5f 50 std::num_get<char, std::istreambuf_iterator<char, std::char_traits<char> > >::do_get() 0xb7e33c8a 49 std::istream::operator>>() 0xb7e1c9c7 48 boost::archive::basic_text_iprimitive<std::istream>::load<float>() /usr/local/include/boost-1_35/boost/archive/basic_text_iprimitive.hpp:80 0x0804e687 47 boost::archive::xml_iarchive_impl<boost::archive::xml_iarchive>::load<float>() /usr/local/include/boost-1_35/boost/archive/xml_iarchive.hpp:58 0x0804e6a9 46 boost::archive::load_access::load_primitive<boost::archive::xml_iarchive, float>() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:96 0x0804e6c4 45 boost::archive::detail::load_non_pointer_type<boost::archive::xml_iarchive, float>::load_primitive::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:339 0x0804e6de 44 boost::archive::detail::load_non_pointer_type<boost::archive::xml_iarchive, float>::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:414 0x0804e6f8 43 boost::archive::load<boost::archive::xml_iarchive, float>() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:561 0x0804e712 42 boost::archive::detail::common_iarchive<boost::archive::xml_iarchive>::load_override<float>() /usr/local/include/boost-1_35/boost/archive/detail/common_iarchive.hpp:59 0x0804e736 41 boost::archive::basic_xml_iarchive<boost::archive::xml_iarchive>::load_override<float>() /usr/local/include/boost-1_35/boost/archive/basic_xml_iarchive.hpp:81 0x0804e77a 40 boost::archive::xml_iarchive_impl<boost::archive::xml_iarchive>::load_override<boost::serialization::nvp<float> const>() /usr/local/include/boost-1_35/boost/archive/xml_iarchive.hpp:74 0x0804e7b6 39 boost::archive::detail::interface_iarchive<boost::archive::xml_iarchive>::operator>><boost::serialization::nvp<float> const>() /usr/local/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:63 0x0804e7e2 38 boost::archive::detail::interface_iarchive<boost::archive::xml_iarchive>::operator&<boost::serialization::nvp<float> const>() /usr/local/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:70 0x0804e812 37 boost::serialization::array<float>::serialize<boost::archive::xml_iarchive>() /usr/local/include/boost-1_35/boost/serialization/array.hpp:39 0x0804e86b 36 boost::serialization::access::serialize<boost::archive::xml_iarchive, boost::serialization::array<float> >() /usr/local/include/boost-1_35/boost/serialization/access.hpp:109 0x0804e89b 35 boost::serialization::serialize<boost::archive::xml_iarchive, boost::serialization::array<float> >() /usr/local/include/boost-1_35/boost/serialization/serialization.hpp:81 0x0804e8bd 34 boost::serialization::serialize_adl<boost::archive::xml_iarchive, boost::serialization::array<float> >() /usr/local/include/boost-1_35/boost/serialization/serialization.hpp:140 0x0804e8fb 33 boost::archive::detail::load_non_pointer_type<boost::archive::xml_iarchive, boost::serialization::array<float> >::load_only::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:349 0x0804e91e 32 boost::archive::detail::load_non_pointer_type<boost::archive::xml_iarchive, boost::serialization::array<float> >::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:414 0x0804e938 31 boost::archive::load<boost::archive::xml_iarchive, boost::serialization::array<float> >() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:561 0x0804e952 30 boost::archive::load_wrapper<boost::archive::xml_iarchive, boost::serialization::array<float> >() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:583 0x0804e96c 29 boost::archive::load<boost::archive::xml_iarchive, boost::serialization::array<float> >() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:589 0x0804e98e 28 boost::archive::detail::common_iarchive<boost::archive::xml_iarchive>::load_override<boost::serialization::array<float> const>() /usr/local/include/boost-1_35/boost/archive/detail/common_iarchive.hpp:59 0x0804e9b2 27 boost::archive::basic_xml_iarchive<boost::archive::xml_iarchive>::load_override<boost::serialization::array<float> const>() /usr/local/include/boost-1_35/boost/archive/basic_xml_iarchive.hpp:66 0x0804e9d4 26 boost::archive::xml_iarchive_impl<boost::archive::xml_iarchive>::load_override<boost::serialization::array<float> const>() /usr/local/include/boost-1_35/boost/archive/xml_iarchive.hpp:74 0x0804e9f6 25 boost::archive::detail::interface_iarchive<boost::archive::xml_iarchive>::operator>><boost::serialization::array<float> const>() /usr/local/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:63 0x0804ea22 24 boost::archive::detail::interface_iarchive<boost::archive::xml_iarchive>::operator&<boost::serialization::array<float> const>() /usr/local/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:70 0x0804ea52 23 Test::serialize<boost::archive::xml_iarchive>() /home/wojtek/workspaceCDT/test_serial/src/main.cpp:18 0x0804eaf9 22 boost::serialization::access::serialize<boost::archive::xml_iarchive, Test>() /usr/local/include/boost-1_35/boost/serialization/access.hpp:109 0x0804eb1b 21 boost::serialization::serialize<boost::archive::xml_iarchive, Test>() /usr/local/include/boost-1_35/boost/serialization/serialization.hpp:81 0x0804eb3d 20 boost::serialization::serialize_adl<boost::archive::xml_iarchive, Test>() /usr/local/include/boost-1_35/boost/serialization/serialization.hpp:140 0x0804eb7b 19 boost::archive::detail::iserializer<boost::archive::xml_iarchive, Test>::load_object_data() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:160 0x0804ec28 18 boost::archive::detail::basic_iarchive::load_object() 0xb7ee30bc 17 boost::archive::detail::load_non_pointer_type<boost::archive::xml_iarchive, Test>::load_standard::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:364 0x0804ed2b 16 boost::archive::detail::load_non_pointer_type<boost::archive::xml_iarchive, Test>::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:414 0x0804ed46 15 boost::archive::load<boost::archive::xml_iarchive, Test>() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:561 0x0804ed60 14 boost::archive::detail::common_iarchive<boost::archive::xml_iarchive>::load_override<Test>() /usr/local/include/boost-1_35/boost/archive/detail/common_iarchive.hpp:59 0x0804ed84 13 boost::archive::basic_xml_iarchive<boost::archive::xml_iarchive>::load_override<Test>() /usr/local/include/boost-1_35/boost/archive/basic_xml_iarchive.hpp:81 0x0804edc8 12 boost::archive::xml_iarchive_impl<boost::archive::xml_iarchive>::load_override<boost::serialization::nvp<Test> const>() /usr/local/include/boost-1_35/boost/archive/xml_iarchive.hpp:74 0x0804ee04 11 boost::archive::detail::interface_iarchive<boost::archive::xml_iarchive>::operator>><boost::serialization::nvp<Test> const>() /usr/local/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:63 0x0804ee30 10 boost::archive::detail::pointer_iserializer<boost::archive::xml_iarchive, Test>::load_object_ptr() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:303 0x0804ef27 9 boost::archive::detail::basic_iarchive_impl::load_pointer() 0xb7ee3fc4 8 boost::archive::detail::basic_iarchive::load_pointer() 0xb7ee3159 7 boost::archive::detail::load_pointer_type<boost::archive::xml_iarchive, Test*>::invoke() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:479 0x0804ffa6 6 boost::archive::load<boost::archive::xml_iarchive, Test*>() /usr/local/include/boost-1_35/boost/archive/detail/iserializer.hpp:561 0x08050000 5 boost::archive::detail::common_iarchive<boost::archive::xml_iarchive>::load_override<Test*>() /usr/local/include/boost-1_35/boost/archive/detail/common_iarchive.hpp:59 0x08050024 4 boost::archive::basic_xml_iarchive<boost::archive::xml_iarchive>::load_override<Test*>() /usr/local/include/boost-1_35/boost/archive/basic_xml_iarchive.hpp:81 0x08050068 3 boost::archive::xml_iarchive_impl<boost::archive::xml_iarchive>::load_override<boost::serialization::nvp<Test*> const>() /usr/local/include/boost-1_35/boost/archive/xml_iarchive.hpp:74 0x080500a4 2 boost::archive::detail::interface_iarchive<boost::archive::xml_iarchive>::operator>><boost::serialization::nvp<Test*> const>() /usr/local/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:63 0x080500d0 1 main() /home/wojtek/workspaceCDT/test_serial/src/main.cpp:61 0x0804c542

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