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Serialization when using virtual inheritance
by Eric 29 May '05

29 May '05

Boost version: 1.32.0 I am trying to use the serialization class to serialize data pointed to by the virtual base class. Note that the code works great if I don't use virtual inheritance off of the base class. Here is a quick run-down of the hierarchy and code: class Base { virtual void OneOfManyVirtuals() = 0; // Serialization Interface template<class Archive> void serialize(Archive &ar, const unsigned int version) { //empty } }; BOOST_IS_ABSTRACT(Base); class Derived : virtual public Base { virtual void OneOfManyVirtuals() { } // Serialization Interface template<class Archive> void serialize(Archive &ar, const unsigned int version) { //empty ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base); } } // later in the main code Base* pBase = new Derived; boost::archive::xml_oarchive oa(ofs); // doesn't work oa << BOOST_SERIALIZATION_NVP(pBase); // works oa << BOOST_SERIALIZATION_NVP(*pBase); When if fails, it fails in the oseralizer.hpp at line 419 with the comment: // convert pointer to more derived type. if this is thrown // it means that the base/derived relationship hasn't be registered I tried registering the pairs with void_cast_register, but I wasn't successful. Any real examples of how to use this method would be appreciated. So, does anyone know why the pointer to the base doesn't work when using virtual inheritance? It works find when I remove the virtual from the inheritance. Unfortunately, with the software architecture that I have, there are several cases when the virtual inheritance off of interfaces is required. Any help with the matter is greatly appreciated. -Eric

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date time library question !!
by Saurabh Sood 29 May '05

29 May '05

Hi all, i am totally new to boost but more i am feeling good and bad at same time ... good coz boost is cross-platform and powerful .. however sometimes its hard to do simple things ... Take following for instance .. ------------------------------------------------------------------------------------- using namespace boost::posix_time; ptime p = = microsec_clock::local_time(); ... ... (some calculations) ... time_duration td = microsec_clock::local_time() - p; std::cout << std::string(" Total Milliseconds: ") << td.total_milliseconds() << std::endl; // Works fine ------------------------------------------------------------------------------------- But how can the value present in td.total_milliseconds() could be put inside a std::string ? It might sound simple but i guess its tricky . ... thanks for the reply in advance. cheers saurabh

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boost::thread() calls destructor!!
by Ricky Corsi 28 May '05

28 May '05

Hello, I tried to modify the sample code from Bill Kempf for boost.thread, listing 4 that I got at the following link http://www.cuj.com/documents/s=8470/cuj0205kempf/list4.htm to embed the write function in a writeClass function-object. That is a test because in a program I need to pass a function object to one thread, and not a global function. I simply wrote this code: class writerClass { public: ~writerClass() { // for Debug std::cout << "writerClass dtor" << std::endl; } void operator() () { for (int n = 0; n < ITERS; ++n) { { boost::mutex::scoped_lock lock(io_mutex); std::cout << "sending: " << n << std::endl; } buf.put(n); } } }; and changed in the main() --> boost::thread thrd2(&writer); with --> boost::thread thrd2((writerClass())); Everything works the same, but I have the destructor of wirterClass called 4 times, when constructing thrd2!!! That's weird to me, but it's annoying because in my other program, the dtor destroys some member data, and the program crashes because of it. Why is the ~writerClass() called? is there maybe some exception thrown?? how can I solve the problem? thank you ricky P.S. if it can be useful, during the compilation I get a warning (MSVC 7.1), but I read that it can be safely ignored: warning C4275: non dll interface class "boost::noncopyable_::noncopyable" used as a base for dll interface class "boost::mutex" [...]\boost\noncopyable.hpp(22): see declaration of "boost::noncopyable_::noncopyable" [...]\boost\thread\mutex.hpp(33): see declaration of "boost::mutex"

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date serialization fails with non-standard locales
by Paolo Coletta 28 May '05

28 May '05

I'm not sure if this is a bug or if I'm misusing the library. It seems that serializing boost::posix_time_ptime fails when using non-standard locale (Windows Xp OS - vc 7.1 compiler - boost updated from CVS few days ago). As an example, try adding std::locale::global( std::locale( "en" ) ); as the first line of the testtime_serialize.cpp; this causes the test to fail when doing ia >> pt2; I tried to understand what was happening, and it seems to me that the problem is in keeping into account locale when serializing, while ignoring it while unserializing. In greg_serialize.hpp to_iso_string(d) may generate something like "2,0050527"; the method from_undelimited_string(ds) used to load the serialized date, expects a 4,2,2 format. Paolo

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Re: [Boost-users] Re: building and installing boost
by TBoafo＠aol.com 28 May '05

28 May '05

Hi Dave, 1. I dont have BOOST_ROOT defined in my environment. 2. I still get messages with loading jam files when I try C:\temp\boost_1_32_0>bjam -sBOOST_ROOT=."-sTOOLS=vc-7_1" install --------------------------------------------------------------------- skipping Boost.Python library build due to missing or incorrect configuration couldn't find Python.h in "c:/tools/python/include" You can configure the location of your python installation by setting: PYTHON_ROOT - currently "c:/tools/python" PYTHON_VERSION - The 2-part python Major.Minor version number (e.g. "2.2", NOT "2.2.1") - currently "2.2" The following are automatically configured from PYTHON_ROOT if not otherwise set: PYTHON_LIB_PATH - path to Python library object; currently "c:/tools/python/libs" --------------------------------------------------------------------- Jamfile:247: in load-jamfiles *** argument error * rule stage ( name : sources + : requirements * : local-build * ) * called with: ( include/boost-1_32 : : <locate>C:\Boost <tree-subdirs>C:\temp\ boost_1_32_0 <target>install : ) * missing argument sources C:\temp\boost_1_32_0\tools/build/v1\boost-base.jam:2306:see definition of rule ' stage' being called C:\temp\boost_1_32_0\tools\build\v1\bootstrap.jam:21: in boost-build C:\temp\boost_1_32_0\boost-build.jam:16: in module scope 3. I can't see any files as per your instructions in c:\boost. cd boost DIR compatibility\cpp_c_headers\c* DIR *.hpp *.ipp *.h *.inc 4. If I try to download a fresh boost download which version should I download for this to work with vc 7.1? Regards Theo

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serialization trouble with boost when overloading the Allocator of string
by Olivier Vanden Bos 27 May '05

27 May '05

namespace TEST{ typedef std::basic_string<char, std::char_traits <char>, TEST_Allocator<char> > string; } boost\boost\serialization\access.hpp(106) : error C2039: 'serialize' : is not a member of 'std::basic_string<_Elem,_Traits,_Ax>' with [ _Elem=char, _Traits=std::char_traits<char>, _Ax= TEST_Allocator <char> ] Looking in the string.h template<class Archive, class U, class Allocator> inline void serialize( Archive & ar, STD::basic_string<U, Allocator> & t, const unsigned int file_version what is strange is when I look at my definition of basic_string in the file xstring of .NET 2003 I found template<class _Elem, class _Traits = char_traits<_Elem>, class _Ax = allocator<_Elem> > class basic_string : public _String_val<_Elem, _Ax> Any idea ? - VDB - "LNK2019: unresolved external symbol" Olivier Vanden Bos MSN#TheVdeub(a)hotmail.com AI Programmer UBISOFT Montreal

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boost::lexical_cast and special allocator
by Olivier Vanden Bos 27 May '05

27 May '05

I just discover that there is no way to change the allocator used in the streambuf of lexical_cast. It's not a big issue, but perhaps I could be a good improvement for this simple template ? - VDB - "LNK2019: unresolved external symbol" Olivier Vanden Bos MSN#TheVdeub(a)hotmail.com AI Programmer UBISOFT Montreal

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Can you compare boost::function objects?
by Stuart Dootson 27 May '05

27 May '05

I'm not certain (from the documentation) whether see if two boost::function objects are equal (I tend to think not!). The code below doesn't compile on VC7.1, raising an error about 4 ambiguous overloads of operator== #include <boost/function.hpp> int Flip() { return 2; } int main(int,char**) { boost::function<int()> f1 = &Flip; boost::function<int()> f2 = &Flip; bool const areTheyEqual = (f1 == f2); } Can someone confirm if this should/should not compile, please? Stuart Dootson

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Re: [Boost-users] Re: building and installing boost
by TBoafo＠aol.com 27 May '05

27 May '05

Dave, How do I resolve my problem? Regards Theo

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Re: [Boost-users] Re: building and installing boost
by TBoafo＠aol.com 26 May '05

26 May '05

I copied the boost installation zip file for windows the boost_1_32 zip file to c:\temp. The zip file was then expanded to c:\temp\boost_1_32_0. If one follows the instructions for building bjam from c:\temp\boost_1_32\tools\build\jam_src\ a bjam.exe gets created in c:\temp\boost_1_32_0\tools\build\jam_src\ bin.ntx86. I dont have any boost set up in the environment path. I have copied the bjam.exe to c:\windows\system32. I then type the boost install command below as per boost building instructions for visual c++ 7 as per below. C:\temp\boost_1_32_0>bjam "-sTOOLS=vc-7_1" install Regards Theo

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