January 2011 - Boost-users - lists.preview.boost.org

Problem compiling under Codegear
by jose perez 10 Jan '11

10 Jan '11

Hello. I’m using CodeGear compiler with Boost 1.39 and Boost 1.45. In both of them I have found an error in mpl\base.hpp line 25 (typedef typename T::base type;) [BCC32 Error] base.hpp(25): E2404 Dependent type qualifier 'na' has no member type named 'base' The code is: namespace boost { namespace mpl { template< typename BOOST_MPL_AUX_NA_PARAM(T) // find in mpl\aux_\na_spec.hpp, line 152: #define BOOST_MPL_AUX_NA_PARAM(param) param = na > struct base { typedef typename T::base type; // <------- ERRORRR BOOST_MPL_AUX_LAMBDA_SUPPORT(1,base,(T)) }; BOOST_MPL_AUX_NA_SPEC(1, base) }} Help will be appreciated. Thanks!

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[mpl] resulting sequence limits
by Igor R 10 Jan '11

10 Jan '11

Hello, I've got 2 mpl::map's, both have less than 20 elements. I copy one to another, and the result has more than 20 elements. I thought that BOOST_MPL_LIMIT_MAP_SIZE macro affects only explicit definitions of maps, not result values of metafunctions, but it turns out that the above case doesn't compile -- until I #include <boost/mpl/map/map30.hpp> Is it behavior "by design", or is it a bug? Thanks.

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[Range] Adaptors
by Robert Jones 10 Jan '11

10 Jan '11

I might be asking for the impossible here, but given the lovely adaptor syntax, eg std::vector<int> vec; boost::copy( vec | boost::adaptors::reversed | boost::adaptors::uniqued, std::ostream_iterator<int>(std::cout) ); I notice it still uses the function call notation in the outermost operation( boost::copy() ), can it be written to eliminate function call syntax completely, say something like vec | boost::adaptors::reversed | boost::adaptors::uniqued | boost::adaptors::copy( std::ostream_iterator<int>(std::cout) ); or even vec | boost::adaptors::reversed | boost::adaptors::uniqued | std::ostream_iterator<int>(std::cout); Thx, - Rob.

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Boost.Regex compile error with gcc 4.6
by Nathan Ridge 10 Jan '11

10 Jan '11

Hello, boost/regex.hpp fails to compile with gcc 4.6, giving the following errors: In file included from /lib/boost/boost/regex/v4/perl_matcher.hpp:578:0, from /lib/boost/boost/regex/v4/regex.hpp:88, from /lib/boost/boost/regex.hpp:31, from test.cpp:1: /lib/boost/boost/regex/v4/perl_matcher_non_recursive.hpp: In member function ‘bool boost::re_detail::perl_matcher<BidiIterator, Allocator, traits>::unwind_short_set_repeat(bool)’: /lib/boost/boost/regex/v4/perl_matcher_non_recursive.hpp:1394:85: error: invalid use of incomplete type ‘const struct boost::regex_traits_wrapper<traits>’ /lib/boost/boost/regex/v4/regex_traits.hpp:163:8: error: declaration of ‘const struct boost::regex_traits_wrapper<traits>’ /lib/boost/boost/regex/v4/perl_matcher_non_recursive.hpp:1394:85: error: invalid type argument of unary ‘*’ (have ‘BidiIterator’) It compiles fine with gcc 4.5. Is this an issue with boost or gcc? Should I report it as a bug? Thanks, Nate.

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[Proto] Storing an Expression Template as a Data Member
by Hossein Haeri 10 Jan '11

10 Jan '11

Dear all, Is there any way I can have classes with data members of type (proto) expression templates? Here is where I get stuck: template<typename T> class MyClass { ... T expression_; }; What type should T be? If you're wondering why on earth I might need that, here is an explanation: Instances of MyClass need to store the lazy calculation they will be performing later on when enough initialisation data is available. Each instance of MyClass has its own FORMULATION for the lazy calculation in terms of the initialisation data. They need to be fed with these formulations and I thought (proto) expression templates will perhaps do the job. But, then, I don't know how to store these formulations until it's time for them to perform... TIA, --Hossein

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multi_index_container: replace() modifies my iterator
by Nicolas Rannou 10 Jan '11

10 Jan '11

Hi all, I'm pretty new in boost and I am experimenting an issue I can't understand. It looks like the usage of "replace()" modifies the iterator I am iterating on: Here is a simple example: it iterates properly if I do: Iterator it2, it3; boost::tuples::tie(it2, it3) = m_Container.get< CollectionID >().equal_range( 30 ); while( it2!= it3 ) { int time = it2->TCoord; if( time < 500 ) // we want to change the collection ID in this case { Structure tempStructure(*it2); tempStructure.CollectionID = 40; * //m_Container.get< CollectionID >().replace(it2, tempStructure); comment this line* } ++it2; } whereas if I call "replace()" the iterator value changes to "it3" then it exists the loop: Iterator it2, it3; boost::tuples::tie(it2, it3) = m_Container.get< CollectionID >().equal_range( 30 ); while( it2!= it3 ) { int time = it2->TCoord; if( time < 500 ) // we want to change the collection ID in this case { Structure tempStructure(*it2); tempStructure.CollectionID = 40; * m_Container.get< CollectionID >().replace(it2, tempStructure);* } ++it2; } the replace() method returns true. I must be missing something but after reading the documentation and some researches on the web I couldn't find the answer. Any help/explanation would be greatly appreciated, Thanks, Nicolas

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using '\0' as separator in char_separator and tokenizer classes
by kmulla＠mail.com 10 Jan '11

10 Jan '11

Hi All, I am trying to use boost::tokenizer to tokenize a string containing embedded '\0' characters. I am using boost::char_separator to specify the separator. I am not getting correct tokens when I am using '\0' as the separator. Here I am curious to know, if it is indeed possible to use '\0' as separator in boost::char_separator class. I am pretty much using the code in the example given on below link. I know my code works since I am getting correct results with different separator values. http://www.boost.org/doc/libs/1_45_0/libs/tokenizer/char_separator.htm Best, K Mulla

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[boost][Serialization] - xml-stylesheet tag not recognized
by girish hilage 08 Jan '11

08 Jan '11

Hi, I am trying to learn how to read an XML file using boost-serialization. The code snippet of a sample program is as follows : void restore_schedule(bus_schedule &s, const char * filename) { // open the archive std::ifstream ifs(filename); assert(ifs.good()); boost::archive::xml_iarchive ia(ifs); // restore the schedule from the archive ia >> BOOST_SERIALIZATION_NVP(s); } First few lines of demo.xml are as follows : <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <?xml-stylesheet type="text/xsl" href="XSLTFile.xsl"?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="6"> But this gives me below error : $ ./a.out terminate called after throwing an instance of 'boost::archive::xml_archive_exception' what(): unrecognized XML syntax If I remove the line : <?xml-stylesheet type="text/xsl" href="XSLTFile.xsl"?> from demo.xml then it works fine. Can you please let me know if there is any workaround for this problem? Currently I am using Fedora Core 13 with boost-serialization-1.41.0-7.fc13.i686. Is this case handled in latest boost release? Regards, Girish

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[signals vs. signals2] Slot connecting another slot to invoking signal
by Boris Schaeling 08 Jan '11

08 Jan '11

The Boost.Signals2 documentation at http://www.boost.org/doc/libs/1_45_0/doc/html/signals2/thread-safety.html says: "Suppose a user writes a slot which connects another slot to the invoking signal. Will the newly connected slot be run during the same signal invocation in which the new connection was made? The answer is no." I'm trying to find out what Boost.Signals has to say about it. A quick test program shows that Boost.Signals does call the newly connected slot. I'm not sure though if this is undefined behavior as connecting another slot might invalidate the iterators used by the combiner? Boris

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[serialization] polymorphic archives in dlls and pointer to derived problems
by Kolb, Jeremy 07 Jan '11

07 Jan '11

I'm having a lot of trouble getting serialization of derived classes through a base pointer working across dlls. I have the following: DLL (data_types.dll) code: stdafx.h: #pragma once #include "targetver.h" #define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers // Windows Header Files: #include <windows.h> #pragma warning(disable: 4308) #include "boost/archive/polymorphic_iarchive.hpp" #include "boost/archive/polymorphic_oarchive.hpp" #include "boost/serialization/nvp.hpp" Base.h: #pragma once #include "boost/serialization/export.hpp" class __declspec(dllexport) Base { friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int version); public: Base() {} virtual ~Base() {} int i; }; BOOST_SERIALIZATION_ASSUME_ABSTRACT(Base); // Doesn't make a difference. BOOST_CLASS_EXPORT_KEY(Base); Base.cpp: #include "stdafx.h" #include "Base.h" template<class Archive> void Base::serialize(Archive& ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(i); } BOOST_CLASS_EXPORT_IMPLEMENT(Base); template void __declspec(dllexport) Base::serialize(boost::archive::polymorphic_iarchive& ar, const unsigned int version); template void __declspec(dllexport) Base::serialize(boost::archive::polymorphic_oarchive& ar, const unsigned int version); Derived.h: #include "Base.h" class __declspec(dllexport) Derived : public Base { friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int version); public: Derived() {} Derived(int num) : j(num) {} int j; }; BOOST_CLASS_EXPORT_KEY(Derived); Derived.cpp: #include "stdafx.h" #include "Derived.h" template<class Archive> void Derived::serialize(Archive& ar, const unsigned int version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base); ar & BOOST_SERIALIZATION_NVP(j); } BOOST_CLASS_EXPORT_IMPLEMENT(Derived); template void __declspec(dllexport) Derived::serialize(boost::archive::polymorphic_iarchive& ar, const unsigned int version); template void __declspec(dllexport) Derived::serialize(boost::archive::polymorphic_oarchive& ar, const unsigned int version); My exe links against the DLL and contains the following: #include "stdafx.h" #include "boost/archive/polymorphic_xml_iarchive.hpp" #include "boost/archive/polymorphic_xml_oarchive.hpp" #include "data_types/Derived.h" #include <fstream> int _tmain(int argc, _TCHAR* argv[]) { std::ofstream f("c:\\test.xml"); boost::archive::polymorphic_xml_oarchive xml(f); Base* b = new Derived(123); xml & BOOST_SERIALIZATION_NVP(b); delete b; return 0; } When serializing this fails with unregistered_class even though I export both Base and Derived. Jeremy

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