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shared/weak_ptr conventions?
by Niklas Wiberg 10 Dec '04

10 Dec '04

Hi, I have a question that I believe is more a matter of taste than one of functional correctness... Say that I have a model (see Basket below) that formally owns the heap-objects (see Apple below). Basket has a function that is merely a query (hasApple) and involves no ownership-changes. Also assume that there is good reason that Apple:s are allocated on the heap... On one hand, I can see how using a weak_ptr as the parameter type would signal to users that hasApple has no intention of modifying ownership of the pointed-to object. On the other hand, in order to actually use the pointee (search for it in this case), hasApple must convert the weak_ptr to shared_ptr (lock() or shared_ptr constructor), so it would seem more pragmatic to just use shared_ptr as the parameter type. class Apple; class Basket { std::vector< boost::shared_ptr<Apple> > m_contents; bool hasApple( shared OR weak_ptr<Apple> a); // no transfer ...more functions }; Is there a "good style" concensus on how to choose smart pointer type for function arguments among boost smart pointer users? Best regards, Niklas Wiberg

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[variant] BOOST_VARIANT_LIMIT_TYPES and BOOST_MPL_LIMIT_LIST_SIZE
by Christopher D. Russell 09 Dec '04

09 Dec '04

I'm trying to increase the number of bounded types stored in a boost::variant. It seems like I should be able to #define BOOST_MPL_LIMIT_LIST_SIZE in multiples of ten prior to inclusion of any boost headers but this doesn't seem to work for me. I haven't upgraded to the latest 1_32_0 release yet and am working with out-of-the-box 1_31_0 on Windows using the MS 7.1 compiler (VS .NET 2003). If for example I define BOOST_MPL_LIMIT_LIST_SIZE as: #define BOOST_MPL_LIMIT_LIST_SIZE 20 #include "my_boost_headers.h" I get an error: d:\ENCAPSULE-EXTLIB\boost\boost_1_31_0\boost_1_31_0\boost\variant\detail\make_variant_list.hpp(54) : error C2977: 'boost::mpl::list' : too many template arguments d:\ENCAPSULE-EXTLIB\boost\boost_1_31_0\boost_1_31_0\boost\mpl\aux_\preprocessed\plain\list.hpp(124) : see declaration of 'boost::mpl::list' d:\ENCAPSULE-EXTLIB\boost\boost_1_31_0\boost_1_31_0\boost\variant\detail\make_variant_list.hpp(59) : see reference to class template instantiation 'boost::detail::variant::make_variant_list<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16,T17,T18,T19>' being compiled Shouldn't this just work? What am I missing here. TIA - Chris

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Boost.Serialization link errors (VC++ 7.0)
by Ray Hilton 09 Dec '04

09 Dec '04

I get 17 link errors trying to compile a very simple example from the touturial section of the documention (what im trying to compile is listed at the end of this post verbatim). My enviorment is all default except for an include path to boost. Any solution? #include <fstream> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> class gps_position { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & degrees; ar & minutes; ar & seconds; } int degrees; int minutes; float seconds; public: gps_position(){}; gps_position(int d, int m, float s) : degrees(d), minutes(m), seconds(s) {} }; int main() { std::ofstream ofs("filename"); boost::archive::text_oarchive oa(ofs); const gps_position g(35, 59, 24.567f); oa << g; ofs.close(); std::ifstream ifs("filename", std::ios::binary); boost::archive::text_iarchive ia(ifs); gps_position newg; ia >> newg; ifs.close(); return 0; }

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Compile error of data_time
by zhengyi 09 Dec '04

09 Dec '04

boost-users: Here is a new user's letter for help: when i compile the whole boost(version_1_32_0), it show some error of data_time. the file greg_month.cpp failed. in the lexical_cast.hpp，line 126 string_type s(boost::lexical_cast<string_type>("not-a-date-time")); the compiler said : binary '>>' : no operator found which takes a right-hand operand of type_put<Config,charT,OutputIterator>::string_type' (or there is no acceptable conversion) When tracing down the error message, I found that [[date_names_put::string_type]] actually means [[std::basic_string<charT>]] and in file lexical_cast.hpp line 146 -- 168 there are right overload of operator>>. Why the compiler complain about can't find the wellformed operator? My Compiler is msvc71 and STLport-5.0-0125 was installed with it's own iostream. the cmdline is bjam "-sVC71_ROOT=D:\Program Files\Microsoft\Microsoft Visual Studio .NET 2003\Vc7" "-sSTLPORT_PATH=D:\Program Files\Programming_Tools\STLport-5.0-0125\stlport" "-sSTLPORT_5.0-0125_PATH=D:\Program Files\Programming_Tools\STLport-5.0-0125" "-sSTLPORT_VERSIONS=5.0-0125" "-sTOOLS=vc-7_1-stlport" "--prefix=D:\Program Files\Programming_Tools\Boost_1_32" install --with-date_time this problem has killed so many brain cells of mine ! 　　　　　　　　　　　　　　zhengyi 　　　　　　　　　　　　　　goodmen(a)x263.net 　　　　　　　　　　　　　　　　　2004-12-08

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Re: [Boost-users] simple regex compile error
by Brian Gaber 09 Dec '04

09 Dec '04

I tried moving <boost/regex.hpp> to be the first include statement, but got the same error. I tried the following compile statement: /usr/vacpp/bin/xlc++ -c -DNDEBUG -O3 -qstrict -qinline -qnotempinc -qfuncsect -qeh -qrtti regex.cpp -o regex -I /usr/local/include and again got the same error as before. Any other suggestions? What is the ETA of the fix you mentioned.

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Re: Unresolved symbols in regex libs on tru64 (John Maddock)
by Mark Helzer 09 Dec '04

09 Dec '04

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Boost.iostream and boost_1_32
by Giuseppe Vacanti 09 Dec '04

09 Dec '04

Hello, I'm trying to compile boost.iostream (approved but not yet included in the official distribution) with boost_1_32. First I had to replace the few occurences of apply_if with eval_if, due to a change in mpl. No probs here. Then I had to add #include<boost/io/operations.hpp> to simmetric_filter_adapter.hpp so that boost::io::{read,write,flush} can be found. But now I'm stuck with ..boost/io/operations.hpp: In static member function `static void boost::io::detail::read_impl<boost::io::input>::putback(T&, typename boost::io::char_type<T>::type)': ..boost/io/operations.hpp:107: error: incomplete type `boost::STATIC_ASSERTION_FAILURE< false>' used in nested name specifier and I do not know what the next move should be. Would anybody have a suggestion? I run with linux and g++ 3.4.1. Thanks, Giuseppe

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select_parent
by Agoston Bejo 09 Dec '04

09 Dec '04

Hi! Is there such a class in boost? What I'm thinking of is fairly simple, it could be written easily with type_traits and mpl::if_, but I prefer using the standard boost components, if they exist. select_parent<T1, T2>::type is a) T1 if T1 is T2's (direct or indirect) parent b) T2 if it is the other way round c) T1 if T1 and T2 are the same d) and generates some compiler error if T1 and T2 are not related at all. Thx, Agoston

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Boost.Serialization library link errors (VC++ 7.0)
by Ray Hilton 08 Dec '04

08 Dec '04

I get 17 link errors trying to compile a very simple example from tourorial section in the documention. This is the one (took out comments and changed some spacing to save some room here)

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Compiling boost examples
by Saqib bin Sohail 08 Dec '04

08 Dec '04

I have installed BGL on my linux machine and I was wondering, how do I compile the examples, I wanted to compile the dijkstra's example but couldn't find any make files and simply doing g++ dijkstra***.cpp doesn't do the trick. (i placed the hpp files so that the example can easily access them) Thanks -- Saqib bin Sohail University of Colorado at Boulder (303) 484 8381

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