May 2006 - Boost-users - lists.preview.boost.org

boost serialization compilation and WCHAR
by Brian Budge 10 May '06

10 May '06

Hi all - I'm running into problems building the serialization library with gcc 4.1. I tracked it down to a change in libstdc++ for gcc 4.1 from the gcc 3.x libstdc++. I'm sure there's a bug, but I'm not sure if it is a boost bug, a libstdc++ bug, or a gcc 4.1 bug. boost_1_33_1/boost/config/stdlib/libstdcpp3.hpp says: #if !defined(_GLIBCPP_USE_WCHAR_T) && !defined(_GLIBCXX_USE_WCHAR_T) # define BOOST_NO_CWCHAR # define BOOST_NO_CWCTYPE # define BOOST_NO_STD_WSTRING # define BOOST_NO_STD_WSTREAMBUF #endif and indeed, with the 4.1 compiler, neither define is defined. For 4.1 in file /usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include/g++-v4/i686-pc-linux-gnu/c++config.h I have /* Defined if vfwscanf exists. */ #define _GLIBCXX_HAVE_VFWSCANF 1 /* Defined if vswscanf exists. */ #define _GLIBCXX_HAVE_VSWSCANF 1 /* Defined if vwscanf exists. */ #define _GLIBCXX_HAVE_VWSCANF 1 /* Define to 1 if you have the <wchar.h> header file. */ #define _GLIBCXX_HAVE_WCHAR_H 1 /* Defined if wcstof exists. */ #define _GLIBCXX_HAVE_WCSTOF 1 /* Define to 1 if you have the <wctype.h> header file. */ #define _GLIBCXX_HAVE_WCTYPE_H 1 (no reference to USE_WCHAR_T) and in /usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include/g++-v3/i686-pc-linux-gnu/bits/c++config.h I have // Define if code specialized for wchar_t should be used. #define _GLIBCXX_USE_WCHAR_T 1 my fix would be one of three things: 1) in c++config.h #define _GLIBCXX_USE_WCHAR_T 2) in libstdcpp3.hpp add a test for _GLIBCXX_HAVE_WCHAR_H: #if !defined(_GLIBCPP_USE_WCHAR_T) && !defined(_GLIBCXX_USE_WCHAR_T) && !defined(_GLIBCXX_HAVE_WCHAR_H) # define BOOST_NO_CWCHAR # define BOOST_NO_CWCTYPE # define BOOST_NO_STD_WSTRING # define BOOST_NO_STD_WSTREAMBUF #endif 3) somewhere else #ifdef _GLIBCXX_HAVE_WCHAR_H #define _GLIBCXX_USE_WCHAR_T #endif What do you guys think? Brian

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Re: [Boost-users] [serialization] I can't figure out what I'm doing wrong with xml_oarchive - please help
by Manos Tsagarakis 10 May '06

10 May '06

Hello Robert, Thank you for the quick response. I'm glad you liked the title ... A) I did replace all BOOST_CLASS_EXPORT with BOOST_CLASS_EXPORT_GUID, but the problem with xml persists. It is really difficult for me to figure out what is wrong with xml, as both txt and bin versions are ok. Actually what worries me, is the possibility that the problem with xml somehow will show up in other formats too ... B) I don't use the version numbers at the moment but I added it just for future use. I actually have a couple of questions here. 1) BOOST_CLASS_VERSION has to be in the header file? Can I place it in the cpp file? 2) Please correct me If I'm wrong: I don't use BOOST_CLASS_VERSION so that all classes have version number assignment set to 0. I also don't use BOOST_SERIALIZATION_SPLIT_MEMBER for now. Later on, I add some members, so that the class version must change. I simply add BOOST_CLASS_VERSION(..., 1) and split serialize to save/load at that time. Previously saved data files are not affected as long as version info is handled correctly by my code. Is that correct? C) I avoid using templated code in CTCDataBase for as long as the core data that must be serialized evolve, in order to avoid frequently modification of the most included header file TC_database.h. That meens almost recompile all, and that takes time. Thank you for the suggestion any way. I'll keep it in mind. To be honest, I did try to use export feature of templates bug no luck ... D) I re-attach a couple of header files to this post and I kindly ask you to take a look at the implementation and tracking level for template class fem::CPropRepository implementation_level< fem::CPropRepository<T, SZ> > and tracking_level< fem::CPropRepository<T, SZ> >, and one utilization of it at the other header. Should it be so? Do I need it? And also is it possible that using this CPropRepository stuff (especially with MFC CString) breaks the xml code? E) After adding all headers of the serialize library compilation takes a lot more time. Are there any guidelines by you on that? I hope I'm not encroaching your time... Thank you again, Emmanuil Tsagarakis >> -----Original Message----- >> From: boost-users-bounces(a)lists.boost.org >> [mailto:boost-users-bounces@lists.boost.org] On Behalf Of >> Robert Ramey >> Sent: Friday, May 05, 2006 8:36 AM >> To: boost-users(a)lists.boost.org >> Subject: Re: [Boost-users] [boost-users] [serialization] >> I can't figure outwhatI'm doing wrong with xml_oarchive - >> please help >> >> LOL - I liked the title. >> >> I've taken a very quick look at your code and files. >> >> a) I'm a little suspicious of including a ":" character >> as the GUID for a class. I think that might be an issue. >> Try replacing >> >> BOOST_CLASS_EXPORT(fem::CTCSoil); >> >> with >> >> BOOST_CLASS_EXPORT_GUID(fem::CTCSoil, "fem_CTCSoil"); >> >> You'll have to double check the exact syntax. >> >> b) You've set version numbers to 1 but I don't see the >> version numbers used in the deserializations. Version >> number assignment is only necessary if you're going to >> use the version numbers and they are not equal to 0. >> >> c) A minor suggestion - not important here but interesting anyway. >> In fem_boost_serialize.cpp Use templates to shorten the code. >> >> template<class Archive> >> void CTCDataBase::boost_serialize_open(const char* filename) { >> try { >> std::ifstream ifs(filename); >> assert(ifs.good()); >> Archive ia(ifs); >> >> ia >> BOOST_SERIALIZATION_NVP(m_lstSoils); >> ia >> BOOST_SERIALIZATION_NVP(m_lstBrickWalls); >> ia >> BOOST_SERIALIZATION_NVP(CTCFooting::s_bspSoil); >> ia >> BOOST_SERIALIZATION_NVP(CTCFrame::s_bspBrickWall); >> } >> catch (const boost::archive::archive_exception& e) { >> e; >> } >> } >> >> and >> template<class Archive> >> void CTCDataBase::boost_serialize_saveconst char* filename) { >> try { >> std::ofstream ofs(filename); >> assert(ofs.good()); >> Archive oa(ofs); >> >> oa << BOOST_SERIALIZATION_NVP(m_lstSoils); >> oa << BOOST_SERIALIZATION_NVP(m_lstBrickWalls); >> oa << BOOST_SERIALIZATION_NVP(CTCFooting::s_bspSoil); >> oa << BOOST_SERIALIZATION_NVP(CTCFrame::s_bspBrickWall); >> } >> catch (const boost::archive::archive_exception& e) { >> e; >> } >> } >> >> void main() >> { >> fill_with_build_in(); >> boost_serialize_save<boost::archive::text_oarchive>("boost >> _serialize.txt"); >> boost_serialize_save<boost::archive::binary_oarchive>("boo >> st_serialize.bin"); >> boost_serialize_save<boost::archive::xml_oarchive>("boost_ >> serialize.xml"); >> >> // some time later ... >> boost_serialize_open<boost::archive::text_oarchive>("boost >> _serialize.txt"); >> boost_serialize_open<boost::archive::binary_oarchive>("boo >> st_serialize.bin"); >> boost_serialize_open<boost::archive::xml_oarchive>("boost_ >> serialize.xml"); >> } >> >> Robert Ramey >> >> TOL mtsagara wrote: >> >> Hi to all, >> >> >> >> This is my very first post to boost-users! I've been >> using a couple >> >> of boost libraries for a while (shared_ptr & bind >> mostly). Write now >> >> we are in the process of transforming a project based on MFC >> >> collections, (with objects derived from CObject), to >> STL, and doing >> >> some search for a library that will allow object >> persistence the way >> >> MFC does, the obvious solution was boost::serialize. >> As I'm a newbie >> >> in mpl style code the first impression was terrifying! >> But after >> >> reading the documentation and experimenting a lot, I >> did manage to >> >> start using boost::serialize. In fact there is no need >> to be familiar >> >> with mpl. The library is excellent - an exemplary >> work, thank you >> >> Robert Ramey! >> >> >> >> Now my problem is with xml files. I can write a couple >> of classes >> >> both in txt and binary files. But I can't write the >> very same data in >> >> xml format. I believe I followed all guidelines but I >> had no luck ... >> >> :( >> >> >> >> The scenario in pseudo code is this: >> >> >> >> >> >> >> ////////////////////////////////////////////////////////// >> /////////// >> >> / >> >> // file fem.h >> >> #include <boost/archive/...> >> >> #include <boost/serialize/...> >> >> >> >> namespace fem { >> >> >> >> class CTCBase >> >> { >> >> ... >> >> }; >> >> typedef boost::shared_ptr<CTCBase> CBSPBase typedef >> >> std::list<CBSPBase> CBSPBaseList >> >> >> >> >> >> >> >> class CTCSoil >> >> { >> >> ... >> >> }; >> >> typedef boost::shared_ptr<CTCSoil> CBSPSoil typedef >> >> std::list<CBSPSoil> CBSPSoilList >> >> >> >> >> >> >> >> class CTCBrickWall >> >> { >> >> ... >> >> }; >> >> typedef boost::shared_ptr<CTCBrickWall> CBSPBrickWall typedef >> >> std::list<CBSPBrickWall> CBSPBrickWallList >> >> >> >> >> >> >> >> // list of soils >> >> CBSPSoilList s_lstSoils; >> >> // list of Brick Walls >> >> CBSPBrickWallList s_lstBrickWalls; >> >> // initial soil for each new foundation beam (also >> contained in above >> >> list) CBSPSoil s_bspSoil; // initial brick wall on >> each beam (also >> >> contained in above list) CBSPBrickWall s_bspBrick; } >> >> >> >> BOOST_CLASS_VERSION(fem::CTCBase, 1); >> >> BOOST_CLASS_VERSION(fem::CTCSoil, 1); >> >> BOOST_CLASS_VERSION(fem::CTCBrickWall, 1); >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> ////////////////////////////////////////////////////////// >> /////////// >> >> / >> >> // file fem.cpp >> >> >> >> #include "fem.h" >> >> #include <boost/serialization/export.hpp> >> >> >> >> >> >> BOOST_IS_ABSTRACT(fem::CTCBaseObj); >> >> BOOST_CLASS_EXPORT(fem::CTCSoil); >> >> BOOST_CLASS_EXPORT(fem::CTCBrickWall); >> >> >> >> void fill_with_build_in() >> >> { >> >> ... >> >> } >> >> >> >> >> >> void main() >> >> { >> >> fill_with_build_in(); >> >> boost_serialize_save_txt("boost_serialize.txt"); >> >> boost_serialize_save_bin("boost_serialize.bin"); >> >> boost_serialize_save_xml("boost_serialize.xml"); >> >> >> >> >> >> // some time later ... >> >> boost_serialize_open_txt("boost_serialize.txt"); >> >> boost_serialize_open_bin("boost_serialize.bin"); >> >> boost_serialize_open_xml("boost_serialize.xml"); >> >> } >> >> >> >> >> >> >> >> The xml save & open functions are in file >> fem_boost_serialize.cpp >> >> >> >> I attached the 3 files produced this way. I can also >> read back txt & >> >> binary versions. I'm wondering if somebody - hopefully >> Robert Ramey! >> >> - can tell me just by examining the output files, >> where should I look >> >> for the problem. Or do I have to debug the code line >> by line and see >> >> what wend wrong? It seems something is wrong with the >> very first >> >> shared_ptr serialization . >> >> >> >> I include some - not stand alone I'm afraid - source >> code files with >> >> this message just in case someone might take a look at >> them. I can >> >> tell that during the transition period from MFC to STL >> (possibly >> >> after that too), our objects derive from MFC CObject. >> Also at the >> >> moment, we still use MFC CString and not std::string. >> I had to copy >> >> CString to std::string for the serialization to work >> properly. Could >> >> there be a conflict somewhere there? Could it be the >> order in hpp >> >> files are included? >> >> >> >> >> >> Finally I use MS Visual C++ .net 2003 and boost v1.33.1. >> >> >> >> >> >> Thank you in advanced, >> >> >> >> >> >> >> >> Emmanuil Tsagarakis >> >> >> >> >> > >> > >> > >> >> _______________________________________________ >> >> 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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Question about g++'s typeof
by Stephen Gross 09 May '06

09 May '06

I just found out about the typeof feature in g++. I'm trying to use the type returned by a boost::bind invocation. Is there any way to make the following work: =============================== struct A { int foo(); } typedef typeof(boost::bind(A::foo)) my_type; =============================== So far, g++ just seg faults on me. Am I doing something horribly wrong, or is this (more likely) not possible in the first place? Thanks, --Steve Stephen Gross Case Western School of Medicine Cleveland, OH "By Grabthar's hammer, by the sons of Worvan, you shall be avenged." - Dr. Lazarus

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Re: [Boost-users] [multi_index] Core dump in multi-index library !!
by JOAQUIN LOPEZ MU?Z 09 May '06

09 May '06

Patel Priyank-PPATEL1 ha escrito: > Hi all, > > I am getting following error in boost multi-index library. I am > using following code to add and remove procedures by id in multi > index container. Can somebody please let me know what might be > wrong here? Really appreciate your quick response on this. [...] Hello Priyank, OK, I've got some questions to ask and some things for you to check. Let's see if we nail the problem down. 1. Does this happen the first time remove_by_id() is called or after some running time? 2. When the crash happens, do you have some debugging tool which allows you to inspect the contents of the _procedure variable passed to remove_by_id()? If so, does the object look OK, or garbled? 3. Note that Procedure_Pool holds *pointers* to Procedure. Could it be, when remove_by_id() crashes, that the Procedure object pointed to by _procedure is already deleted? Check the unsubscribe() routines and all the other procedures listed in the stack trace. 4. Remember we were talking about why you cannot change directly the Procedure internal variables, but instead you have to use the updating mechanisms provided by Boost.MultiIndex, as described at: http://boost.org/libs/multi_index/doc/tutorial.html#ord_updating The original discussion was at http://lists.boost.org/boost-users/2006/04/18814.php Are you respecting this? Could it be you have inadvertently changed some procedure id by calling some member function of Procedure interface? 5. You are using hashed indices, try, just for testing purposes, replacing them with ordered indices (in principle, you will only have to change the Procedure_Hashed_Pool typedef) Rerun: does the crash still persist? Hopefully, some of thes points will shed some more light. Looking fwd to your reporting. On a side note, your code shows a Procedure_Hashed_Pool with only one index, yet you define two views on it, namely pool_ and procedure_by_id_, which are the same. This is at most superfluous, although maybe what you have sent is some reduced form of the original code. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[multi_index] Core dump in multi-index library !!
by Patel Priyank-PPATEL1 09 May '06

09 May '06

Hi all, I am getting following error in boost multi-index library. I am using following code to add and remove procedures by id in multi index container. Can somebody please let me know what might be wrong here? Really appreciate your quick response on this. // HEADER FILE #include <boost/multi_index_container.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/config.hpp> #include <boost/utility.hpp> #include <boost/shared_ptr.hpp> #include <boost/multi_index/key_extractors.hpp> #include "Procedure.h" using boost::multi_index_container; using namespace boost::multi_index; /** * Defines tag used for procedure id. */ struct procedure_id_tag { }; class Procedure_Pool: boost::noncopyable { private: /** * Type definition for multi index container. */ typedef multi_index_container< Procedure*, indexed_by< hashed_unique< tag<procedure_id_tag>, const_mem_fun<Procedure, int, &Procedure::id> > > > Procedure_Hashed_Pool; /** * Type definition for indexing based on procedure id tag. */ typedef Procedure_Hashed_Pool::index<procedure_id_tag>::type Procedure_By_Id; public: /** * Constructor. */ Procedure_Pool(): pool_(), procedure_by_id_(pool_.get<procedure_id_tag>()) { } /** * Adds specified procedure in this pool. * It will intenally used procedures id() method to index procedure. * @param _procedure Procedure to be added in this pool * @return Success (0) or Failure (-1) based on addition happened or not */ int add_by_id(Procedure * _procedure); /** * Removes procedure from this pool. * @param _procedure procedure that needs to be removed * @return Success (0) or Failure (1) based on removal happend or not */ int remove_by_id(Procedure * _procedure); /** * Retrieves procedure based on specified id. * @param _id Identifier * @return Procedure Pointer to procedure. Returns 0 if procedure not found */ Procedure * find_by_id(int _id); private: /** * Returns true if procedure is present otherwise returns false. * @param _procedure procedure that needs to found * @return true if found or false if not found */ bool find_by_id(Procedure * _procedure); /** * boost multiindex object that is associated with this pool. */ Procedure_Hashed_Pool pool_; /** * Refernece of pool that is indexed by procedure id tag. */ Procedure_By_Id &procedure_by_id_; }; // IMPLEMENTATION #include "../include/Procedure_Pool.h" int Procedure_Pool::add_by_id(Procedure * _procedure) { LD_TRACE("Procedure_Pool::add_by_id"); ACE_ASSERT(_procedure != 0); if (!find_by_id(_procedure)) { // procedure not found procedure_by_id_.insert(_procedure); // debug info ACE_DEBUG((LM_DEBUG, "Added procedure : %d \n", _procedure->id())); // return success return 0; } else { // error ACE_ERROR((LD_ERROR "%N:%l Error in adding procedure : %d \n", _procedure->id())); // return failure return -1; } } int Procedure_Pool::remove_by_id(Procedure * _procedure) { LD_TRACE("Procedure_Pool::remove_by_id"); ACE_ASSERT(_procedure != 0); if (find_by_id(_procedure)) { // procedure found procedure_by_id_.erase(_procedure->id()); ACE_DEBUG((LM_DEBUG, "Removed procedure : %d \n", _procedure->id())); return 0; } else { ACE_ERROR((LD_ERROR "%N:%l Error in removing procedure : %d \n", _procedure->id())); return -1; } } Procedure * Procedure_Pool::find_by_id(int _id) { LD_TRACE("Procedure_Pool::find_by_id"); Procedure_By_Id::iterator it = procedure_by_id_.find(_id); if (it != procedure_by_id_.end()) { ACE_DEBUG((LM_DEBUG, "%N:%l Found procedure for id: %d \n", _id)); return *it; } ACE_ERROR((LD_ERROR "%N:%l Not able to found procedure for id: %d \n", _id)); // return null return 0; } bool Procedure_Pool::find_by_id(Procedure * _procedure) { LD_TRACE("Procedure_Pool::find_by_id"); ACE_ASSERT(_procedure != 0); Procedure_By_Id::iterator it = procedure_by_id_.find(_procedure->id()); return (it != procedure_by_id_.end()); } // CORE STACK TRACE (gdb) where #0 0x00000000 in ?? () #1 0x000d0008 in _ZNK5boost11multi_index13const_mem_funI9ProcedureiXadsrS2_NKS2_2idEvEEcl ERKS2_ () #2 0x000cffa4 in _ZNK5boost11multi_index13const_mem_funI9ProcedureiXadsrS2_NKS2_2idEvEEcl IPS2_EEiRKT_ () #3 0x000cf4dc in _ZN5boost11multi_index6detail12hashed_indexINS0_13const_mem_funI9Procedu reiXadsrS4_NKS4_2idEvEEENS_4hashIiEESt8equal_toIiENS1_9nth_layerILi1EPS4 _NS0_10indexed_byINS0_13hashed_uniqueINS0_3tagI16procedure_id_tagN4mpl_2 naESH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_EES5_SH_SH_EESH _SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_SH_EESaISB_EEENS_3mp l6v_itemISF_NSN_7vector0ISH_EELi0EEENS1_17hashed_unique_tagEE5eraseEi () #4 0x00066774 in Procedure_Pool::remove_by_id () #5 0x0007a4ac in AP_TCP_Connection::unsubscribe () #6 0x0006bd5c in Access_Point::unsubscribe () #7 0x00082988 in Sample_Procedure::handle () #8 0x0007a89c in AP_TCP_Connection::handle () #9 0x0005f380 in Tcp_Handler::handle_output () #10 0xff257ca8 in ACE_Select_Reactor_Notify::dispatch_notify () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #11 0xff26f424 in ACE_TP_Reactor::handle_notify_events () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #12 0xff26f188 in ACE_TP_Reactor::dispatch_i () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #13 0xff26eff8 in ACE_TP_Reactor::handle_events () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #14 0xff254e0c in ACE_Reactor::run_reactor_event_loop () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #15 0x000f3848 in ACE_Reactor::run_event_loop () #16 0x000f37d8 in Global_Reactor::svc () #17 0xff2668dc in ACE_Task_Base::svc_run () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #18 0xff266cb0 in ACE_Thread_Adapter::invoke_i () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #19 0xff266c1c in ACE_Thread_Adapter::invoke () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #20 0xff216d50 in ace_thread_adapter () at /mot/proj/ivtools/ppatel1/ACE_wrappers/ace/String_Base.inl:32 #21 0xfe8db730 in _thread_start () from /usr/lib/libthread.so.1 #22 0xfe8db730 in _thread_start () from /usr/lib/libthread.so.1 Thanks Priyank

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boos::shmem vs vc6
by Alex 09 May '06

09 May '06

Hi Guys, I'm wondering whether shmem can be used under vc6 compiler, trying to compile expamples provided within the library package I receive a full bunch of errors looking like: boost_1_33_1\boost\shmem\detail\workaround.hpp(70) : error C2011: 'random_it<void>' : 'struct' type redefinition boost_1_33_1\boost\shmem\detail\workaround.hpp(81) : error C2011: 'random_it<void>' : 'struct' type redefinition boost_1_33_1\boost\shmem\detail\workaround.hpp(92) : error C2011: 'random_it<void>' : 'struct' type redefinition boost_1_33_1\boost\shmem\shmem_fwd.hpp(154) : error C2954: template definitions cannot nest boost_1_33_1\boost\shmem\shmem_fwd.hpp(154) : error C2951: template declarations are only permitted at global or namespace scope boost_1_33_1\boost\shmem\shmem_fwd.hpp(155) : error C2226: syntax error : unexpected type 'IndexType' boost_1_33_1\boost\shmem\shmem_fwd.hpp(156) : error C2143: syntax error : missing '>' before ';' boost_1_33_1\boost\shmem\shmem_fwd.hpp(156) : error C2059: syntax error : '<end Parse>' boost_1_33_1\boost\shmem\shmem_fwd.hpp(162) : error C2955: 'flat_map_index' : use of class template re etc... However with VC7 everything seems to be fine. Your comments and ideas are highly appreciated. Regards, Alex

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mpl, apply, placeholders
by Kiuhnm 09 May '06

09 May '06

I am just a beginner so my question could be very stupid. Please be patient. What is wrong with the following code? It should be clear enough what I am trying to do. >>> #include <iostream> #include <boost/mpl/int.hpp> #include <boost/mpl/apply.hpp> #include <boost/mpl/plus.hpp> int main() { using namespace boost::mpl; // ... typedef apply< plus< _, int_<10> >, int_<1> >::type t; std::cout << typeid(t).name() << std::endl; typedef apply< plus< _, int_<10> >, _ > t2; typedef apply< t2, int_<1> >::type res; // ??? std::cout << typeid(res).name() << std::endl; } <<< Kiuhnm -- View this message in context: http://www.nabble.com/mpl%2C-apply%2C-placeholders-t1379886.html#a3705111 Sent from the Boost - Users forum at Nabble.com.

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Re: [Boost-users] [statechart] Event handlers and state reusage
by Oliver.Kowalke＠qimonda.com 09 May '06

09 May '06

>Tim Milward wrote: >> Johan Nilsson wrote: >>> 1. For a state, is it possible to specify a method that will be >>> called when an event with no defined handlers is received? >> >> Interesting question. Can all events inherit from a common base class, >> to which a state could define a (default) reaction, and override this >> with reactions to specific event sub-classes? > >Should be possible from my point of view. Not sure how the framework would >handle that even though it sounds reasonable. It's a bit limiting though, >and should be possible have support for in the library. By default statechart ignores a event with no handlers in the statemachine. Statechart allows to catch the event by adding following function to your state_machine class: void unconsumed_event( sc::event_base const& ev) { ... } Oliver

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How to pass memory range to functions?
by Olaf van der Spek 09 May '06

09 May '06

Hi, I've got a lot of functions (compression, encryption, hashing, encoding, etc) that work on a memory range. I wrote my own class that has constructors for void*, void* void*, size_t std::string& and that automatically reinterpret_cast to unsigned char*. But I'm wondering, is there a better way to do this? Boost.Range looked appriopriate but it seemed it didn't support this scenario.

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documentation for bjam sub-variants
by Russell Hind 09 May '06

09 May '06

Can some one point me to the page that details the sub-variants (such as <runtime-link> and <threading>) etc that are available to pass to bjam when building boost. I have found the main bjam page that gives a few examples but it doesn't list all the options and their meanings. Thanks Russell

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