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

Q and Embedded Systems
by Thanh Tran 19 Mar '08

19 Mar '08

I'm new to boost and would like to know if boost can be used in embedded systems. Obviously, it'll work if the system is using derivative of Linux. What if I don't have a real OS running on the system. Can I still simply fold the source code into my project and build it? I'm sure it can be done. I'm not sure how difficult it will be. Thanks. ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

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boost serialization & module boundaries
by Christian Widmer 19 Mar '08

19 Mar '08

Hi, I'm trying to use boost to serialize a machine learning library that I'm working with. It all worked out very conveniently, but it seems now, that I have hit a dead end. I've been looking on the net but couldn't find any information that worked for me, so here we go: The problem is, that the library consists of several modules, which are dynamically linked. For instance the class KernelMachine has a field kernel of type Kernel, which is contained in a separate module (in the sense of a shared object). The following code compiles, but when I try to serialize a CKernelMachine object I get an "unregistered_class" error. (CKernel does serialize fine, when called directly) class CKernelMachine : public CClassifier { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::base_object<CClassifier>(*this); ar.register_type(static_cast<CGaussianKernel *>(NULL)); ar & kernel; std::cout << "done CKernelMachine" << std::endl; } protected: CKernel* kernel; }; I found some threads that pointed me towards BOOST_CLASS_EXPORT, but I'm not exactly sure how to use it. So my question is - is it in principle even possible to serialize across module (shared-object) boundaries. If so, how should I go about? Any pointers would be greatly appreciated. - Chris

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Boost Regex - Specify multiple expressions and formats with regex_replace?
by Jeff 19 Mar '08

19 Mar '08

Dear Regex Users: I'd like to know if it is possible to check multiple expressions and specify multiple patters within a single regex_replace statement. For example, I want to replace .html extensions with .php and replace .gif with the .srf extension Match: http://localhost/index.gif replace with: http://localhost/index.srf Match: http://localhost/index.html replace with: http://localhost/index.php Can this be done within a single regex_replace statement? Although this does not work, it demonstrates what I am trying to achieve: // trying to match either condition const boost::regex sExp("(?:^(.*/)index\.html$) | (?:^(.*/)index\.gif$)"); // trying to replace according to matched extension const std::string sRewrite("$1index.php"); std::string rewrite(const std::string& s) { return boost::regex_replace(s, sExp, sRewrite, boost::match_perl | boost::format_perl | boost::format_no_copy | boost::format_all); } int main() { string s[5] = { "http://localhost/abc.png", "http://localhost/abc.jpb", "http://localhost/index.gif", "http://localhost/hambone.srf", "http://localhost/index.html" }; for(int i = 0; i < 5; ++i) { if (rewrite(s[i])!="") { cout << rewrite(s[i]) << endl; } } return 0; } I don't know if regex_replace can be used to do this or not. Thank you, Jeff

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Boost.Interprocess Documentation
by Alexander Dong Back Kim 19 Mar '08

19 Mar '08

Hi all, Is there any document or resource that I can learn about Boost.Interprocess? I'm currently being interesting with Shared Memory stuff. Any suggestions or hints are welcomed. -- Alexander Dong Back Kim Australia +61 433 469 100 / Korea +82 10 6357 8840

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[interprocess] shared_memory_object opened or created?
by Boris 19 Mar '08

19 Mar '08

If I instantiate a shared_memory_object with open_or_create how do I know if it was opened or created? I ask as if it was created I need to create a structure in the mapped region. If it was opened though I must not create a structure (as another program created the structure before and I might overwrite data). I ran into this problem after creating a reader and writer. They exchange data using a shared_memory_object. It would be great if I could start the two programs in any order. But currently the programs don't know which one created and which one opened the shared memory. Do I miss anything or was open_or_create added for another use case? Boris

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Re: [Boost-users] [boost] Logging library review results
by John Torjo 19 Mar '08

19 Mar '08

Hi All, > I read through the submitted reviews and here is a short summary: > > Thanks to all who contributed. Now I'll know what needs to be improved - again ;) I'd like to formally ask for another review mid-end July. So, looking for a review manager - again ;) > > In the end we came to 8 negative 7 positive votes with average 4.9 grade. > Essentially opinions split right in a middle. Oh, how familiar these days ;) > > I must say this puts me in a quite a spot. The library obviously has great > potential, but quite unacceptable by many in it's current form. While > praising it's flexibility in many aspects, the reviewers expressed wide > variety of serious concerns regarding design, implementation and > documentation. > > Yup, will redo, and redo the docs as well. > The logging library submission is NOT accepted in it's current form. > > My biggest concern, as many others expressed here before, is that we do need > the logging library. So I can't be any more encouraging to John to resubmit > an updated version for review within any reasonably short time, once issues > brought during review are addressed. I am not going to list all the issues > here - you will need to look through quite detailed reviews, but I want to > emphasize most prominent ones: > > Again, I'd like to resubmit, mid-end July. > * The library would gain from clean separation of framework and solution. > What I mean here is that there should be separate > layer which defines only generic concepts and another layer for specific > solutions provided by library. My personal suggestion is to use layered > design, where each layer is more feature-rich, but more targeted. > Got it. > * Library should support wide variety of "simple cases" out of the box and > with minimal efforts required by users. *Each* usage scenario should be well > documented and supported by example. > Yes - my problem is that each person seems to have a different opinion of what "simple case". However, what I'll do is this: - have a few simple cases, and write the code for them - minimize the number of lines I write in order to meet a certain case - question: what do you think it's a reasonable number of lines, for a simple case? I'd go for 5-10 lines of code. About those simple cases : the problem is that I have my own simple cases - which might not be what you want. So, if you have your great simple case, shout! On a side-note - I'll make a couple of web pages where I'll split the work to be done. Then, you all are most welcome to comment on them. > * Library shouldn't try to be too smart. All optimizations and advanced > features should be eliminated. At least not in a review version. This > includes any kind of optimized strings or scenario based log selection. > Later on you may start adding them based on user input. > I see - ok, basically that's easier for me. So I'm down with that ;) > * I recommend to start some kind of pool for simple/common cases on the dev > list before you jump to support them. Library should clearly state that > other more advanced usage cases are supportable as well. The same > recommendation applies to the general set of supported features by the > library out of the box. > Got it. > * Macros usage should be marginally reduced. Documentation should explain > how to write them, but not force them as the only solution. > Yup, will do. > * You may consider supporting lambda like API an one of the alternatives. > That should be possible. > * Unicode support strategy needs to be fixed > Yes, it will. > * Documentation require major revision. Obviously I can't put it as a > requirement, but my personal recommendation - drop doxigen. IMO you can't > Well, I'll think about it - however, I really love doxygen. So I guess we shouldn't blame the tool for the fact that I messed up the docs. > have professional documentation based on this format. Plus it's > unnecessarily pollute your code. Boostbook and Quickbook are much more > No offense about Boostbook: http://www.boost.org/doc/html/boostbook/getting/started.html But if getting started is so complex, I tend to not use it. > attractive solutions. Also many reviewers expressed desire for more formal > tone in user's guide and reference. (Another personal comment - where did > About the formal tone in the user's guide/reference - will do. > you find word "gather" usage as noun? I personally would prefer something > like "entry") > > Where have I used it as a noun? > Yet again I'd like to express our gratitude to the John for his efforts and > hopes that he'll be able to see this library though to the eventual success. > It has great potential. > > Thanks ;) And it'll happen ;) Best, John -- http://John.Torjo.com -- C++ expert http://blog.torjo.com ... call me only if you want things done right

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Question on BOOST_FOREACH
by Alexander Dong Back Kim 19 Mar '08

19 Mar '08

What header file should I have to include? I tried #include <boost/foreach.hpp> but g++ compile shows the following error. .... boost/foreach.hpp: No such file or directory In the source code file, it doesn't only include foreach.hpp but also many other boost headers. Why only this one is showing an error? Do I need to choose another header or something? Cheers, -- Alexander Dong Back Kim Australia +61 433 469 100 / Korea +82 10 6357 8840

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Serialization support of Unordered Containers
by brass goowy 19 Mar '08

19 Mar '08

Shalom A possibly easier to read version of this note is here - http://www.webebenezer.net/uncontainers_mar182008 I'm happy to report that we have added serialization support for the following types from the recently accepted Unordered Containers library: unordered_set, unordered_multiset, unordered_map and unordered_multimap. I recall past discussion of names for these containers. I'm of the opinion there is room for improvement in this area and Erik Wikström points out on c.l.c++ that the containers are "ordered by the hash of the key." We are also interested in supporting the Intrusive library. It would be helpful to hear if there are trends developing in the way people use that library. Brian Wood Ebenezer Enterprises www.webebenezer.net

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Re: [Boost-users] boost multiindex: trying to create a template
by Sharad Mittal 18 Mar '08

18 Mar '08

Thanks a lot Steven. That compiles fine. Do you have any online pointers/examples related to this? Sharad Steven Watanabe wrote: AMDG Sharad Mittal wrote: > I am trying to do the following in order to create a templatized data > structure which is both hashed and sequenced.. > > // typedef client_info_map::nth_index<1>::type clinfo_map_hash; > > // typedef client_info_map::nth_index<0>::type clinfo_map_list; > > * * > > This compiles fine. But when i uncomment the two index typedefs > (above), the compilation fails saying "ISO C++ forbids declaration of > `nth_index' with no type". > > Is there any other way of achieving the same result? > typedef *typename* client_info_map::*template* nth_index<1>::type clinfo_map_hash; In Christ, Steven Watanabe _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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boost multiindex: trying to create a template
by Sharad Mittal 18 Mar '08

18 Mar '08

I am trying to do the following in order to create a templatized data structure which is both hashed and sequenced.. template <class T> // class T will always have a member clientid class seq_hash_list { typedef multi_index_container < T *, indexed_by < sequenced< >, hashed_unique<member<T,nid, &T::clientid> > > > client_info_map; // typedef client_info_map::nth_index<1>::type clinfo_map_hash; // typedef client_info_map::nth_index<0>::type clinfo_map_list; public: client_info_map _clmap; }; This compiles fine. But when i uncomment the two index typedefs (above), the compilation fails saying "ISO C++ forbids declaration of `nth_index' with no type". Is there any other way of achieving the same result? Thanks, Sharad

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