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[IoStreams]: bzip2_compressor not working?
by Roland Bock 14 Oct '08

14 Oct '08

Hi, does the attached program write something to stdout for anyone? It should print out the bzip2-compressed version of the string "Original". It compiles fine but prints out exactly nothing. My platform is Ubuntu 8.04 64bit, gcc 4.2.3, using boost version 1.36, and bzip2 1.0.4. Any ideas? Thanks in advance, Roland PS: The equivalent code works fine for gzip and zlib compression PPS: bzip2 itself works fine, too.

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[graph]-Minor errors in docs
by Michael Fawcett 14 Oct '08

14 Oct '08

At the bottom of this doc page: http://www.boost.org/doc/libs/1_36_0/libs/graph/doc/graph_concepts.html#sec… There are numerous add_edge() calls that are incorrect, e.g. add_edge(digraph, u, v, Weight(1.2)); >From what I can tell, these should be: add_edge(u, v, Weight(1.2), digraph); Now, I'm only using 1.35, but the 1.36 documentation for add_edge here: http://www.boost.org/doc/libs/1_36_0/libs/graph/doc/adjacency_list.html supports my guess. Thanks, --Michael Fawcett

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How to serialize class derived from standard container?
by Terdale, Shantibhushan 14 Oct '08

14 Oct '08

This could be very stupid question but I am stuck with this situation. I have class A derived from List<B> and B derived from C. How do I write Serialize method for A? See below, both options I tried are not working. Any help is appreciated. Thanks. class B : public C { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(C); } }; class A : public list<B> { public: void Append( const list<string>& rBList ); A::const_iterator FindSpecialB(const B& rB); private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(List<B>); OR ar & boost::serialization::make_nvp("AddressList", boost::serialization::base_object<list<B>>(*this)); OR ?? } };

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[thread_safe_signals][signals2] call for reviewers (review tentatively scheduled Nov 1st - Nov 10th)
by Stjepan Rajko 14 Oct '08

14 Oct '08

Hello all, The review for the Signals2 library (formerly known as thread_safe_signals - description below) submitted by Frank Mori Hess has been tentatively scheduled for Nov 1st - Nov 10th. As per a recent discussion on the review process (http://tinyurl.com/48tdjs) and after consulting with the review wizards, we would like to try something new for this review: have a number of reviewers commit beforehand to submitting a review. The goal of signing up is to ensure that there is both sufficient interest in the library, and that there will be enough reviews submitted for an informed decision on acceptance. If you are interested in this library, I encourage you to sign up now to be a reviewer (by this you commit to submitting a review preferably by the end of the review period). Of course, additional reviews from non-signed-up reviewers will also be welcome, but without enough reviewers signing up beforehand it is not clear that we should proceed with a review at this time. To sign up, please send me a reply (here or privately), and let me know whether the review period is suitable for you (we can make some adjustments if necessary). I strongly encourage participation from reviewers that would examine the library from a purely user standpoint (commenting on the interface and / or the documentation), as well as reviewers that would be willing to look into the details of the implementation (i.e., you don't have to focus on both). I you would like to sign up, please let me know by this Saturday (October 18th). About the library: -------- * The library can be downloaded from: http://www.boostpro.com/vault/index.php?&directory=thread_safe_signals (latest version is signals2-2008-10-08.zip) * Documentation is also available online: http://www.comedi.org/projects/signals2/libs/signals2/doc/html/index.html * A synopsis: The Boost.Signals2 library (formerly known as thread_safe_signals) is an implementation of a managed signals and slots system. Signals represent callbacks with multiple targets, and are also called publishers or events in similar systems. Signals are connected to some set of slots, which are callback receivers (also called event targets or subscribers), which are called when the signal is "emitted." Signals and slots are managed, in that signals and slots (or, more properly, objects that occur as part of the slots) can track connections and are capable of automatically disconnecting signal/slot connections when either is destroyed. This enables the user to make signal/slot connections without expending a great effort to manage the lifetimes of those connections with regard to the lifetimes of all objects involved. When signals are connected to multiple slots, there is a question regarding the relationship between the return values of the slots and the return value of the signals. Boost.Signals2 allows the user to specify the manner in which multiple return values are combined. * Relationship to Boost.Signals: This is a thread-safe variant of the original Boost.Signals library. There have been some changes to the interface to support thread-safety, mostly with respect to automatic connection management. The following thread offers some more details on the differences between the two implementations, as well as a plan of a phased replacement of Boost.Signals should Signals2 be accepted: http://tinyurl.com/4sqau3 [nabble] Again, if you are interested in this library, please consider signing up as a reviewer. Kind regards, Stjepan (review manager)

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Complie error: 'make_shared’ was not declared in this scope
by Michael Chen 14 Oct '08

14 Oct '08

Hi everyone I meet this error: "class.cpp:89: error: no matching function for call to 'make_shared(const boost::weak_ptr<zeitgeist::Core>&)' and the code is: *return make_shared(mCore);* I'm using gcc 4.3.1 and boost 1.36.0. I tried to solve the problem by using *shared_ptr<Core>(mCore)* but got a run-time error. Could someone help me?

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Re: [Boost-users] [boost] [thread_safe_signals][signals2] call for reviewers (review tentatively scheduled Nov 1st - Nov 10th)
by Stjepan Rajko 14 Oct '08

14 Oct '08

Hi Jeff, On Tue, Oct 14, 2008 at 6:11 AM, Jeff Flinn <TriumphSprint2000(a)hotmail.com> wrote: > > It might be more expeditious to directly paste Frank's points from his email > in the above thread. I've pasted them below. Is the intent to only review > these changes? > Thanks for pasting that in. I think any issue related to the library would be appropriate to raise during the review, even if it would apply to the current Boost.Signals library (reviews are good times to figure things out :-)). The original Boost.Signals review discussion can be found here: http://lists.boost.org/Archives/boost/2002/02/index.php I'm not sure how applicable that discussion would be now since I imagine the library has evolved quite a bit over the years, but it might be useful to revisit if we end up discussing things that apply to Boost.Signals as well as the proposed library. > Is there > any info on the cost of this thread safe implementation vs. the signals1 in > a single threaded application? > I assume that the following comparison was done for a single threaded app (using dummy_mutex), but if not I suspect the results would be an upper bound for the single threaded case: http://www.nabble.com/boost%3A%3Asignal-poor-performance-td19602422.html#a1… Best, Stjepan

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boost::asio::streambuf question
by Amit Sonawane 14 Oct '08

14 Oct '08

Hi, I am using Asio in Boost version 1.36.0 and I have a question regarding boost::asio::streambuf. Code extract: Class A { boost::asio::streambuf buf;//class member void Read() { boost::asio::async_read_until(socket, buf, boost::regex("\0101"),boost::bind(DoSomething,this,boost::asio::placehol ders::error,boost::asio::placeholders::bytes_transfered));//class function } void DoSomething(const boost::system::error_code& ec, std::size_t bytes_transferred)//class function { If(!ec && (bytes_transferred != 0)) { boost::asio::streambuf::const_buffers_type bufs = buf.data(); std::string s(boost::asio::buffers_begin(bufs),boost::asio::buffers_begin(bufs) + bytes_transferred); //Do something with the data in s; //Here I need to call async_read_until again, but buf still has the data read in the earlier call so, it calls the DoSomething handler again thus repeating //the process. Read(); } } }; My question is how do I clear the contents of buf before calling async_read_until again. I tried reading into a local variable but boost::asio::streambuf is noncopyable. Is there a better way to do what I am trying to do. Any help is greatly appreciated. Esta mensagem pode conter informação confidencial e/ou privilegiada. Se você não for o destinatário ou a pessoa autorizada a receber esta mensagem, não deverá utilizar, copiar, alterar, divulgar a informação nela contida ou tomar qualquer ação baseada nessas informações. Se você recebeu esta mensagem por engano, por favor avise imediatamente o remetente, respondendo o e-mail e em seguida apague-o. Agradecemos sua cooperação. This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, change, take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation.

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return type of boost::iostreams::stream<T>::read()
by Struebing, Axel, le-tex 14 Oct '08

14 Oct '08

I apologize, if i have missed something. Reading the documentation about boost::iostreams library I could not find the information which return type the boost::iostreams::stream's class is giving me calling read(). I searched through the headers and every read() found returns std::streamsize, which sounds reasonable to me. I was surprised, that the code below does not compile --------start code ---------- #include <boost/iostreams/stream.hpp> #include <boost/iostreams/device/file.hpp> int main(void){ boost::iostreams::stream<boost::iostreams::file_source> istr(std::string("in.pdf")); char *buffer = new char[10]; std::streamsize i = istr.read(buffer,10); return 0; } -------end code----------- and gives me: test.cpp:7: error: invalid conversion from ‘void*’ to ‘std::streamsize’ Could someone shed a light on me, please? Thanks in advance. kind regards Axel

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regression test result to html conversion
by Dirk Jagdmann 13 Oct '08

13 Oct '08

Hello Boosters, I've successfully ran the regression suite on my computer and now have a gigantic result.xml file. Is there a script or XSLT available somewhere which converts it into an easier to read txt or html file, so I can see which tests passed and failed? -- ---> Dirk Jagdmann ----> http://cubic.org/~doj -----> http://llg.cubic.org

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Representing of empty sequence
by Missing Rainbow 13 Oct '08

13 Oct '08

Hi All, I am trying to understand the implementation of mpl::vector. I have simplified greatly to help understand it. I am now trying to figure out how to represent an empty sequence. Here is what I have got: template <class T0> struct vector1 { typedef vector1 type; }; template <class T0, class T1> struct vector2 { typedef vector2 type; }; template <class T0, class T1, class T2> struct vector3 { typedef vector3 type; }; struct dummy; template <class T0 = dummy, class T1 = dummy, class T2 = dummy> struct vector; template<T0> struct vector : vector1<T0> {}; template <T0, T1> struct vector : vector2 <T0, T1> {}; template <T0, T1, T2> struct vector : vector3 <T0, T1, T2> {}; Examples: vector1<char>::type vector2<int, long>::type vector3<short, int, long>::type vector<char>::type vector<int, long>::type vector<bool, float, double>::type How to declare and make use of an empty sequence? Rgds, anna -- Flow: For Love of Water http://missingrainbow.blogspot.com/2008/09/flow-for-love-of-water.html

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