December 2009 - Boost-users

[graph] How to find the number of adjacent nodes
by Suresh Kumar 22 Dec '09

22 Dec '09

Hi Is there any easy method to find out the number of adjacent nodes in a graph? I am using adjacency_list with listS as parameters. Hence I i am unable to subtract the vertex iterator values returned by adjacent_vertices. Thanks suresh -- R. Suresh Kumar PhD Student, Vislab #216, Engineering II Bldg University of California, Riverside,

2 1

How to use boost::asio to implement a synchronous operation with timeouts?
by watsonsong 22 Dec '09

22 Dec '09

In the boost official documents, the example of timeouts in asio is implements by asynchronous operations and a deadline_timer. But what I want is a synchronous operation with a timeout, but I search nearly all of the reference manual and find nothing about it. In an other words, how can I used the asynchronous operations to simulate synchronous operations with timeouts. Maybe I could launch an asynchronous operation and call io_service::run_one immediately, but I don't know whether it is safe when I call io_service::run_one in a complete callback function which is call by io_service::run? Or there is any classic solution of this question. Thank you. -- View this message in context: http://old.nabble.com/How-to-use-boost%3A%3Aasio-to-implement-a-synchronous… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

storing data
by Sean Farrow 22 Dec '09

22 Dec '09

Hi: I am in need to store data. Basically I have an application, when I have 8 collumns that are named, however thee are 38 possible rows with differing nameson. I also need to store the screen co-ordinates for each column name on each row. So for example: Column 1, name Item, row 1, x 66, y 85, row 2 x 88 y 121. What is the best way of being able to store this data with boost and get access to the item name, and co-ordinates given a row and column number? Any help appreciated. Cheers Sean./

1 0

Echo server demo
by Michael Fowler 22 Dec '09

22 Dec '09

Hello. I tried using the code provided here: http://www.boost.org/doc/libs/1_41_0/doc/html/boost_asio/example/echo/block… to echo text back to a client but i haven't been successful. It seems to hang at size_t length = sock->read_some(boost::asio::buffer(data), error); what is wrong? Thanks

2 2

[Serialization] shared_ptr to const object
by elizabeta petreska 21 Dec '09

21 Dec '09

Hello I am using boost 1.38.0 How to serialize shared_ptr member which points to const object. The following compiles, but is not working i.e the restored boost_shared_ptr does not point to anything. I tried to use const_pointer_cast to cast the const away. I suspect that this is the problematic part. I think the question here is , how should I cast away the const correctly for boost::shared_ptr<const T>? #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/nvp.hpp> #include <boost/serialization/utility.hpp> #include <fstream> #include <boost/serialization/shared_ptr.hpp> class B { public: B() { } B(int a):ma(a) { } int ma; template<class Archive> void serialize(Archive & ar, const unsigned int version) { using boost::serialization::make_nvp; ar & make_nvp("ma",ma); } }; class BC { public: BC() { } BC(boost::shared_ptr<B>& t):mac(t) { } boost::shared_ptr<const B> mac; template<class Archive> void serialize(Archive & ar, const unsigned int version) { using boost::serialization::make_nvp; ar & make_nvp("mac", boost::const_pointer_cast<B> (mac)); } }; int main() { std::ofstream ofs(L"C:\\MyTest.xml"); std::ifstream ifs(L"C:\\MyTest.xml"); boost::shared_ptr<B> bb(new B(4)); BC aa(bb); { boost::archive::text_oarchive oa(ofs); oa & BOOST_SERIALIZATION_NVP(aa); } BC raa; { boost::archive::text_iarchive ia(ifs); ia & BOOST_SERIALIZATION_NVP(raa); } }

3 6

Bug using mpl with <ciso646> and MSVC?
by ebryan 21 Dec '09

21 Dec '09

Hello, I am using Spirit with some code that uses the keywords 'and', 'or', etc. MSVC (at least my version, 9.0) does not implement these keywords, but support can be added by including <ciso646>, which just has a bunch of macros, ie. "#define and &&". The problem I am running into is that when I try to compile something that uses Spirit and ciso646, I get this compiler error: boost\mpl\aux_\include_preprocessed.hpp(37) : fatal error C1083: Cannot open include file: 'boost/mpl/aux_/preprocessed/plain/&.hpp': No such file or directory The offending line in include_preprocessed.hpp is: # include BOOST_PP_STRINGIZE(boost/mpl/aux_/preprocessed/AUX778076_PREPROCESSED_HEADER) It looks like the macro 'bitand' is being expanded in here, so it tries to include '&.hpp'. Now, I think this problem has already been solved (mostly). See this archived discussion, where this problem was worked around for 'and' and 'or': http://lists.boost.org/Archives/boost/2004/05/65563.php I have checked the header files in boost/mpl and only see three more conflicts between header names and ciso646 macros: 'bitand', 'bitor', and 'not'. If someone with more expertise than myself could implement a similar workaround for these headers, I would be very grateful. Thanks, Erik -- View this message in context: http://old.nabble.com/Bug-using-mpl-with-%3Cciso646%3E-and-MSVC--tp26851153… Sent from the Boost - Users mailing list archive at Nabble.com.

1 1

Using Fusion adapted struct with mpl::is_sequence
by John Smith 21 Dec '09

21 Dec '09

Hi, I have adapted a struct to be a fusion sequence like so: struct s { uint8_t i; uint8_t j; uint8_t k; }; BOOST_FUSION_ADAPT_STRUCT( s, (uint8_t, i) (uint8_t, j) (uint8_t, k) ) which works fine. However, I pass the adapted struct to my MPL algorithm and it seems to always return false on mpl::is_sequence. If I typedef boost::fusion::fusion_sequence_tag tag in the struct, then it all works, also if I pass in a proper fusion sequence, then that works as well. I was wondering if there was a different way of doing things, I don't really want to require the tag to be typedef'ed in the structure. Thanks, Dave

4 5

Serialization of derived class in a plugin
by Jean-Charles Quillet 21 Dec '09

21 Dec '09

Hi, I've been using the boost serialization on many projects. But I can't manage to make it work on my current project. Basically, I've a main application and an abstract class located in a separate dll. The application loads dynamically plugins which defines classes derived from the abstract class. Then I'm trying to serialize a class created by a plugin using a pointer to the abstract class, I always get a "Unregistered class" exception. I've used the BOOST_CLASS_EXPORT macro in the plugins trying to make the boost serialization library aware of my classes without any success so far. Looking in the source directory and specially in the "test" directory, I've seen that what I'm trying to do is the same as the test described by the file test_dll_plugin.cpp, unfortunately, it seems the test is not compiled and I can't manage to make it link without error. So my main concern is: is this feature supposed to be working ? If not I'll have to review my design. If it does what is the magic to make it work (like how to compile test_dll_plugin.cpp or another simple working example) ? Thanks for any help, Jean-Charles

2 8

How can I create a ip::tcp::iostream from a SOCKET descriptor?
by Eric J. Holtman 21 Dec '09

21 Dec '09

I'm trying to convert my hand-rolled marshalling code into boost::serialization and boost::ip classes. My code gets handed a SOCKET handle (win XP). I have no control over this, the connection/server/client stuff is handled elsewhere, I just get the SOCKET after everything's already open. How can I create an iostream from that, so I can then use the Archive classes to send and receive objects over the socket? I understand the "harder" stuff (writing the overloads for my classes for input/output to a generic stream). I'm just stuck on finding that construction (or function) that will take an already opened SOCKET handle and wrap an iostream around it. any clues?

2 2

[serialization] "unregistered class" with 1.41, o.k. with 1.38
by Ruediger Berlich 21 Dec '09

21 Dec '09

Hi there, Consider a hierarchy of classes that is accessed through an abstract base class. The most derived class is a template which is "filled" with the basic types bool, char, boost::int32_t and double. I use typedefs of the kind "typedef GParameterT<char> GChar;" for ease of use. This is held in its own header file, in this case GChar.hpp . A corresponding GChar.cpp holds the export statement needed to register the class (or typedef in this case): #include <boost/serialization/export.hpp> BOOST_CLASS_EXPORT(Gem::GenEvA::GChar) There are also identical (except for base types) files for GDouble, GBoolean and GInt32 (holding the tell-tale typedefs and exports for the corresponding types). I'm using unit tests for my library, and there you will find code like: // Test (de-)serialization in different modes { // plain text format T gpt4(gpt0); BOOST_CHECK(gpt4.isEqualTo(gpt0)); BOOST_CHECK_NO_THROW(gpt4.fromString(gpt1.toString(TEXTSERIALIZATION), TEXTSERIALIZATION)); BOOST_CHECK(!gpt4.isEqualTo(gpt0)); BOOST_CHECK(gpt4.isSimilarTo(gpt1, exp(-10))); } // [ ... further serialization modes removed ... ] T can again be GChar, GBoolean, GDouble or GInt32 . to/fromString is a simple wrapper to the serialization calls (all happening through the base pointer). Now I have the problem that the toString/fromString throws an "unregistered class" with Boost 1.4.1, but **only** if GParameterT is fed a double or a boost::int32_t . (De-)Serialization works fine with char and bool as template parameter. With Boost 1.38, no errors occur at all, and also my production code works nicely with 1.41 (and it uses Boost.Serialization extensively). Any idea ? In any case: Thanks for a great library and have a nice christmas time and a happy new year! Best Regards, Ruediger

1 0