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Serializing of object with map and multimap. Questions.
by B Hart 13 Nov '09

13 Nov '09

I've been having some problems storing and loading a class with a map and a multimap. The map contains values that are simple objects of another class. My questions are below. Here is also a link to the same question posted on stackoverflow. Thanks. http://stackoverflow.com/questions/1676781/boost-serializing-of-object-cont… See below a main() and two very simple classes. Then per Boost serialization (and what is shown) my questions are: 1) Does class B need the normal overloaded stream insertion operators '<<' and '>>' to be defined? Currently in my real code it doesn't have these. 2) Does class A in the store() and load() methods need to iterate through the map and multimap containers explicitly, storing/loading their key:value pairs explicitely? e.g. something like: void A::store(const char* filename){ std::ofstream ofs(filename); boost::archive::text_oarchive oa(ofs); std::map< std::string, B >::iterator it; BMap.size(); oa << BMap.size(); for( it = BMap.begin(); it != BMap.end(); it++ ){ oa << it->first; oa << it->second; } //similar for strMultimap } I assume that I don't need to do this, but am not certain. 3) Assuming class B has only the two data members shown, does it need a default contructor included explicitely? (as opposed to the implicit default constructor) 4) Does B need to have an overide for the comparison operator '>'? I assume that it doesn't since this is a very simple class. Finally, any other comments per anything that I've failed to cover is appreciated! Example code for my above questions: //includes ommitted int main() { std::string file("test.dat"); A * pA = new A; pA->store(file.c_str()); pA->fillMaps(); //release data pA->load(file.c_str()); return 0; } //includes ommitted class A { friend class boost::serialization::access; public: std::map< std::string, B > BMap; std::multimap< std::string, std::string > strMultimap; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BMap; ar & strMultimap; } void store(const char* filename){ std::ofstream ofs(filename); boost::archive::text_oarchive oa(ofs); oa << this; } void load(const char* filename){ std::ifstream ifs(filename); boost::archive::text_iarchive ia(ifs); ia >> this; } void fillMaps(){ //code to allocate B objects and put them in BMap and fill strMultimap with whatever number of key:value pairs } class B { friend class boost::serialization::access; public: std::string str; unsigned int num; B::B(void) : str("a string") , num(7) { } template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & str; ar & num; } }

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Building on Mac with Snow Leopard
by DeNigris Sean 13 Nov '09

13 Nov '09

Hi list, I downloaded 1.40.0 and started to build on my mac, but "./bootstrap.sh --help" gave me back "command not found" in Terminal. It turned out that the permissions for bootstrap.sh were wrong (executable bit not set), so I had to "chmod 755 bootstrap.sh" first. Just a heads-up if anyone else runs into this. Cheers! Sean DeNigris sean(a)clipperadams.com

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[Serialization] Serialization of function pointers
by elizabeta petreska 12 Nov '09

12 Nov '09

Hello everybody This is my first post to the list. Can I serialize C++ function pointer ? I search around and found that it could not be done ( although I am not sure ). If it can not be done, whats the explanation about it ? Thanks

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BJam scans entire disk for compilation
by Parijat Garg 12 Nov '09

12 Nov '09

Hi! I recently migrated all my C++ project compilation to BJam. While it has saved me a lot of hassles, I found that BJam takes too much time preparing for compilation. I ran an strace and found that BJam is scanning through my entire disk - perhaps looking for compilation targets. Is this a usual thing or are my compilation scripts likely to be misconfigured? Help will be much appreciated. Parijat

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[Review] We're halfway through the GGL review
by Hartmut Kaiser 12 Nov '09

12 Nov '09

Hey all, We're halfway through the GGL review (see attached review announcement) it is planned to end November 15th. Now would be a good time to send in your reviews! Regards Hartmut ------------------- Meet me at BoostCon http://boostcon.com

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[BGL] Schultes and Sanders Contraction Hierarchies Routing
by Stephen Woodbridge 12 Nov '09

12 Nov '09

Hi all, Has anyone looked at supporting Drs Schultes and Sanders Contraction Hierarchies Routing using Boost Graph? See here for more info on this: http://algo2.iti.kit.edu/english/routeplanning.php This requires lots of preprocessing of the graph, but offers 10-100 times faster performance on shortest path solutions. If Andrew, Jeremiah or others have time to look at some of the papers, I would be interested in your thoughts on supporting this or even knowing that BGL might be the wrong tool to implement this with. Thanks for any feedback you might be able to offer. Best regards, -Stephen Woodbridge

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Exceptions and throwing across module boundaries
by Josh Faust 12 Nov '09

12 Nov '09

One of the problems with exceptions that we've run into recently is throwing across module boundaries -- we hit a case where an exception thrown in one module cannot be caught as anything but a std::exception in a module compiled with different settings (same compiler -- gcc 4.2). This is of course item #62 in "C++ Coding Standards". Since we'd prefer to use exceptions rather than return codes as our error reporting mechanism, I'm currently investigating possible solutions to this. I was hoping to find something applicable boost, but it looks like boost doesn't differentiate between throwing in a header vs. throwing in a module -- for example, Boost.Thread has a few throw statements in cpp files (both in posix and win32). Is this just an issue that hasn't been enough of a problem to address? The approach I am considering is wrapping module interfaces with a translation layer which turns an exception to an error code, which is re-translated back to an exception in the header used by client code. Has anyone done anything similar? Is there something in boost like this already? (I was hoping to find something in Boost.Exception, but it does not appear to solve this situation). Thanks Josh

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[Fusion] Views of Associative Sequences
by James Knight 11 Nov '09

11 Nov '09

I'm trying to find a solution to the following problem. If I have an associative sequence such as a fusion::set and I make a filter view of it, the view is not a model of an associative sequence and does not support the has_key and at_key functions. I can use fusion::as_set on the view to get an associative sequence again, but this doesn't really have the effect I want as it results in a set holding copies of the original data whereas the view referenced the original data. Example below. Would it be possible to create a view which supported the associative sequence interface? Any suggested alternative approaches? Thanks Nate ~~~~~~~~~~~~~~~~~ #include <boost/fusion/include/set.hpp> #include <boost/fusion/include/intrinsic.hpp> #include <boost/fusion/include/filter_view.hpp> #include <string> #include <boost/type_traits/is_arithmetic.hpp> #include <boost/mpl/placeholders.hpp> namespace fusion = boost::fusion; using boost::mpl::_; int main() { typedef fusion::set<int,double,std::string> set_t; set_t s(1,2.0,"hello"); fusion::filter_view<set_t,boost::is_arithmetic<_>> filtered_view(s); fusion::front(filtered_view) = 4; //modifies s fusion::result_of::as_set<fusion::filter_view<set_t,boost::is_arithmetic<_> > >::type filtered_set(filtered_view); fusion::at_key<int>(filtered_set) = 16; // modifies the copied data in filtered_set. }

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naming delayed variables string in boost lamdba
by Emanuele Rocci 11 Nov '09

11 Nov '09

Hi AllI am getting familiar with boost::lambda.Today I learnt about delayed variable and usage of boost::constant in lambda expression.Do you know why when I try to declare delayed variables for string like I do belowthe compiler gives me each time an error?I tried the following constant_type<const char*>::type _msg_a(constant("my msg"));constant_type<const std::string>::type _msg_b(constant("my msg"));constant_type<std::string>::type _msg_c(constant("my msg")); If I use constant( "my msg" ) inside a boost lambda expression everythingis fine but I cannot declare correctly a delayed variable.Do you know how to fix it or where I can get some details?Thanks in advanceMn _________________________________________________________________ Facile, veloce, sicuro: scarica Internet Explorer 8 per MSN http://www.microsoft.com/italy/windows/internet-explorer/msn.aspx

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[string-algo] split() input
by Igor R 11 Nov '09

11 Nov '09

The following is split() function declaration: template<typename SequenceSequenceT, typename RangeT, typename PredicateT> SequenceSequenceT & split(SequenceSequenceT &Result, RangeT &Input, PredicateT Pred, token_compress_mode_type eCompress = token_compress_off); Why the 2nd parameter (Input) is declared as a non-const reference? Is it changed by the function? The problem is that it doesn't compile (gcc 4.2) when Input is a temporary.

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[config] disabling _MSC_EXTENSIONS disables win32
by Igor R 11 Nov '09

11 Nov '09

Hello, In visualc.hpp I found the following: #if !defined(_MSC_EXTENSIONS) && !defined(BOOST_DISABLE_WIN32) # define BOOST_DISABLE_WIN32 #endif I.e., disabling MSVC-specific exnetions (/Za) disables also WIN32, which, in turn, leads to undefined BOOST_WINDOWS. So if I try to compile my project with /Za, nothing compiles, because there're lot of places where BOOST_WINDOWS is used to select platform-dependant implementation (eg., in ASIO). But if I understand correctly, the purpose of disabling MSVC *language* extenstions is to ensure that the code is portable & standard-complient. So it seems to be incorrect to imply from this BOOST_DISABLE_WIN32. Am I wrong? Thanks.

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doubt on lambda expression
by Emanuele Rocci 11 Nov '09

11 Nov '09

Hi AllI started playing with boost::lambda and I need some help or some clarification about itor some hint to better understanding how does it work. I have this piece of code using namespace boost::lambda;using boost::lambda::var; int main(int argc, char** argv) { std::vector< int > myList; myList.push_back(100); myList.push_back(200); int interval = 20; std::for_each( myList.begin(), myList.end(), ( std::cout << "value: " << _1 << "\n", std::cout << "interval: " << var( interval ) << "\n", var( interval )++ ));} I understood that writing a lambda expression would be a substitutefor writing a functor. I expected the following result value: 100interval: 20value: 200interval: 21 Instead I had the following intervalfirst value: 1002020021 Why the strings "interval" and "first" are not written for each value and how can I achieve this?Kind RegardsMn _________________________________________________________________ Più di 30 Web Radio: le trovi su Messenger http://www.messenger.it/radioMessenger.aspx

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Thread Checking Tools
by Alexander Gray II 11 Nov '09

11 Nov '09

Hi, What thread checking tool (if any) is being used to ensure the boost threading model is doing the right thing? I'm currently evaluating various tools, and non of them really support this threading model. For instance, when I run the Boost threading examples through Intel Thread Checker, I get a bunch of "errors" from the tool. Someone else ran across this, and Intel's response was pretty much "we don't support Boost Threading Model": http://software.intel.com/en-us/forums/intel-parallel-studio/topic/68875/ along with same response from Microsoft CHESS: http://social.msdn.microsoft.com/Forums/en-US/chess/thread/3be2348f-661a-4f… I evaluated "helgrind" and "drd", but our suppression files were getting so large, the poor tool couldn't handle it. Any ideas how I can verify our application is truly thread safe if we use Boost? Thanks, -alex-

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Rading data from streambuf
by Lloyd 11 Nov '09

11 Nov '09

Hi, How can we read data from a streambuf? I am using boost asio. My code is as follows- boost::asio::streambuf stream; boost::asio::async_read_until(Socket, stream,string("\r\n"), boost::bind(&TCPConnection::HandleRead, shared_from_this(), boost::asio::placeholders::error)); .... .... How can i get the data from "stream" as a "char *buffer" or as a "string" Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

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concatenate strings?
by pedro chaparro 11 Nov '09

11 Nov '09

hi, i'm wondering if there is some function into boost to concatenate several strings to have just a long one? thanks -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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Constructing a shared pointer from a const pointer
by veerus 11 Nov '09

11 Nov '09

Hi All, I have been in trouble for a day solving this seemingly simple problem - constructing shared_ptr<X> from const X& without copying the X object. The programming logic does not allow me to construct the shared_ptr like this: SX x = SX( new X( x ) ); Consider the following piece of code: void foo( const X& x ) { typedef shared_ptr<X> SX; SX px = SX( &x ); bar( px ); } The compiler gives the following error: In shared_ptr.hpp at line 184: 'initializing' cannot convert from 'const X *' to 'X*'. Please suggest any procedure to solve this problem. -- View this message in context: http://old.nabble.com/Constructing-a-shared-pointer-from-a-const-pointer-tp… Sent from the Boost - Users mailing list archive at Nabble.com.

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BGL - parallel/distributed
by Ondrej Sluciak 11 Nov '09

11 Nov '09

Does anybody know how to use the functions in graph/parallel and graph/distributed? I couldn't find any references in documentation to parallel/distributed processing in graph lib, though there is obviously such functionality. Is it the same implementation as in Parallel BGL project (http://www.osl.iu.edu/research/pbgl/)? I must say that the documentation of graph library desperately needs an update.

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[Asio] Is shared_ptr with async_send_to ok?
by Dylan Klomparens 11 Nov '09

11 Nov '09

I'm using a UDP socket to send data asynchronously. I know I need to preserve the data in a buffer until the async write is complete. Can I use a shared_ptr to accomplish this? Basically, my question is, will async_send_tokeep a copy of my shared_ptr so that the data doesn't get deleted? Do I need to use a particular overload of the boost::asio::buffer function to ensure that a copy of the shared_ptr is stored? Here is an example: boost::asio::streambuf Buffer; // ... buffer is filled with data ... int BufferSize = Buffer.size(); boost::shared_ptr<unsigned char> SharedBuffer(new unsigned char [BufferSize]); Buffer.sgetn(*SharedBuffer, BufferSize); Buffer.consume(BufferSize); Socket.async_send_to(boost::asio::buffer(*SharedBuffer, BufferSize), DestinationEndpoint, boost::bind(&MyClass::OnPacketSent, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); // Shared buffer goes out of scope here, immediately!

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Boost.Asio: "End of file" when receiving data
by tiredashell 11 Nov '09

11 Nov '09

In addition to the "parameter is incorrect" error which I inquired about earlier (and remains unsolved), I am getting "End of file" sometimes when I attempt to receive data such as in the code below. Please offer some guidance as to its cause, because there is absolutely no documentation on what either of these errors mean. char reply[1024]; boost::system::error_code error; size_t reply_length = s.receive(boost::asio::buffer(reply, 1024), 0, error); if (error) cout << error.message() << endl;

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running a server "in background mode" ??
by pedro chaparro 11 Nov '09

11 Nov '09

Hi, i need to use a server inside of other code application, i take the example from http://www.boost.org/doc/libs/1_40_0/doc/html/boost_asio/tutorial/tutdaytim… and it works but the server stay in listening mode and there is other code after that i'd like continue executing, is possible tu run the server let's say like in a background mode? thanks -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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[inteprocess] Use of duration for the message_queue timed functions
by Achal Shah 10 Nov '09

10 Nov '09

A suggestion for the message_queue class is to overload timed_send and timed_receive so that they can accept a duration (say in milliseconds). I believe currently they work on an absolute time being reached. Thanks, - Achal.

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Two questions on boost::function
by CHRISTOPHE KOUDELLA, CITADEL INVESTMENT G 10 Nov '09

10 Nov '09

Hi, I am hopng to get some help from boost::function users on two questions I have. First, is it possible to extract the underlying functor out of a function? The reason for this is that it is useful to have the boost::function abstraction to move around functors in a generic fashion, but the interface is obviously limited to operator(), so being able to extract the underlying class out of a boost::function would be useful. I am thinking mostly about applied math applications in which functions are defined by more than an operator, whence the interface of boost::function is sometimes insufficient. Second, I was looking to implement a "function algebra" for boost::function (of a given arity, for a start). This algebra would implement sum, difference, product, composition, etc... operations on a pair of like boost::functions. In a template implementation in order to implement the operator() of the result boost::function, I need to access the result type and the argument types of the boost::functions being operated on. So, suppose I want to implement a product operation on a pair of template functors, then in order to define the operator() of the product of the functors, I need the result and argument types. Does boost::function make these types available as some typedefs? Does what I say make at all sense or would you proceed entirely differently in order to define such operations on boost::function? Thanks for any input, CK

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Boost.Asio: "The parameter is incorrect" when assigning native socket
by tiredashell 10 Nov '09

10 Nov '09

The error in the subject line occurs when attempting to assign a native socket to a Boost.Asio socket. I realize it's not very helpful since I'm not explaining where I am getting nativeSocket, but I was hoping someone let me know in general the cause of such an error, since there doesn't appear to be any documentation on it. I am almost positive that it is a valid socket, and its integer value is normally around 740. boost::asio::io_service ioserv; boost::asio::ip::tcp::socket s(ioserv); boost::system::error_code error; s.assign(boost::asio::ip::tcp::v4(), nativeSocket, error); if (error) cout << error.message() << endl;

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at_thread_exit() never getting called
by cowwoc 09 Nov '09

09 Nov '09

Hi, I am registering boost::this_thread::at_thread_exit() against one of my threads. When the main thread exits using "return 0" the at_thread_exit hook never gets invoked. Is this normal? Is there a way to hook the main thread shutting down? Thanks, Gili -- View this message in context: http://www.nabble.com/at_thread_exit%28%29-never-getting-called-tp26053513p… Sent from the Boost - Users mailing list archive at Nabble.com.

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getting shape of numpy array
by TheLonelyStar 09 Nov '09

09 Nov '09

Hi, I am trying to interaface a numpy array using boost::python::numeric::array. void function(numeric::array& a) { tuple shape=extract<tuple>(a.getshape()); double x; int i,j; for(i=0;i<shape[0];++i) for(j=0;j<shape[1];++j) x=extract<double>(a[make_tuple(i,j)]); } Now I had to add numeric::array::set_module_and_type("numpy", "ndarray"); to the module, hope that was correct. When I call this function in python, I get: AttributeError: 'numpy.ndarray' object has no attribute 'getshape' What is the correct way to do it? Thanks! Nathan -- View this message in context: http://old.nabble.com/getting-shape-of-numpy-array-tp26275771p26275771.html Sent from the Boost - Users mailing list archive at Nabble.com.

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