July 2009 - Boost-users - lists.preview.boost.org

[1.35.0][OSX][iostreams] Exception thrown with utf8 filename
by Christophe Radondy 17 Feb '10

17 Feb '10

Hi, I try to do a cross-platform source code and I have this code. I compiled boost 1.35 in universal binaries on Mac OS 10.5.4 with intel platform (IMAC core 2 duo 3Ghz) The same code works on linux (Ubuntu 8.0.4 and debian) and windows platforms but on Mac OS 10.5 I have an exception in boost's libraries. We compile on universal binaries with -fexceptions options of g++ 4.0.1 (Apple). This is my code: <code> boost::filesystem::wpath unicode(L"abcdef\u0110"); boost::filesystem::ofstream file(unicode.string()); // throws Invalid Argument on Mac file << "abcdef" << endl; file.close(); <endcode/> If I do this, it works: <code> boost::filesystem::path utf8("abcdef\xC4\x90"); // \xC4\x90 == \u0110 boost::filesystem::ofstream file(utf8.string()); // works ok file << "abcdef" << endl; file.close(); <endcode/> When the ofstream is created, this function is executed and crashes when I use Unicode parameters : <code> unicode.external_file_string(); // throws uncaught exception of type boost::filesystem::basic_filesystem_error<boost::filesystem::basic_path<std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >, boost::filesystem::wpath_traits> > - boost::filesystem::wpath::to_external conversion error: Invalid argument <endcode/> Do you have any idea? Is this a known bug? Did I miss a setting? Thanks for your help. Regards, Christophe.

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[Boost] Is this library availble for 64 bit?
by Jaiswal, Usha [OS-IE] 11 Feb '10

11 Feb '10

Is there any version of Boost for 64 bit.

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[iterators][range][rangeex] range concatenation
by Dmitry Vinogradov 12 Jan '10

12 Jan '10

Is it possible with Boost (or RangeEx) to concatenate ranges? Sample usage: template <class Range> void process_range(Range const &); std::vector<foo> v = ...; std::list<foo> l = ...; process_range(concat(v, l));

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[Math/Statistical Distributions+Random] Random number generation
by Marco Guazzone 07 Jan '10

07 Jan '10

Hi all! I'm a "boost newbie" so sorry for too trivial questions. Just trying to use boost for some statistical experiments, involving statistical distribution fitting, quantile generation (for goodness-of-fit tests), random variate generation, and so on. . The "Math/Statistical Distribution" library is great and almost complete. But I'm just curious why the random number generation (provided by the "Random" lib) and this library have not been integrated. For instance, the boost::random::exponential_distribution and the boost::math::exponential_distribution are two different worlds. I think a function like this below would be very helpful: --- [snip] --- template <typename Generator, typename RealType, typename Policy> inline RealType rand(Generator& rng, const exponential_distribution<RealType, Policy>& dist) { return -1.0 / dist.lambda() * std::log(1.0-rng()); } --- [snip] --- or something similar (e.g., rand implemented as a class method) In this case only two objects are needed: * boost::random::mersenne_twister * boost::math::exponential_distribution Instead, actually I have to keep different objects. For instance, for the exponential distribution: * boost::random::exponential_distribution * boost::random::mersenne_twister * boost::random::variate_generator * boost::math::exponential_distribution Unluckely I can't use boost::math::exponential_distribution in place of boost::random::exponential_distribution since boost::random::variate_generator expects a specific interface for the distribution. Well, what is the rationale behind the choice of this separation? Do you think would be useful to provide this kind of integration? Thank you very much in advance!! Cheers -- Marco

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Newbie question
by Michael Qi 07 Dec '09

07 Dec '09

Hi, I am trying to start to learn boost. Now, I am learning the getting started guide. And try to build a boost regex program in the guide. But Visual C++ 7.1 tell me error: LINK : fatal error LNK1104: Could not open file "D:\Program.obj" Could you help me? Thank you

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[Random] uniform_01
by Robert Patterson 01 Nov '09

01 Nov '09

Hi, I was looking at the docs for the uniform_01 distribution: http://www.boost.org/doc/libs/1_39_0/libs/random/random-distributions.html#… I read the following note "Note: The current implementation is buggy, because it may not fill all of the mantissa with random bits." I do not understand the problem. I looked at the code, which does what I expect. Why is it a problem if some of the mantissa bits are not 'random'? As I understand the requirement is the real numbers are uniformly distributed; the bit patterns should not matter provided they represent numbers with the right mathematical properties. Thanks Robert Patterson http://como.cheng.cam.ac.uk/index.php?Page=People&Section=riap2

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[Boost.Test] [1.38] Automated test suie registration with muti-file-test-modules
by Greg Christopher 17 Oct '09

17 Oct '09

Hi, We are starting to expand the number of test modules and are having some growing pains. Originally we were using the "single header" variant included/unit_test.hpp file. Now we have switched to linking to the dynamic version of the boost test library and are including auto_unit_test.hpp. We have been counting on the Test Tools to automatically register suites and test cases. This still worked when we just included unit_test.hpp (instead of included/unit_test.hpp). However with multiple test modules, init_unit_test_suite is being defined in each module. I am looking for clear documentation on what to do. This seems like the closest thing: http://www.boost.org/doc/libs/1_31_0/libs/test/doc/components/unit_test_fra… However following those directions exactly when trying to use multiple test modules (in a single executable) and only one BOOST_AUTO_TEST_MAIN still results in init_unit_test_suite being multiply defined. I would like multiple test suites, although the documentation for this declares that there is a single global test suite. I apologize if this is well documented somewhere, but after an hour of googling I have to ask. Greg

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New library for RPC-calls using only boost and C++0x
by Siegfried Kettlitz 13 Oct '09

13 Oct '09

Hello boost users and developers, i'm currently writing a library for making remote procedure calls to C++ objects. The library is based on the variadic templates extension coming with C++0x (already present in GCC 4.3) in conjunction with the boost library (threads, serialization, asio). The aim is to have a library, that is easy to integrate and doesn't require additional tools. Writing it, so far, has thaught me a lot about C++, templates, variadic templates, threading, networking etc.. I post this message, because i think that this library is quite handy in situations, where a developer already uses boost libraries and wants to add some networking functionality to his/her project and the usage of variadic templates instead of additional tools is quite new. One example would be remote monitoring an application by adding a "std::string get_status()"-function to some object. Implemented as example is a chat-system with a server and clients interacting by remote calls. This example is tested with a x64-linux and win32 using the portable boost-text-serialization. Multiple clients can connect to the server via the TCP/IP-acceptor (and disconnect without crashing the system). Implemented is a console-client for text input and display and a morse client, that interacts via a digital output device (relais card), which is connected via a serial port. The serial port and the digital output driver are both also connected via the rpc-system and can be physically located on separate computers. At this point, i have the basic bits together and a working rpc-library, that needs to be cleaned, refined and extended to match the practical needs. This means, that some programs and libraries have to be written, which use the rpc-library and show its bugs and limitations. The downside of it is, that the interface of the rpc-library may change one more time until it can be considered stable. Therefore it would not be good to test it widely in libraries posing similar requirements, but to test it with a variety of possible applications and provide the implementations as examples and (regression-/unit-)tests. - One library for Measurement/Automation is already in development. - The chat-server/client exists. - A transaction based game server is under consideration. - Some distributed parallel computing application with dynamic joining/leaving of clients. Can you give me some more ideas of different applications, which are easy to implement but yet useful? What would you like to have implemented and accessible by an rpc-library? One speed measurement using local (shared memory) channels resulted in 20000 calls/s and 60000 messages/s on a 1.8GHz Opteron. Do you know how this compares to other implementations on similar hardware? The TCP/IP-channel implementation using ASIO resulted in only about 100 synchronous calls/second regardless of the payload and almost no CPU load, which suggests that ASIO somewhere "sleeps" on linux systems for a few milliseconds. This would be fixed in some future implementation. Using asynchronous calls (1000 open calls) again leads to about 10000 calls/s. I'll have a closer look on what can be merged with "channels" from the boost vault[1], but from the first look it seems that "channels" targets a much more general approach. After the first tries, i realized, that my implemention has to be very specific (e.g. templates only where necessary). So, the design approaches might be too different. After the refinement, cleanup, some testing and documenting, i'd like to publish the rpc-library (and libraries based on it) under GPL- or boost-license. Then you'll hear from me again. In future i'll probably work 2-8 hours per week on the library and use it in some projects, but there's plenty of work left to do in various regions. This will leave space for other developers who might want to use and modify it to fit their needs. Some of the harder parts that would need implementation are redundant parallel connections and advanced routing, authentication of nodes, signing of messages, encryption of payload, access restriction to objects. Please let me know if * you are interested in this library in some way * have comments * know very similar libraries or * are interested in serialization using variadic function templates. Regards, Siegfried Kettlitz --- A short introduction on the library: * "nodes" are the central parts. They contain a factory for objects, store objects and forward "messages" to objects or other nodes in the network and contain a "scheduler" for executing function calls. The nodes are connected by "channels", which forward messages between the two connected nodes. Currently there is a TCP/IPv4 implementation using ASIO and direct forwarding. * Nodes connected by channels form a network, create and monitor virtual connections between each other. The network map is used to route messages between connected nodes. * An object has to supply a template for a class name (only if it can be constructed by the factory) and a template for registering the callable functions (also for abstract base classes which can't be constructed). * A function call is executed asynchronously (wrapper for synchronous call exists). The call to node.call(...) returns a "link_caller"-object. The function to be executed itself can optionally have "link_callee" as the first argument (which is invisible for the caller). The "link_caller"/"link_callee" is used for synchronization (wait for call to begin/finish execution), message forwarding (push/pop strings at caller/callee) and transfer/extraction of the return value. * Objects of class hierarchies with abstract base classes are possible and handled transparently. * Objects can be constructed by the factory of a node or an existing (externally constructed) object can be registered by the node. * Objects don't necessarily need to know (be modified, inherit something etc.) that they are part of the RPC-system and some of their functions are called remotely. * Objects can be aware that they are constructed by the factory and can, on construction be informed about their identity and get a reference to the node to make remote calls themselves. * An object is identified by a "reference" consisting of the "node_id" and the "object_id". * Parameters are passed (serialized, deserialized) by value. All function parameters must have the possibility to be serialized. Modifying referenced parameters won't affect the parameter at the caller. Pointers obviously won't work between nodes not sharing the same memory-address-space. * Called functions can use "link_callee" to make remote calls themselves, regardless of the object. * Priorities are assigned to calls and affect message forwarding and scheduling. * Calls to objects can be transformed into a boost::function using node.bind(...). * If a called function throws, the exception is forwarded as rpc::exception or a more specialized exception class. The exception is thrown at the caller, when waiting for interaction with the callee (e.g. wait for return value). * Template functions as targets are possible when specifying the template parameters of the function pointer when registering the function. * There is no need to use macros at all, although macros could be used to simplify some things. ---------- // Example for creating and calling an object. // Create a service. boost::asio::io_service node_io_service; // Create a node. rpc::node node_s(node_io_service, config); // Register the builder in order to build the server object later. node_s.register_builder<devicelib::chat_server_impl>(); // Register the interface of the client to be able to make calls to it. node_s.register_interface<devicelib::chat_client>(); // Create the server object. rpc::reference cs( node_s.get_id(), node_s.allocate_object_template<devicelib::chat_server_impl>() ); // Store the server in name server. // rpc::reference( node_s.get_id(), rpc::oid_simple_object_name_server ) -> A reference to the object_name_server. // rpc::sched_default() -> Default scheduling parameters. // &rpc::simple_object_name_server::store, cs -> function to call. // cs, "chat_server_object" -> function parameters. node_s.wrap_call( rpc::reference( node_s.get_id(), rpc::oid_simple_object_name_server ), rpc::sched_default(), &rpc::simple_object_name_server::store, cs, "chat_server_object" ); ---------- // Example for abstract base class. namespace devicelib { class chat_server : public chat_types { public: virtual void receive( std::string xml_message ) = 0; virtual user_id_t connect_user( rpc::reference a_client, std::string xml_user_info ) = 0; virtual std::string query_user( user_id_t id ) = 0; virtual void disconnect_user( user_id_t user ) = 0; virtual void join_room( user_id_t user, room_id_t room ) = 0; virtual std::list<user_id_t> list_users( ) = 0; virtual std::list<room_id_t> list_rooms( ) = 0; }; } --------------- // Example for registering the interface of the server object. // The template is declared in namespace rpc, therefore we need to define it there. namespace rpc { // For the base object. template<> void register_proxy_functions<devicelib::chat_server>( function_call_proxy<devicelib::chat_server>& ar_proxy ) { // Register the functions of the abstract base object using unique strings. ar_proxy.register_interface( &devicelib::chat_server::connect_user, "&chat_server::connect_user" ); ar_proxy.register_interface( &devicelib::chat_server::query_user, "&chat_server::query_user" ); ar_proxy.register_interface( &devicelib::chat_server::disconnect_user, "&chat_server::disconnect_user" ); ar_proxy.register_interface( &devicelib::chat_server::join_room, "&chat_server::join_room" ); ar_proxy.register_interface( &devicelib::chat_server::list_users, "&chat_server::list_users" ); ar_proxy.register_interface( &devicelib::chat_server::list_rooms, "&chat_server::list_rooms" ); } // For each implementation. template<> void register_proxy_functions<devicelib::chat_server_impl>( function_call_proxy<devicelib::chat_server_impl>& ar_proxy ) { // Register the functions of the base object. register_proxy_functions<devicelib::chat_server>( (function_call_proxy<devicelib::chat_server>&) ar_proxy ); // Make the functions of this object available. ar_proxy.register_interface( &devicelib::chat_server_impl::connect_user, &devicelib::chat_server::connect_user ); ar_proxy.register_interface( &devicelib::chat_server_impl::disconnect_user, &devicelib::chat_server::disconnect_user ); ar_proxy.register_interface( &devicelib::chat_server_impl::join_room, &devicelib::chat_server::join_room ); ar_proxy.register_interface( &devicelib::chat_server_impl::list_users, &devicelib::chat_server::list_users ); ar_proxy.register_interface( &devicelib::chat_server_impl::list_rooms, &devicelib::chat_server::list_rooms ); } // The implementation can be built, the base object not. template<> std::string class_builder_name<devicelib::chat_server_impl>() { // Give it an unique name here. return "chat_server_impl"; } } ----------------- 1: http://www.boostpro.com/vault/index.php?&direction=0&order=&directory=Distr…

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[program_options] simple test case fails
by Christian Henning 14 Sep '09

14 Sep '09

Hi there, I'm working against the trunk but the following program doesn't run properly. #include <iostream> #include <boost/program_options.hpp> using namespace std; namespace po = boost::program_options; int main(int argc, char* argv[]) { string input; po::options_description desc("Allowed options"); desc.add_options() ( "help,h" , "produce help message" ) ( "input,i" , po::value<string>( &input ), "Input File" ); po::variables_map vm; po::store( po::parse_command_line(argc, argv, desc), vm ); po::notify( vm ); if( vm.count( "help" )) { cout << desc << endl; return 1; } } When calling po::store() I get an assertion saying: "Expression: map/set iterators incompatible". My command line parameter is "--help". I'm using autolink and MSVC 2005. Regards, Christian

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timeconv.inl
by Dan Smithers 11 Sep '09

11 Sep '09

I am porting some inherited code to MSVS 2008 This is also bringing along an upgrade from boost 1.32 to a newer version (probably 1.37). I have found a thread wrapper class in the code that uses time_to directly. This is defined in lib/thread/src/timeconv.inl and doesn't look like its meant to be used directly. The original code base has timeconv.inl in the boost include directory. Was timeconv.inl moved at some point in the past? Is this as bad as I think it is? thanks dan

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