Search Results

Search found 1803 results on 73 pages for 'boost dataflow'.

Page 8/73 | < Previous Page | 4 5 6 7 8 9 10 11 12 13 14 15  | Next Page >

• Using boost::random to select from an std::list where elements are being removed

  - by user144182

  See this related question on more generic use of the Boost Random library. My questions involves selecting a random element from an std::list, doing some operation, which could potentally include removing the element from the list, and then choosing another random element, until some condition is satisfied. The boost code and for loop look roughly like this: // create and insert elements into list std::list<MyClass> myList; //[...] // select uniformly from list indices boost::uniform_int<> indices( 0, myList.size()-1 ); boost::variate_generator< boost::mt19937, boost::uniform_int<> > selectIndex(boost::mt19937(), indices); for( int i = 0; i <= maxOperations; ++i ) { int index = selectIndex(); MyClass & mc = myList.begin() + index; // do operations with mc, potentially removing it from myList //[...] } My problem is as soon as the operations that are performed on an element result in the removal of an element, the variate_generator has the potential to select an invalid index in the list. I don't think it makes sense to completely recreate the variate_generator each time, especially if I seed it with time(0).

  Read the article

• How to create a array of boost matrices?

  - by Venkata Adusumilli

  How can I define a array of boost matrices as a member variable? None of the following worked. boost::numeric::ublas::matrix arrayM(1, 3)[arraySize]; boost::numeric::ublas::matrix(1, 3) arrayM[arraySize]; boost::numeric::ublas::matrix arrayM[arraySize](1, 3); Thanks, Ravi.

  Read the article

• Boost and XML (c++)

  - by Nuno

  Hi, Is there any good way (and a simple way too) using boost to read and write xml files? I can't seem to find any simple sample to read xml files using boost? (can you point me some simple sample that use boost for reading and writing xml files) If not boost, is out there any good and simple library to read and write xml files that you can recommend? (it must be a c++ library) Thanks Nuno

  Read the article

• How Important is Boost to Learn for C++ Developers

  - by mahesh

  I am curious to learn Boost. But i wanted to ask how important it is to learn. What pre-requisite one should need before jumping on Boost. Why i am curious to know about Boost is that many people are talking about Boost on IRC's channels and here in StackOverflow. Thanks in advance.

  Read the article

• How to remove compiler flag when building Boost

  - by mlo

  I need to build Boost with a non-standard set of flags (due to a conflict between Boost threading and C++/CLI). I'm adding the required flag (/clr) using CXXFLAGS, but this flag conflicts with the Boost default /EHs flag (/clr implies /EHa which is incompatible with /EHs), so that needs to be suppressed. Is there a mechanism like CXXFLAGS to suppress a default Boost flag or must I edit all of the compiler specification files by hand?

  Read the article

• Signals and threads - good or bad design decision?

  - by Jens

  I have to write a program that performs highly computationally intensive calculations. The program might run for several days. The calculation can be separated easily in different threads without the need of shared data. I want a GUI or a web service that informs me of the current status. My current design uses BOOST::signals2 and BOOST::thread. It compiles and so far works as expected. If a thread finished one iteration and new data is available it calls a signal which is connected to a slot in the GUI class. My question(s): Is this combination of signals and threads a wise idea? I another forum somebody advised someone else not to "go down this road". Are there potential deadly pitfalls nearby that I failed to see? Is my expectation realistic that it will be "easy" to use my GUI class to provide a web interface or a QT, a VTK or a whatever window? Is there a more clever alternative (like other boost libs) that I overlooked? following code compiles with g++ -Wall -o main -lboost_thread-mt <filename>.cpp code follows: #include <boost/signals2.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <iostream> #include <iterator> #include <string> using std::cout; using std::cerr; using std::string; /** * Called when a CalcThread finished a new bunch of data. */ boost::signals2::signal<void(string)> signal_new_data; /** * The whole data will be stored here. */ class DataCollector { typedef boost::mutex::scoped_lock scoped_lock; boost::mutex mutex; public: /** * Called by CalcThreads call the to store their data. */ void push(const string &s, const string &caller_name) { scoped_lock lock(mutex); _data.push_back(s); signal_new_data(caller_name); } /** * Output everything collected so far to std::out. */ void out() { typedef std::vector<string>::const_iterator iter; for (iter i = _data.begin(); i != _data.end(); ++i) cout << " " << *i << "\n"; } private: std::vector<string> _data; }; /** * Several of those can calculate stuff. * No data sharing needed. */ struct CalcThread { CalcThread(string name, DataCollector &datcol) : _name(name), _datcol(datcol) { } /** * Expensive algorithms will be implemented here. * @param num_results how many data sets are to be calculated by this thread. */ void operator()(int num_results) { for (int i = 1; i <= num_results; ++i) { std::stringstream s; s << "["; if (i == num_results) s << "LAST "; s << "DATA " << i << " from thread " << _name << "]"; _datcol.push(s.str(), _name); } } private: string _name; DataCollector &_datcol; }; /** * Maybe some VTK or QT or both will be used someday. */ class GuiClass { public: GuiClass(DataCollector &datcol) : _datcol(datcol) { } /** * If the GUI wants to present or at least count the data collected so far. * @param caller_name is the name of the thread whose data is new. */ void slot_data_changed(string caller_name) const { cout << "GuiClass knows: new data from " << caller_name << std::endl; } private: DataCollector & _datcol; }; int main() { DataCollector datcol; GuiClass mc(datcol); signal_new_data.connect(boost::bind(&GuiClass::slot_data_changed, &mc, _1)); CalcThread r1("A", datcol), r2("B", datcol), r3("C", datcol), r4("D", datcol), r5("E", datcol); boost::thread t1(r1, 3); boost::thread t2(r2, 1); boost::thread t3(r3, 2); boost::thread t4(r4, 2); boost::thread t5(r5, 3); t1.join(); t2.join(); t3.join(); t4.join(); t5.join(); datcol.out(); cout << "\nDone" << std::endl; return 0; }

  Read the article

• How can I build the Boost.Python example on Ubuntu 9.10?

  - by Gatlin

  I am using Ubuntu 9.10 beta, whose repositories contain boost 1.38. I would like to build the hello-world example. I followed the instructions here (http://www.boost.org/doc/libs/1%5F40%5F0/libs/python/doc/tutorial/doc/html/python/hello.html), found the example project, and issued the "bjam" command. I have installed bjam and boost-build. I get the following output: Jamroot:18: in modules.load rule python-extension unknown in module Jamfile</usr/share/doc/libboost1.38-doc/examples/libs/python/example>. /usr/share/boost-build/build/project.jam:312: in load-jamfile /usr/share/boost-build/build/project.jam:68: in load /usr/share/boost-build/build/project.jam:170: in project.find /usr/share/boost-build/build-system.jam:248: in load /usr/share/boost-build/kernel/modules.jam:261: in import /usr/share/boost-build/kernel/bootstrap.jam:132: in boost-build /usr/share/doc/libboost1.38-doc/examples/libs/python/example/boost-build.jam:7: in module scope I do not know enough about Boost (this is an exploratory exercise for myself) to understand why the python-extension macro in the included Jamroot is not valid. I am running this example from the install directory, so I have not altered the Jamroot's use-project setting. As a side question, if I were to just willy-nilly start a project in an arbitrary directory, how would I write my jamroot?

  Read the article

• Solving a difficult incomplete type error

  - by ChAoS

  I get an incomplete type error when trying to compile my code. I know that it is related to includes, but my project is large and it uses several templates so I can't find which type is actually incomplete. The error message doesn't help either: Compiling: ../../../addons/ofxTableGestures/src/Graphics/objects/CursorFeedback.cpp In file included from ../../../addons/ofxTableGestures/ext/boost/fusion/include/invoke_procedure.hpp:10, from ../../../addons/ofxTableGestures/src/oscGestures/tuioApp.hpp:46, from /home/thechaos/Projectes/of_preRelease_v0061_linux_FAT/addons/../apps/OF-TangibleFramework/ofxTableGestures/src/Graphics/objects/CursorFeedback.hpp:35, from /home/thechaos/Projectes/of_preRelease_v0061_linux_FAT/addons/../apps/OF-TangibleFramework/ofxTableGestures/src/Graphics/objects/CursorFeedback.cpp:31: ../../../addons/ofxTableGestures/ext/boost/fusion/functional/invocation/invoke_procedure.hpp: In function ‘void boost::fusion::invoke_procedure(Function, const Sequence&) [with Function = void (tuio::CanBasicFingers<Graphic>::*)(long int, float, float, float, float, float), Sequence = boost::fusion::joint_view<boost::fusion::joint_view<boost::fusion::iterator_range<boost::fusion::vector_iterator<const boost::fusion::vector6<long int, float, float, float, float, float>, 0>, boost::fusion::vector_iterator<boost::fusion::vector6<long int, float, float, float, float, float>, 0> >, const boost::fusion::single_view<tuio::CanBasicFingers<Graphic>*> >, boost::fusion::iterator_range<boost::fusion::vector_iterator<boost::fusion::vector6<long int, float, float, float, float, float>, 0>, boost::fusion::vector_iterator<const boost::fusion::vector6<long int, float, float, float, float, float>, 6> > >]’: ../../../addons/ofxTableGestures/src/oscGestures/tuioApp.hpp:122: instantiated from ‘void tuio::AlternateCallback<C, M, E>::run(tuio::TEvent*) [with C = tuio::CanBasicFingers<Graphic>, M = void (tuio::CanBasicFingers<Graphic>::*)(long int, float, float, float, float, float), E = tuio::TeventBasicFingersMoveFinger]’ /home/thechaos/Projectes/of_preRelease_v0061_linux_FAT/addons/../apps/OF-TangibleFramework/ofxTableGestures/src/Graphics/objects/CursorFeedback.cpp:64: instantiated from here ../../../addons/ofxTableGestures/ext/boost/fusion/functional/invocation/invoke_procedure.hpp:88: error: incomplete type ‘boost::fusion::detail::invoke_procedure_impl<void (tuio::CanBasicFingers<Graphic>::*)(long int, float, float, float, float, float), const boost::fusion::joint_view<boost::fusion::joint_view<boost::fusion::iterator_range<boost::fusion::vector_iterator<const boost::fusion::vector6<long int, float, float, float, float, float>, 0>, boost::fusion::vector_iterator<boost::fusion::vector6<long int, float, float, float, float, float>, 0> >, const boost::fusion::single_view<tuio::CanBasicFingers<Graphic>*> >, boost::fusion::iterator_range<boost::fusion::vector_iterator<boost::fusion::vector6<long int, float, float, float, float, float>, 0>, boost::fusion::vector_iterator<const boost::fusion::vector6<long int, float, float, float, float, float>, 6> > >, 7, true, false>’ used in nested name specifier If I copy the conflictive code to a same file I can compile it. So I know that the code itself is OK, the problem is the way I instantiate it. How can I trace the origin of this error? Is there any way to get the trace of the c++ compiler and preprocessor to get more informative messages?

  Read the article

• async_write/async_read problems while trying to implement question-answer logic

  - by Max

  Good day. I'm trying to implement a question - answer logic using boost::asio. On the Client I have: void Send_Message() { .... boost::asio::async_write(server_socket, boost::asio::buffer(&Message, sizeof(Message)), boost::bind(&Client::Handle_Write_Message, this, boost::asio::placeholders::error)); .... } void Handle_Write_Message(const boost::system::error_code& error) { .... std::cout << "Message was sent.\n"; .... boost::asio::async_read(server_socket_,boost::asio::buffer(&Message, sizeof(Message)), boost::bind(&Client::Handle_Read_Message, this, boost::asio::placeholders::error)); .... } void Handle_Read_Message(const boost::system::error_code& error) { .... std::cout << "I have a new message.\n"; .... } And on the Server i have the "same - logic" code: void Read_Message() { .... boost::asio::async_read(client_socket, boost::asio::buffer(&Message, sizeof(Message)), boost::bind(&Server::Handle_Read_Message, this, boost::asio::placeholders::error)); .... } void Handle_Read_Message(const boost::system::error_code& error) { .... std::cout << "I have a new message.\n"; .... boost::asio::async_write(client_socket_,boost::asio::buffer(&Message, sizeof(Message)), boost::bind(&Server::Handle_Write_Message, this, boost::asio::placeholders::error)); .... } void Handle_Write_Message(const boost::system::error_code& error) { .... std::cout << "Message was sent back.\n"; .... } Message it's just a structure. And the output on the Client is: Message was sent. Output on the Server is: I have a new message. And that's all. After this both programs are still working but nothing happens. I tried to implement code like: if (!error) { .... } else { // close sockets and etc. } But there are no errors in reading or writing. Both programs are just running normally, but doesn't interact with each other. This code is quite obvious but i can't understand why it's not working. Thanks in advance for any advice.

  Read the article

• g++ linker error--typeinfo, but not vtable

  - by James

  I know the standard answer for a linker error about missing typeinfo usually also involves vtable and some virtual function that I forgot to actually define. I'm fairly certain that's not the situation this time. Here's the error: UI.o: In function boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::Resource::GroupByState>(boost::shared_ptr<Graphics::Resource::GroupByState> const&, boost::detail::dynamic_cast_tag)': UI.cpp:(.text._ZN5boost10shared_ptrIN8Graphics7Widgets9WidgetSetEEC1INS1_8Resource12GroupByStateEEERKNS0_IT_EENS_6detail16dynamic_cast_tagE[boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::Resource::GroupByState>(boost::shared_ptr<Graphics::Resource::GroupByState> const&, boost::detail::dynamic_cast_tag)]+0x30): undefined reference totypeinfo for Graphics::Widgets::WidgetSet' Running c++filt on the obnoxious mangled name shows that it actually is looking at .boost::shared_ptr::shared_ptr(boost::shared_ptr const&, boost::detail::dynamic_cast_tag) The inheritance hierarchy looks something like class AbstractGroup { typedef boost::shared_ptr<AbstractGroup> Ptr; ... }; class WidgetSet : public AbstractGroup { typedef boost::shared_ptr<WidgetSet> Ptr; ... }; class GroupByState : public AbstractGroup { ... }; Then there's this: class UI : public GroupByState { ... void LoadWidgets( GroupByState::Ptr resource ); }; Then the original implementation: void UI::LoadWidgets( GroupByState::Ptr resource ) { WidgetSet::Ptr tmp( boost::dynamic_pointer_cast< WidgetSet >(resource) ); if( tmp ) { ... } } Stupid error on my part (trying to cast to a sibling class with a shared parent), even if the error is kind of cryptic. Changing to this: void UI::LoadWidgets( AbstractGroup::Ptr resource ) { WidgetSet::Ptr tmp( boost::dynamic_pointer_cast< WidgetSet >(resource) ); if( tmp ) { ... } } (which I'm fairly sure is what I actually meant to be doing) left me with a very similar error: UI.o: In function boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::_Drawer::Group>(boost::shared_ptr<Graphics::_Drawer::Group> const&, boost::detail::dynamic_cast_tag)': UI.cpp:(.text._ZN5boost10shared_ptrIN8Graphics7Widgets9WidgetSetEEC1INS1_7_Drawer5GroupEEERKNS0_IT_EENS_6detail16dynamic_cast_tagE[boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::_Drawer::Group>(boost::shared_ptr<Graphics::_Drawer::Group> const&, boost::detail::dynamic_cast_tag)]+0x30): undefined reference totypeinfo for Graphics::Widgets::WidgetSet' collect2: ld returned 1 exit status dynamic_cast_tag is just an empty struct in boost/shared_ptr.hpp. It's just a guess that boost might have anything at all to do with the error. Passing in a WidgetSet::Ptr totally eliminates the need for a cast, and it builds fine (which is why I think there's more going on than the standard answer for this question). Obviously, I'm trimming away a lot of details that might be important. My next step is to cut it down to the smallest example that fails to build, but I figured I'd try the lazy way out and take a stab on here first. TIA!

  Read the article

• What is wrong with this attempt of sending a break-signal?

  - by Jook

  I have quite a headache about this seemingly easy task: send a break signal to my device, like the wxTerm (or any similar Terminal application) does. This signal has to be 125ms long, according to my tests and the devices specification. It should result in a specific response, but what I get is a longer response than expected, and the transmitted date is false. e.g.: what it should respond 08 00 81 00 00 01 07 00 what it does respond 08 01 0A 0C 10 40 40 07 00 7F What really boggles me is, that after I have used wxTerm to look at my available com-ports (without connecting or sending anything), my code starts to work! I can send then as many breaks as I like, I get my response right from then on. I have to reset my PC in order to try it again. What the heck is going on here?! Here is my code for a reset through a break-signal: minicom_client(boost::asio::io_service& io_service, unsigned int baud, const string& device) : active_(true), io_service_(io_service), serialPort(io_service, device) { if (!serialPort.is_open()) { cerr << "Failed to open serial port\n"; return; } boost::asio::serial_port_base::flow_control FLOW( boost::asio::serial_port_base::flow_control::hardware ); boost::asio::serial_port_base::baud_rate baud_option(baud); serialPort.set_option(FLOW); serialPort.set_option(baud_option); read_start(); std::cout << SetCommBreak(serialPort.native_handle()) << std::endl; std::cout << GetLastError() << std::endl; boost::posix_time::ptime mst1 = boost::posix_time::microsec_clock::local_time(); boost::this_thread::sleep(boost::posix_time::millisec(125)); boost::posix_time::ptime mst2 = boost::posix_time::microsec_clock::local_time(); std::cout << ClearCommBreak(serialPort.native_handle()) << std::endl; std::cout << GetLastError() << std::endl; boost::posix_time::time_duration msdiff = mst2 - mst1; std::cout << msdiff.total_milliseconds() << std::endl; } Edit: It was only necessary to look at the combo-box selection of com-ports of wxTerm - no active connection was needed to be established in order to make my code work. I am guessing, that there is some sort of initialisation missing, which is done, when wxTerm is creating the list for the serial-port combo-box.

  Read the article

• Boost.python building

  - by Ockonal

  Hi guys, really can't understand, how to build correctly project that uses boost.python. I've included boost_(python/thread/system)-mt. Here is simple module file: #include <boost/python.hpp> #include "script.hpp" #include "boost/python/detail/wrap_python.hpp" BOOST_PYTHON_MODULE(temp) { namespace py = boost::python; py::def("PyLog", &engine::log); } Here is bulid log: http://dpaste.com/179232/. Can't imagine what I forgot. System: arch linux; ls /usr/lib |grep boost : http://dpaste.com/179233/

  Read the article

• Zlib compression in boost::iostreams not compatible with zlib.NET

  - by Johan

  Hello, I want to send compressed data between my C# to a C++ application in ZLIB format. In C++, I use the zlib_compressor/zlib_decompressor available in boost::iostreams. In C#, I am currently using the ZOutputStream available in the zlib.NET library. First of all, when I compress the same data using both libraries, the results look different: boost::iostreams::zlib_compressor: FF 13 49 48 00 00 01 00 01 00 00 00 63 61 60 60 F8 00 C4 C1 25 45 99 79 E9 23 87 04 00 zlib.NET (zlib.ZOutputStream): FF 13 49 48 00 00 01 00 01 00 00 00 78 9C 63 61 60 60 F8 00 C4 C1 25 45 99 79 E9 23 87 04 00 4F 31 63 8D (Note the 78 9C pattern that is present in zlib.NET, but not in boost). Furthermore, when I decompress data in boost that I compressed in zlib.NET, I am not able to read from the stream suggesting something is wrong. It does work when I try to decompress data compressed in boost. Does anybody know what is going wrong? Thank you, Johan

  Read the article

• Using boost::iostreams to parse a binary file byte by byte

  - by Zsol

  So I would like to parse a binary file and extract some data from it. The problem I am facing with this is that I need to convert a stream of chars to a stream of unsigned chars. Reading the boost documentation, it seems that boost::iostreams::code_converter should be the solution for this, so I tried this: typedef unsigned char uint8_t; typedef boost::iostreams::stream<boost::iostreams::code_converter< boost::iostreams::basic_array_source<uint8_t> >, std::codecvt<uint8_t, char, std::mbstate_t> > array_stream; The idea was to specify a codecvt with InternalType=uint8_t and ExternalType=char. Unfortunately this does not compile. So the question is: how do I convert a stream of chars to a stream of uint8_ts?

  Read the article

• Building Boost with LSB C++ Compiler

  - by Alex Farber

  I want to build my program with LSB C++ Compiler from the Linux Standard Base http://www.linuxfoundation.org/collaborate/workgroups/lsb. Program depends on the Boost library, built with gcc 4.4 version. Compilation fails. Is it possible to build the Boost library with LSB C++ Compiler? Alternatively, is it possible to build the Boost library with some old gcc version, what version is recommended? My final goal is to get my executable and third-party Boost libraries running on most Linux distributions. Generally, what can be done to get better binary compatibility for Linux distributions, developing C++ closed-source application depending on the Boost library?

  Read the article

• Python extension building with boost

  - by user1544053

  Hey guys I'm fairly new to boost c/c++ library. I downloaded boost library and build the library. I created a very simple python library in c++ using boost interface (actually it is example code given in the documentation). I built it into a dll file. In the documentation it reads that this dll is exposed to python and they just show the import function in python and include the created library. I don't understand how to expose that dll to python and load the library inside in tradition ('import') manner. In case if you wanna look at the code then here it is: #include <boost/python.hpp> char const* greet() { return "hello, world"; } BOOST_PYTHON_MODULE(hello_ext) { using namespace boost::python; def("greet", greet); } Please help I really want to build applications with c/c++ and python. I simply want to use hello_ext as: >>>import hello_ext >>>print hello_ext.greet() Thank you.

  Read the article

• boost::this_thread::disable_interruption usage confusion

  - by Evgenii

  boost/thread/pthread/shared_mutex.hpp contains this code: ... #include <boost/thread/detail/thread_interruption.hpp> ... class shared_mutex { ... void lock_shared() { boost::this_thread::disable_interruption do_not_disturb; boost::mutex::scoped_lock lk(state_change); while(state.exclusive || state.exclusive_waiting_blocked) { shared_cond.wait(lk); } ++state.shared_count; } ... }; but boost/thread/detail/thread_interruption.hpp does not contain implementation of disable_interruption, only the prototype. in boost_1_42_0/libs/thread/src/pthread we don't have the implementation too how does it work!???

  Read the article

• Boost ASIO read X bytes synchroniously into a vector

  - by xeross

  Hey, I've been attempting to write a client/server app with boost now, so far it sends and receives but I can't seem to just read X bytes into a vector. If I use the following code vector<uint8_t> buf; for (;;) { buf.resize(4); boost::system::error_code error; size_t len = socket.read_some(boost::asio::buffer(buf), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. } And the packet is bigger then 4 bytes then it seems it keeps writing into those 4 bytes until the entire packet has been received, however I want it to fetch 4 bytes, then allow me to parse them, and then get the rest of the packet. Can anyone provide me with a working example, or at least a pointer on how to make it work properly ? Regards, Xeross

  Read the article

• How do I get the size of the boost buffer

  - by Anonymous

  I am trying to make an asynchronised server in visual studio and I use boost::asio::async_read(m_socket, boost::asio::buffer(m_buffer), boost::bind(&tcp_connection::handle_read, shared_from_this(), boost::asio::placeholders::error)); to get the buffer to be put in m_buffer boost::array<char, 256> m_buffer; but how do I get the size of this thing, m_buffer? size() didn't work, end() didn't work.. Any help would be fantastic. Thanks in advance.

  Read the article

• how to use replace_regex_copy() from boost::algorithm library?

  - by Vincenzo

  This is my code: #include <string> #include <boost/algorithm/string/regex.hpp> string f(const string& s) { using namespace boost::algorithm; return replace_regex_copy(s, "\\w", "?"); } This is what compiler says: no matching function for call to ‘replace_regex_copy(const std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::string, std::string) The link to the library: http://www.boost.org/doc/libs/1_43_0/doc/html/boost/algorithm/replace_regex_copy.html Could anyone please help? Thanks! ps. Boost library is in place, since other functions from it work fine.

  Read the article

• Using * Width & Precision Specifiers With boost::format

  - by John Dibling

  I am trying to use width and precision specifiers with boost::format, like this: #include <boost\format.hpp> #include <string> int main() { int n = 5; std::string s = (boost::format("%*.*s") % (n*2) % (n*2) % "Hello").str(); return 0; } But this doesn't work because boost::format doesn't support the * specifier. Boost throws an exception when parsing the string. Is there a way to accomplish the same goal, preferably using a drop-in replacement?

  Read the article

• What is a good motivating example for dataflow concurrency?

  - by Alex Miller

  I understand the basics of dataflow programming and have encountered it a bit in Clojure APIs, talks from Jonas Boner, GPars in Groovy, etc. I know it's prevalent in languages like Io (although I have not studied Io). What I am missing is a compelling reason to care about dataflow as a paradigm when building a concurrent program. Why would I use a dataflow model instead of a mutable state+threads+locks model (common in Java, C++, etc) or an actor model (common in Erlang or Scala) or something else? In particular, while I know of library support in the languages above (and Scala and Ruby), I don't know of a single program or library that is a poster child user of this model. Who is using it? Why do they find it better than the other models I mentioned?

  Read the article

• boost::filesystem - how to create a boost path from a windows path string on posix plattforms?

  - by VolkA

  I'm reading path names from a database which are stored as relative paths in Windows format, and try to create a boost::filesystem::path from them on a Unix system. What happens is that the constructor call interprets the whole string as the filename. I need the path to be converted to a correct Posix path as it will be used locally. I didn't find any conversion functions in the boost::filesystem reference, nor through google. Am I just blind, is there an obvious solution? If not, how would you do this? Example: std::string win_path("foo\\bar\\asdf.xml"); std::string posix_path("foo/bar/asdf.xml"); // loops just once, as part is the whole win_path interpreted as a filename boost::filesystem::path boost_path(win_path); BOOST_FOREACH(boost::filesystem::path part, boost_path) { std::cout << part << std::endl; } // prints each path component separately boost::filesystem::path boost_path_posix(posix_path); BOOST_FOREACH(boost::filesystem::path part, boost_path_posix) { std::cout << part << std::endl; }

  Read the article

• wrapping boost::ublas with swig

  - by leon

  I am trying to pass data around the numpy and boost::ublas layers. I have written an ultra thin wrapper because swig cannot parse ublas' header correctly. The code is shown below #include <boost/numeric/ublas/vector.hpp> #include <boost/numeric/ublas/matrix.hpp> #include <boost/lexical_cast.hpp> #include <algorithm> #include <sstream> #include <string> using std::copy; using namespace boost; typedef boost::numeric::ublas::matrix<double> dm; typedef boost::numeric::ublas::vector<double> dv; class dvector : public dv{ public: dvector(const int rhs):dv(rhs){;}; dvector(); dvector(const int size, double* ptr):dv(size){ copy(ptr, ptr+sizeof(double)*size, &(dv::data()[0])); } ~dvector(){} }; with the SWIG interface that looks something like %apply(int DIM1, double* INPLACE_ARRAY1) {(const int size, double* ptr)} class dvector{ public: dvector(const int rhs); dvector(); dvector(const int size, double* ptr); %newobject toString; char* toString(); ~dvector(); }; I have compiled them successfully via gcc 4.3 and vc++9.0. However when I simply run a = dvector(array([1.,2.,3.])) it gives me a segfault. This is the first time I use swigh with numpy and not have fully understanding between the data conversion and memory buffer passing. Does anyone see something obvious I have missed? I have tried to trace through with a debugger but it crashed within the assmeblys of python.exe. I have no clue if this is a swig problem or of my simple wrapper. Anything is appreciated.

  Read the article

• Boost thread synchronization in release build

  - by Joseph16

  Hi, when I try to run the following code in debug and release mode in VS2005. Each time I see different output in console and It doesn't seem like the multithreading is achieved in release mode. 1. #include <boost/thread.hpp> 2. #include <iostream> 3. 4. void wait(int seconds) 5. { 6. boost::this_thread::sleep(boost::posix_time::seconds(seconds)); 7. } 8. 9. boost::mutex mutex; 10. 11. void thread() 12. { 13. for (int i = 0; i < 5; ++i) 14. { 15. //wait(1); 16. mutex.lock(); 17. std::cout << "Thread " << boost::this_thread::get_id() << ": " << i << std::endl; 18. mutex.unlock(); 19. } 20. } 21. 22. int main() 23. { 24. boost::thread t1(thread); 25. boost::thread t2(thread); 26. t1.join(); 27. t2.join(); 28. } Debug Mode Thread 00153E60: 0 Thread 00153E90: 0 Thread 00153E60: 1 Thread 00153E90: 1 Thread 00153E90: 2 Thread 00153E60: 2 Thread 00153E90: 3 Thread 00153E60: 3 Thread 00153E60: 4 Thread 00153E90: 4 Press any key to continue . . . Release Mode Thread 00153D28: 0 Thread 00153D28: 1 Thread 00153D28: 2 Thread 00153D28: 3 Thread 00153D28: 4 Thread 00153D58: 0 Thread 00153D58: 1 Thread 00153D58: 2 Thread 00153D58: 3 Thread 00153D58: 4 Press any key to continue . . .

  Read the article

< Previous Page | 4 5 6 7 8 9 10 11 12 13 14 15  | Next Page >