October 2009 - Boost-users - lists.boost.org

[boost] Create Graph in Function
by James Thunes 29 Oct '09

29 Oct '09

Perhaps an easy answer, but I am working on adding a boost graph to an existing code. I would like to create the graph in a function (not main) and then read/modify it in a separate function. I am unsure as to what I need to pass between the functions to allow this to work. In other words, I am able to correctly create the graph in a function and modify as necessary. This function will be called many times as the code runs and it is inefficient to recreate the graph every time. I want to create the graph once when the code is run and pass the created graph to the function. Due to the structure of the code (mostly Fortran), I can not define the graph in the main function of the code. My graph is defined as: adjacency_list<vecS, vecS, bidirectionalS, no_property, EdgeProperty> Graph; Thank you for any help you can give, James

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Multiple binds on a asio socket
by Lee MacDonald 29 Oct '09

29 Oct '09

Hi, Is it possible to have multiple binds on a single socket instance? Say I have two multicast addresses that share the same port and use the same nic. On linux I would bind like so: listenEndPoint1(multicastAddress1.to_v4(), port); socket_.bind(listenEndPoint1); socket_.set_option(asio::ip::multicast::join_group(multicastAddress1.to_ v4(), interfaceAddress.to_v4())); } Can I then perform a second bind and join for the other multicast address? listenEndPoint2(multicastAddress2.to_v4(), port); socket_.bind(listenEndPoint2); socket_.set_option(asio::ip::multicast::join_group(multicastAddress2.to_ v4(), interfaceAddress.to_v4())); } If this is not possible or good practice, what would be the alternative? Regards, Lee MacDonald Schneider Trading 4th Floor, 25 Copthall Avenue London EC2R 7BP ________________________________ Message from: lee.macdonald(a)schneidertrading.com Message to: asio-users(a)lists.sourceforge.net Attached files: 0 This e-mail and any files transmitted with it are confidential, may be legally privileged, and are for the sole use of the intended recipient. Copyright in this e-mail and any accompanying document created by us is owned by us. If you are not the intended recipient of this e-mail or any part of it please telephone our IT Department at the number shown above or by e-mail at info(a)schneidertrading.com. You should not use or disclose to any other person the contents of this e-mail or its attachments (if any), nor take copies. This e-mail is not a representation or warranty and is not intended nor should it be taken to create any legal relations, contractual or otherwise. Schneider Trading Associates Ltd (Registration No. 3692131) is incorporated in England and Wales and the registered office is at 25 Copthall Avenue, London EC2R 7BP. The company is authorised and regulated by the Financial Services Authority Schneider Trading 4th Floor, 25 Copthall Avenue London EC2R 7BP -------------------------------------------------------- Message from: lee.macdonald(a)schneidertrading.com Message to: boost-users(a)lists.boost.org Attached files: 0 This e-mail and any files transmitted with it are confidential, may be legally privileged, and are for the sole use of the intended recipient. Copyright in this e-mail and any accompanying document created by us is owned by us. If you are not the intended recipient of this e-mail or any part of it please telephone our IT Department at the number shown above or by e-mail at info(a)schneidertrading.com. You should not use or disclose to any other person the contents of this e-mail or its attachments (if any), nor take copies. This e-mail is not a representation or warranty and is not intended nor should it be taken to create any legal relations, contractual or otherwise. Schneider Trading Associates Ltd (Registration No. 3692131) is incorporated in England and Wales and the registered office is at 25 Copthall Avenue, London EC2R 7BP. The company is authorised and regulated by the Financial Services Authority

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Re: [Boost-users] Signal handler for Unix platforms
by Boris Schaeling 29 Oct '09

29 Oct '09

On Wed, 28 Oct 2009 23:18:04 +0100, Rutger ter Borg <rutger(a)terborg.net> wrote: Hi Rutger, > [...]have a couple of questions. Currently a part of the semantics is > > sh.add_signal( SIGUSR1 ); > sh.async_wait( handler ); > > Wouldn't it be easier to be able to write > > sh.async_wait( SIGUSR1, handler ); this would work if you wait for only one signal unless ... > Alternatively, if catching multiple signals by one handler is required, > one > could think of something like > > sh.async_wait( sigusr1 | sigterm | sigabrt, handler ); ... this notion is supported. But this would require to redefine every signal (like sigusr1 for SIGUSR1)? Is this practically possible? I wonder how many differences there are between platforms and if this causes more maintenance effort? I also wonder what is more asio-like. If I look at the I/O objects of Boost.Asio it seems like they are always configured before an asynchronous operation is called. For example when using the deadline_timer expires_at() or expires_from_now() must be called before async_wait() is called. > sh.async_wait( boost::asio::posix::any_signal, handler ); Same answer as above. :) Apart from that I wonder how many developers would benefit from boost::asio::posix::any_signal. Are there so many applications which need to wait for all signals? > Does the signal ID belong in the signature of the handler function? Am I Yes, please see the test cases test/sync.cpp and test/async.cpp. Here's a simple example: ---------- #include "signal_handler.hpp" #include <boost/asio.hpp> #include <signal.h> void signal_handler(const boost::system::error_code &ec, int signal) { } int main() { boost::asio::io_service io_service; boost::asio::posix::signal_handler sh(io_service); sh.add_signal(SIGUSR1); sh.async_wait(signal_handler); io_service.run(); } ---------- > correct that support for real-time signals is missing at the moment? Not sure as I never used real-time signals. :) Looking up real-time signals the difference is merely prioritized delivery times and signal queues? If that's all real-time signals should be supported. The signal handler puts signals into a std::deque<int> object and doesn't merge signals either (when you call wait() or async_wait() the next signal is fetched from the queue). Boris

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[ANN] CLI command line interface compiler for C++
by Boris Kolpackov 29 Oct '09

29 Oct '09

Hi, I am pleased to announce the first public release of CLI. CLI is an open-source (MIT license), cross-platform command line interface compiler for C++. It allows you to specify the options that your program supports, their types, and default values. For example: include <string>; class options { bool --help; std::string --name = "example"; unsigned int --level | -l = 5; }; This specification can then be automatically translated to C++ classes that implement parsing of the command line arguments and provide a convenient and type-safe interface for accessing the extracted data. For example: #include <string> class options { public: options (int argc, char** argv); options (int argc, char** argv, int& end); bool help () const; const std::string& name () const; unsigned int level () const; ... }; int main (int argc, char* argv[]) { options o (argc, argv); if (o.help ()) print_usage (); if (o.level () > 4) cerr << "name is " << o.name () << endl; ... } It is easy to start using CLI in your application since there are no external dependencies. You can compile your command line interface to C++ and simply add the generated files to your project's source code. For a five minute introduction to CLI, see the "Hello World" example in the CLI Getting Started Guide: http://www.codesynthesis.com/projects/cli/doc/guide/#2 More information, documentation, and source code distributions are available from the project's web page: http://www.codesynthesis.com/projects/cli/ Enjoy, Boris -- Boris Kolpackov, Code Synthesis Tools http://codesynthesis.com/~boris/blog Open-source XML data binding for C++: http://codesynthesis.com/products/xsd XML data binding for embedded systems: http://codesynthesis.com/products/xsde

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[serialization] Serializing a reference
by Ben 29 Oct '09

29 Oct '09

Hello Boost Experts -- And now for my real question. Again, g++ 4.2.1, OS X 10.6.1, boost 1.40. I'm trying to follow the instructions in the document for serializing classes with reference members, which suggests I serialize them as pointers. First, a program which works, that uses pointers and not references: #include <iostream> #include <fstream> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> struct A { int v; template<class Ar> void serialize(Ar & ar, const unsigned int ver) { ar & v; } }; struct B { A *ap; B(A *ap_) : ap(ap_) {} template<class Ar> void serialize(Ar & ar, const unsigned int ver) {} }; template<class Ar> void save_construct_data(Ar & ar, const B * b, const unsigned int ver) { ar << b->ap; } template<class Ar> void load_construct_data(Ar & ar, B * b, const unsigned int ver) { A * ap_; ar >> ap_; ::new(b)B(ap_); } int main(int ac, char ** argv) { A a; a.v = 10; B * b1p; b1p = new B(&a); const char * fname = "test.bin"; { std::ofstream ofs(fname); boost::archive::binary_oarchive ar(ofs); ar << b1p; } B * b2p; { std::ifstream ifs(fname); boost::archive::binary_iarchive ar(ifs); ar >> b2p; } std::cout << b2p->ap->v << std::endl; return 0; } What I would really like to do is to modify this program so that class B has a reference to class A instead of a pointer. The documentation suggests I do the following: "This raises the question of how and where the objects being referred to are stored and how are they created. Also there is the question about references to polymorphic base classes. Basically, these are the same questions that arise regarding pointers. This is no surprise as references are really a special kind of pointer. We address these questions by serializing references as though they were pointers." The example given after this serializes the address of the referenced object, similar to the above. My translation of that code is: #include <iostream> #include <fstream> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> struct A { int v; template<class Ar> void serialize(Ar & ar, const unsigned int ver) { ar & v; } }; struct B { A &a; B(A &a_) : a(a_) {} template<class Ar> void serialize(Ar & ar, const unsigned int ver) {} }; template<class Ar> void save_construct_data(Ar & ar, const B * b, const unsigned int ver) { ar << (&(b->a)); } template<class Ar> void load_construct_data(Ar & ar, B * b, const unsigned int ver) { A * ap_; ar >> ap_; ::new(b)B(*ap_); } int main(int ac, char ** argv) { A a; a.v = 10; B * b1p; b1p = new B(a); const char * fname = "test.bin"; { std::ofstream ofs(fname); boost::archive::binary_oarchive ar(ofs); ar << b1p; } B * b2p; { std::ifstream ifs(fname); boost::archive::binary_iarchive ar(ifs); ar >> b2p; } std::cout << b2p->a.v << std::endl; return 0; } This however fails to compile, with the message: Compilation started at Fri Oct 23 15:25:29 make -k debug make all "CXX_FLAGS = -g -fno-inline -m64 -I. -I.. -I/opt/local/include -Wall -Wextra -Wpointer-arith -Wcast-align -Wwrite-strings -Wconversion -Woverloaded-virtual -Wno-sign-compare -Wno-unused -fno-nonansi-builtins" \ "LD_FLAGS = -g -m64" g++ -g -fno-inline -m64 -I. -I.. -I/opt/local/include -Wall -Wextra -Wpointer-arith -Wcast-align -Wwrite-strings -Wconversion -Woverloaded-virtual -Wno-sign-compare -Wno-unused -fno-nonansi-builtins -c test.cc -o test.o test.cc: In function 'void save_construct_data(Ar&, const B*, unsigned int) [with Ar = boost::archive::binary_oarchive]': /opt/local/include/boost/serialization/serialization.hpp:148: instantiated from 'void boost::serialization::save_construct_data_adl(Archive&, const T*, unsigned int) [with Archive = boost::archive::binary_oarchive, T = B]' /opt/local/include/boost/archive/detail/oserializer.hpp:179: instantiated from 'void boost::archive::detail::pointer_oserializer<Archive, T>::save_object_ptr(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::binary_oarchive, T = B]' test.cc:60: instantiated from here test.cc:27: error: no match for 'operator<<' in 'ar << (A*)b->B::a' /opt/local/include/boost/archive/detail/interface_oarchive.hpp:63: note: candidates are: Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = A*, Archive = boost::archive::binary_oarchive] make[1]: *** [test.o] Error 1 make[1]: Target `all' not remade because of errors. make: *** [debug] Error 2 Compilation exited abnormally with code 2 at Fri Oct 23 15:25:30 What am I doing wrong? Best regards, Ben

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Boost deserialization of contained object fails when performed from a constructor, but succeeds otherwise.
by bhartsb 28 Oct '09

28 Oct '09

E.G.: ContainingClass::ContainingClass(){ pNA = new objectArray*[NUMBER]; //allocates ptrs ... pNA[ii] = new objectArray(SIZE);//allocates object array, and object array has a std::map "PatternsMap" ... pNA[ii]->load(pNA[ii], "../release/NA Data/NADataa descriptionNA0"); //fails pNA[ii]->PatternsMap.size(); //size = 0 } If I call the following lines of code after the constructor exits then all is well: pNA[ii]->load(pNA[ii], "../release/NA Data/NADataa descriptionNA0"); //succeeds pNA[ii]->PatternsMap.size();//size > 0 Any ideas? Note, that in the constructor example I verified that objectArray was constructed first. -- View this message in context: http://www.nabble.com/Boost-deserialization-of-contained-object-fails-when-… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Thread] io_service post is unsuccessful
by Dylan Klomparens 28 Oct '09

28 Oct '09

I'm trying to figure out why a call to boost::io_service::post might be failing. My program is multithreaded, and has a periodic "timing event" that is triggered. The timing event calls "Service.post(&OnSignal);" to execute a handler, while another thread runs the service. Using this design, I can post an event from any thread without worrying about explicit resource locking. My question is, why does my call to Service.post always fail? I know it is failing because the function that I post never gets called. There is not explicit return code or thrown exception to indicate that there is a problem. Below is an example of what I'm trying to do. Inside main(), there is a commented call to "Service.post(&OnSignal);". Uncommenting that line results in a successful post to the Service, which eventually calls OnSignal, (but only once, obviously). Why does that call work, but not the call in TimingSignalThread()? #include <iostream> #include <boost/asio.hpp> #include <boost/thread/thread.hpp> using namespace std; // This is the service responsible for queuing the events. boost::asio::io_service Service; // This is the function that should be periodically queued by the TimingSignalThread. void OnSignal() { cout << "Got timing signal"; } // This function runs in its own thread, and periodically posts OnSignal() to the Service. void TimingSignalThread() { boost::this_thread::disable_interruption di; // Run until interrupted by <enter>. while(!boost::this_thread::interruption_requested()) { cout << "."; boost::this_thread::sleep(boost::posix_time::millisec(500)); Service.post(&OnSignal); // This post is never successful. } } // This function runs in its own thread, and executes all posts. void ServiceRunner() { Service.run(); } int main() { boost::thread TimingThread(&TimingSignalThread); boost::thread ServiceThread(&ServiceRunner); // Why does 'post()' work here, but not in TimingSignalThread()? // Uncommenting the following line results in a single successful post to OnSignal. // Service.post(&OnSignal); cin.get(); // Press enter to end the program. TimingThread.interrupt(); TimingThread.join(); Service.stop(); ServiceThread.join(); cout << "Joined all threads." << endl; return 0; }

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[Proto] Stuck turning a complex gramamr action to a primitive trasnform
by joel 28 Oct '09

28 Oct '09

I tried to turn a complex grammar transform : struct grammar : or_< ... ,bp::when< bp::nary_expr< bp::_, bp::vararg< grammar > > , bp::_default< grammar > ( _bp::functional::unpack_expr<bp::tag::function>( push_front( bp::_ , bp::_make_terminal ( some_type< bp::tag_of<bp::_> >() ) ) ) ) > into a single primitive transform but I end up stuck cause it seems some of those transform (make_terminal) don't follow the classic proto::result_of/proto namespace acces to compute it's return type and calling it. How should I handle these ? My intuition was that the transform oeprator() will call the equivalent function onto its expr parameters while its result struct compute the result_of by chaining the transform result_of results. Ultimately, I want this to be a tempalte trasnform that take some_type as a parameter : bp::when< bp::nary_expr< bp::_, bp::vararg< grammar > > , traversal<some_type>(bp) > Thanks in advance -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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range_ex
by Richard Ulrich 28 Oct '09

28 Oct '09

Hi list, what's the status of range_ex? I read that it was accepted into boost half a year ago. So, will it make it into 1.41? This week I downloaded it from the boost vault, as the version from the svn sandbox seemed to be outdated. I like it very much so far. Just two remarks/questions: - in my measurements using the piped adapters (filtered / transformed) was on average 4% slower than hand coded loops. Do I have to live with that, or are there any tricks / hints? - I can't use lambdas for the adapters. - transformed expects a result_type that also lambda::res<> doesn't seem to provide. - filtered tries to copy the functor, which in turn lambda doesn't seem to like. Rgds Richard

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Boost.stringalgo
by Marcia Chadly 28 Oct '09

28 Oct '09

Compiling the folowing using is_iless as the predicate for a multi index container results in errors. When is_less is used instead, it compiles fine. typedef mi::multi_index_container< GTLayer, mi::indexed_by< mi::sequenced<>, // list-like index mi::ordered_unique< mi::tag<name>, mi::const_mem_fun<GTLayer, std::string, &GTLayer::GetLayerName>, //std::greater<std::string> ::boost::algorithm::is_iless // names sorted > > > layer_container; The error messages are - Error 4 error C2440: 'type cast' : cannot convert from 'std::basic_string<_Elem,_Traits,_Ax>' to 'unsigned char' C:\Program Files\Microsoft Visual Studio 8\VC\include\xlocale 561 Error 3 error C2440: 'type cast' : cannot convert from 'unsigned char' to 'std::basic_string<_Elem,_Traits,_Ax>' C:\Program Files\Microsoft Visual Studio 8\VC\include\xlocale 583 Is this an include problem? I have tried the following includes - #include <boost/multi_index_container.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/sequenced_index.hpp> #include <boost/algorithm/string/compare.hpp> #include <boost/algorithm/string.hpp> #include <boost/algorithm/string/predicate.hpp> #include <map> #include <string> #include <cwchar> #include <locale> Thanks - Marcia

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