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  • boost spirit semantic action parameters

    - by lurscher
    Hi, in this article about boost spirit semantic actions it is mentioned that There are actually 2 more arguments being passed: the parser context and a reference to a boolean ‘hit’ parameter. The parser context is meaningful only if the semantic action is attached somewhere to the right hand side of a rule. We will see more information about this shortly. The boolean value can be set to false inside the semantic action invalidates the match in retrospective, making the parser fail. All fine, but i've been trying to find an example passing a function object as semantic action that uses the other parameters (parser context and hit boolean) but i haven't found any. I would love to see an example using regular functions or function objects, as i barely can grok the phoenix voodoo

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  • Pass by reference in Boost::Python

    - by Fabzter
    Hi everybody. Consider something like: struct Parameter { int a; Parameter(){a = 0} void setA(int newA){a = newA;} }; struct MyClass { void changeParameter(Parameter &p){ p.setA(-1);} }; Well, let's fast forward, and imagine I already wrapped those classes, exposing everything to python, and imagine also I instantiate an object of Parameter in the C++ code, which I pass to the python script, and that python script uses a MyClass object to modify the instance of Parameter I created at the beginning in the C++ code. After that code executes, in C++ Parameter instance is unchanged!!! This means it was passed by value (or something alike :S), not by reference. But I thought I declared it to be passed by reference... I can't seem to find Boost::Python documentation about passing by reference (although there seems to be enough doc about returning by reference...). Can anyone give some hint or pointer please?

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  • Boost bind function

    - by Gokul
    Hi, I have a abstract base class A and a set of 10 derived classes. The infix operator is overloaded in all of the derived classes class A{ void printNode( std::ostream& os ) { this->printNode_p(); } void printNode_p( std::ostream& os ) { os << (*this); } }; There is a container which stores the base class pointers. I want to use boost::bind function to call the overloaded infix operator in each of its derived class. I have written like this std::vector<A*> m_args .... std::ostream os; for_each( m_args.begin(), m_args.end(), bind(&A::printNode, _1, os) ); What is the problem with this code? Thanks, Gokul.

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  • Boost.Program_Options not working with short options

    - by inajamaica
    I have the following options_description: po::options_description config("Configuration File or Command Line"); config.add_options() ("run-time,t", po::value(&runTime_)-default_value(1440.0), "set max simulation duration") ("starting-iteration,i", po::value(&startingIteration_)-default_value(1), "set starting simulation iteration") ("repetitions,r", po::value(&repetitions_)-default_value(100), "set number of iterations") ... ; As you can see the three shown have a long,short names employed. The long versions all work. However, none of the short ones do, and each time I try a -t 12345.0 or a -i 12345, etc., I get the following from Program_Options: std::logic_error: in option 'starting-iteration': invalid option value I'm using Boost 1.42 on Win32. Any thoughts on what might be going on here? Thanks!

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  • Using STL/Boost to initialize a hard-coded set<vector<int> >

    - by Hooked
    Like this question already asked, I'd like to initialize a container using STL where the elements are hard-coded in the cleanest manner possible. In this case, the elements are a doubly nested container: set<vector<int> > A; And I'd like (for example) to put the following values in: A = [[0,0,1],[0,1,0],[1,0,0],[0,0,0]]; C++0x fine, using g++ 4.4.1. STL is preferable as I don't use Boost for any other parts of the code (though I wouldn't mind an example with it!).

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  • pushing back an boost::ptr_vector<...>::iterator in another boost::ptr_vector?

    - by Ethan Nash
    Hi all, I have the following code (just typed it in here, might have typos or stuff): typedef boost::ptr_vector<SomeClass> tvec; tvec v; // ... fill v ... tvec vsnap; for(tvec::iterator it = v.begin(); it != v.end(); ++it) { if((*v).anyCondition) vsnap.push_back( it ); // (*it) or &(*it) doesn't work } My problem is now that i cant push_back an iterator in any way, I just don't get the pointer out of the iterator. Is there an easy way i didnt see, or are boosts ptr_vector the false choice for this case? Thanks in advance.

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  • Boost python module building

    - by Ockonal
    Hello, I'm using boost.python and I need in building some module for it. I have an some_module.cpp file in project. How can I build it correctly to the shared library for using it with python in future? When I learned it, I had only 1 file and I built it with command: gcc -shared -Wl,-soname,hello.so -o hello.so test.cpp -I /usr/include/python2.6/ -lboost_python And I don't know how to configure it in whole project. I'm using Eclipse and Code::Blocks IDEs.

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  • Boost graph libraries: setting edge weight values

    - by AndyUK
    I am investigating the use of the boost graph libraries in order to apply them to various network problems I have in mind. In the examples I have been looking at the graph edge values ("weights") are always initialized as integers, such as in these Bellman-Ford and Kruskal algorithms eg: int weights[] = { 1, 1, 2, 7, 3, 1, 1, 1 }; My problem is if I try and change the weights to double, I get a heap of warning messages about conversions etc, which so far I have not been able to figure out how to overcome. Does anyone see a way around this?

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  • Passing Boost uBLAS matrices to OpenGL shader

    - by AJM
    I'm writing an OpenGL program where I compute my own matrices and pass them to shaders. I want to use Boost's uBLAS library for the matrices, but I have little idea how to get a uBLAS matrix into OpenGL's shader uniform functions. matrix<GLfloat, column_major> projection(4, 4); // Fill matrix ... GLuint projectionU = glGetUniformLocation(shaderProgram, "projection"); glUniformMatrix4fv(projectionU, 1, 0, (GLfloat *)... Um ...); Trying to cast the matrix to a GLfloat pointer causes an invalid cast error on compile.

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  • Using boost::asio::async_read with stdin?

    - by yeus
    hi poeple.. short question: I have a realtime-simulation which is running as a backround process and is connected with pipes to the calling pogramm. I want to send commands to that process using stdin to get certain information from it via stdout. Now because it is a real-time process, it has to be a non blocking input. Is boost::asio::async_read in conjunction with iostream::cin a good idea for this task? how would I use that function if it is feasible? Any more suggestions?

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  • Sample the deltas between values using boost::accumulators

    - by Checkers
    I have a data set with N integers (say, 13, 16, 17, 20) where each next sample is incremented by some value (3, 1, 3 in this case) and I want to use boost::accumulators::accumulator_set to find various statistics of the second sequence. I want to be able to do something like this: accumulator_set< double, features< tag::mean > > acc; ... acc(13); acc(16); acc(17); acc(20); ...BUT sampling the differences instead of the actual values. How can I do that with accumulator_set without keeping track of the last value manually?

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  • basic boost date_time input format question

    - by Chris H
    I've got a pointer to a string, (char *) as input. The date/time looks like this: Sat, 10 Apr 2010 19:30:00 I'm only interested in the date, not the time. I created an "input_facet" with the format I want: boost::date_time::date_input_facet inFmt("%a %d %b %Y"); but I'm not sure what to do with it. Ultimately I'd like to create a date object from the string. I'm pretty sure I'm on the right track with that input facet and format, but I have no idea how to use it. Thanks.

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  • unique_ptr boost equivalent?

    - by wowus
    Is there some equivalent class for C++1x's std::unique_ptr in the boost libraries? The behavior I'm looking for is being able to have an exception-safe factory function, like so... std::unique_ptr<Base> create_base() { return std::unique_ptr<Base>(new Derived); } void some_other_function() { std::unique_ptr<Base> b = create_base(); // Do some stuff with b that may or may not throw an exception... // Now b is destructed automagically. }

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  • Boost signals and passing class method

    - by Ockonal
    Hello, I've defined some signal: typedef boost::signals2::signal<void (int temp)> SomeSig; typedef SomeSig::slot_type SomeSigType; I have some class: class SomeClass { SomeClass() { SomeSig.connect(&SomeClass::doMethod); } void doMethod(const SomeSig &slot); }; And got a lot of errors: error: ‘BOOST_PP_ENUM_SHIFTED_PARAMS_M’ was not declared in this scope error: ‘T’ was not declared in this scope error: a function call cannot appear in a constant-expression error: a function call cannot appear in a constant-expression error: template argument 1 is invalid error: ‘BOOST_SIGNALS2_MISC_STATEMENT’ has not been declared error: expected identifier before ‘~’ token error: expected ‘)’ before ‘~’ token error: expected ‘;’ before ‘~’ token

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  • Boost multiindex complex struct

    - by StrifeLow
    In boost multiindex example complex_structs, it use one key in the car_manufacturer struct for car_table. If car_manufacturer have been modify to have 2 ID struct car_manufacturer { std::string name; int cm_code; car_manufacturer(const std::string& name_, const int& cm_code_):name(name_), cm_code(cm_code_){} }; What will be the key_from_key struct looks like? Have try to add another KeyExtractor or use composite index inside key_from_key, but still cannot compile. Please help on this. Thanks.

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  • number of months between two dates - using boost's date

    - by MartinP
    I've used boost::gregorian::date a bit now. I can see that there are the related months & years & weeks duration types. I can see how to use known durations to advance a given date. Qu: But how can I get the difference between two dates in months (or years or weeks) ? I was hoping to find a function like: template<typename DURATION> DURATION date_diff<DURATION>(const date& d1,const date& d2); There would need to be some handling of rounding too.

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  • Boost singleton and undefined reference

    - by Ockonal
    Hello, I globally use singleton pattern in my project. To make it easier - boost::singleton. Current project uses Ogre3d library for rendering. Here is some class: class GraphicSystem : public singleton<GraphicSystem> { private: Ogre::RenderWindow *mWindow; public: Ogre::RenderWindow *getWindow() const { return mWindow; } }; In GraphicSystem constructor I fill the mWindow value: mWindow = mRoot->createRenderWindow(...); I cheked it, everything makes normally. So, now I have to use handler for the window in input system (to get window handle). Somewhere else in another class: Ogre::RenderWindow *temp = GraphicSystem::get_mutable_instance().getWindow(); GraphicSystem::get_mutable_instance().getWindow()->getCustomAttribute("WINDOW", &mWindowHandle); temp is 0x00, and there is segfault at last line (getting custon attribute). I can't understand, why does singleton returns undefined pointer for the window. All another singleton-based classes work well.

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  • C++ boost ublas + units dimension constraints

    - by aaa
    hello. I am seeking advice on design/general idea on how to force matrix dimension constraints on ublas matrix/vector possibly using boost units. For example, let matrix A have dimensions of time x force (for example) // does not have dimensions, time x force and force x time are not distinguished. matrix<double> A; //something like? dimension<time, force, matrix<double> > A; dimension<force, time, matrix<double> > B = trans(A); have you done something like this or do you have some good idea about how to organize such constraints? Thank you

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  • Purpose of boost::checked_delete

    - by Channel72
    I don't understand the purpose of boost::checked_delete. The documentation says: The C++ Standard allows, in 5.3.5/5, pointers to incomplete class types to be deleted with a delete-expression. When the class has a non-trivial destructor, or a class-specific operator delete, the behavior is undefined. Some compilers issue a warning when an incomplete type is deleted, but unfortunately, not all do, and programmers sometimes ignore or disable warnings. The supplied function and class templates can be used to prevent these problems, as they require a complete type, and cause a compilation error otherwise. So the C++ standard allows you to delete incomplete types, which causes undefined behavior if the type has a non-trivial destructor. What? How can an incomplete type have any destructor at all? Isn't an incomplete type just a prototype?

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  • [C++] Boost test: catch user defined exceptions

    - by user231536
    If I have user defined exceptions in my code, I can't get Boost test to consider them as failures. For example, BOOST_AUTO_TEST_CASE_EXPECTED_FAILURES(MyTest,1) BOOST_AUTO_TEST_CASE(MyTest) { // code which throws user defined exception, not derived from std::exception. } I get a generic message: Caught exception: .... unknown location(0):.... It does not recognize this error as a failure since it is not a std::exception. So it does not honor the expected_failures clause. How do I enforce that the piece of code should always throw an exception? THis seems to be a useful thing to want. In case future code changes cause the code to pass and the exception is not thrown, I want to know that.

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  • Boost singleton trouble

    - by Ockonal
    Hi guys, I have some class which uses boost singleton. It calls some function from own c++ library. This library is written in make file as dependence. Now I have another singleton class and it should call first singleton class. After this code I got linkers error about undefined references for functions which are used in first singleton. When I remove calling first singleton class from second the errors remove. Maybe there is something wrong?

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  • Subtracting months/years from boost::posix_time::ptime

    - by Zack
    I have a boost::posix_time::ptime that points to March 31st 2010 like this: ptime p(date(2010, Mar, 31)); I would like to subtract a month (and possibly years) from this date. From the docs I see these two operators: ptime operator-(time_duration) and ptime operator-(days) but none of them can work with months/years. If I try and do: time_duration duration = hours(24 * 30); ptime pp = p - duration; I'm getting March 1st and if I'm trying: ptime pp = p - days(30); I'm still getting March 1st, while I'd like to get February 28th. How can I achieve my desired result? (I would like to get the desired result also when subtracting a month from March 28, 29, 30)

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  • Client-server application between two computers in the same network (using boost::asio)

    - by Edwin
    I'm trying to set up a basic communication between my desktop PC and my laptop (latter one using wireless connection) both being in the same network, using the boost::asio tutorials: synchronous client and synchronous server (in c++). When I run both the server and client on the same machine (using the localhost and the datetime port as parameters), it works splendidly. But if I try to set up the laptop as server (tested it with netstat -anb from the command prompt, it is indeed running and listening to port 13 as it's supposed to, and I even deactivated the firewall to make sure it doesn't cause any problems), I cannot connect to it with the client (set up on the PC), no matter what IP I tried (localhost, and basically any IPs that ipconfig -all gave me). So no matter what I tried, I cannot find the correct address that which the client can use to connect to the server. Could anyone help me please?

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  • forEach and Facelets - a bugfarm just waiting for harvest

    - by Duncan Mills
    An issue that I've encountered before and saw again today seems worthy of a little write-up. It's all to do with a subtle yet highly important difference in behaviour between JSF 2 running with JSP and running on Facelets (.jsf pages). The incident I saw today can be seen as a report on the ADF EMG bugzilla (Issue 53) and in a blog posting by Ulrich Gerkmann-Bartels who reported the issue to the EMG. Ulrich's issue nicely shows how tricky this particular gochya can be. On the surface, the problem is squarely the fault of MDS but underneath MDS is, in fact, innocent. To summarize the problem in a simpler testcase than Ulrich's example, here's a simple fragment of code: <af:forEach var="item" items="#{itemList.items}"> <af:commandLink id="cl1" text="#{item.label}" action="#{item.doAction}"  partialSubmit="true"/> </af:forEach> Looks innocent enough right? We see a bunch of links printed out, great. The issue here though is the id attribute. Logically you can kind of see the problem. The forEach loop is creating (presumably) multiple instances of the commandLink, but only one id is specified - cl1. We know that IDs have to be unique within a JSF component tree, so that must be a bad thing?  The problem is that JSF under JSP implements some hacks when the component tree is generated to transparently fix this problem for you. Behind the scenes it ensures that each instance really does have a unique id. Really nice of it to do so, thank you very much. However, (you could see this coming), the same is not true when running with Facelets  (this is under 11.1.2.n)  in that case, what you put for the id is what you get, and JSF does not mess around in the background for you. So you end up with a component tree that contains duplicate ids which are only created at runtime.  So subtle chaos can ensue.  The symptoms are wide and varied, from something pretty obscure such as the combination Ulrich uncovered, to something as frustrating as your ActionListener just not being triggered. And yes I've wasted hours on just such an issue.  The Solution  Once you're aware of this one it's really simple to fix it, there are two options: Remove the id attribute on components that will cause some kind of submission within the forEach loop altogether and let JSF do the right thing in generating them. Then you'll be assured of uniqueness. Use the var attribute of the loop to generate a unique id for each child instance.  for example in the above case: <af:commandLink id="cl1_#{item.index}" ... />.  So one to watch out for in your upgrades to JSF 2 and one perhaps, for your coding standards today to prepare you for. For completeness, here's the reference to the underlying JSF issue that's at the heart of this: JAVASERVERFACES-1527

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  • How to include only BOOST smart pointer codes into a project?

    - by afriza
    What are best practices to include boost smart pointer library only without adding all boost libraries into the project? I only want boost smart pointer library in my project and I don't want to check in/commit 200 MB source codes (boost 1.42.0) into my project repository just for that. What more, my windows mobile project itself doesn't even reach 10% of that size!

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