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  • any stl/boost functors to call operator()

    - by Voivoid
    template <typename T> struct Foo { void operator()(T& t) { t(); } }; Is there any standart or boost functor with the similar implementation? I need it to iterate over container of functors: std::for_each(beginIter, endIter, Foo<Bar>()); Or maybe there are other way to do it?

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  • Mixing C and C++, raw pointers and (boost) shared pointers

    - by oompahloompah
    I am working in C++ with some legacy C code. I have a data structure that (during initialisation), makes a copy of the structure pointed to a ptr passed to its initialisation pointer. Here is a simplification of what I am trying to do - hopefully, no important detail has been lost in the "simplification": /* C code */ typedef struct MyData { double * elems; unsigned int len; }; int NEW_mydata(MyData* data, unsigned int len) { // no error checking data->elems = (double *)calloc(len, sizeof(double)); return 0; } typedef struct Foo { MyData data data_; }; void InitFoo(Foo * foo, const MyData * the_data) { //alloc mem etc ... then assign the STRUCTURE foo.data_ = *thedata ; } C++ code ------------- typedef boost::shared_ptr<MyData> MyDataPtr; typedef std::map<std::string, MyDataPtr> Datamap; class FooWrapper { public: FooWrapper(const std::string& key) { MyDataPtr mdp = dmap[key]; InitFoo(&m_foo, const_cast<MyData*>((*mdp.get()))); } ~FooWrapper(); double get_element(unsigned int index ) const { return m_foo.elems[index]; } private: // non copyable, non-assignable FooWrapper(const FooWrapper&); FooWrapper& operator= (const FooWrapper&); Foo m_foo; }; int main(int argc, char *argv[]) { MyData data1, data2; Datamap dmap; NEW_mydata(&data1, 10); data1->elems[0] = static_cast<double>(22/7); NEW_mydata(&data2, 42); data2->elems[0] = static_cast<double>(13/21); boost::shared_ptr d1(&data1), d2(&data2); dmap["data1"] = d1; dmap["data2"] = d2; FooWrapper fw("data1"); //expect 22/7, get something else (random number?) double ret fw.get_element(0); } Essentially, what I want to know is this: Is there any reason why the data retrieved from the map is different from the one stored in the map?

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  • Boost::asio::endpoint::size() and resize()

    - by p00ya
    hi. I was reading the boost endpoint documentation and saw size() and resize() member funcs. the documentation says: Gets the underlying size of the endpoint in the native type. what does this size represent and where can it be used/resized ? thanks.

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  • Custom InputIterator for Boost graph (BGL)

    - by Shadow
    Hi, I have a graph with custom properties to the vertices and edges. I now want to create a copy of this graph, but I don't want the vertices to be as complex as in the original. By this I mean that it would suffice that the vertices have the same indices (vertex_index_t) as they do in the original graph. Instead of doing the copying by hand I wanted to use the copy-functionality of boost::adjacency_list (s. http://www.boost.org/doc/libs/1_37_0/libs/graph/doc/adjacency_list.html): template <class EdgeIterator> adjacency_list(EdgeIterator first, EdgeIterator last, vertices_size_type n, edges_size_type m = 0, const GraphProperty& p = GraphProperty()) The description there says: The EdgeIterator must be a model of InputIterator. The value type of the EdgeIterator must be a std::pair, where the type in the pair is an integer type. The integers will correspond to vertices, and they must all fall in the range of [0, n). Unfortunately I have to admit that I don't quite get it how to define an EdgeIterator that is a model of InputIterator. Here's what I've succeded so far: template< class EdgeIterator, class Edge > class MyEdgeIterator// : public input_iterator< std::pair<int, int> > { public: MyEdgeIterator() {}; MyEdgeIterator(EdgeIterator& rhs) : actual_edge_it_(rhs) {}; MyEdgeIterator(const MyEdgeIterator& to_copy) {}; bool operator==(const MyEdgeIterator& to_compare) { return actual_edge_it_ == to_compare.actual_edge_it_; } bool operator!=(const MyEdgeIterator& to_compare) { return !(*this == to_compare); } Edge operator*() const { return *actual_edge_it_; } const MyEdgeIterator* operator->() const; MyEdgeIterator& operator ++() { ++actual_edge_it_; return *this; } MyEdgeIterator operator ++(int) { MyEdgeIterator<EdgeIterator, Edge> tmp = *this; ++*this; return tmp; } private: EdgeIterator& actual_edge_it_; } However, this doesn't work as it is supposed to and I ran out of clues. So, how do I define the appropriate InputIterator?

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  • Is Using Tuples in my .NET 4.0 Code a Poor Design Decision?

    - by Jason Webb
    With the addition of the Tuple class in .net 4, I have been trying to decide if using them in my design is a bad choice or not. The way I see it, a Tuple can be a shortcut to writing a result class (I am sure there are other uses too). So this: public class ResultType { public string StringValue { get; set; } public int IntValue { get; set; } } public ResultType GetAClassedValue() { //..Do Some Stuff ResultType result = new ResultType { StringValue = "A String", IntValue = 2 }; return result; } Is equivalent to this: public Tuple<string, int> GetATupledValue() { //...Do Some stuff Tuple<string, int> result = new Tuple<string, int>("A String", 2); return result; } So setting aside the possibility that I am missing the point of Tuples, is the example with a Tuple a bad design choice? To me it seems like less clutter, but not as self documenting and clean. Meaning that with the type ResultType, it is very clear later on what each part of the class means but you have extra code to maintain. With the Tuple<string, int> you will need to look up and figure out what each Item represents, but you write and maintain less code. Any experience you have had with this choice would be greatly appreciated.

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  • How to pass user-defined structs using boost mpi

    - by lava
    I am trying to send a user-defined structure named ABC using boost::mpi::send () call. The given struct contains a vector "data" whose size is determined at runtime. Objects of struct ABC are sent by master to slaves. But the slaves need to know the size of vector "data" so that the sufficient buffer is available on the slave to receive this data. I can work around it by sending the size first and initialize sufficient buffer on the slave before receiving the objects of struct ABC. But that defeats the whole purpose of using STL containers. Does anyone know of a better way to do handle this ? Any suggestions are greatly appreciated. Here is a sample code that describes the intent of my program. This code fails at runtime due to above mentioned reason. struct ABC { double cur_stock_price; double strike_price; double risk_free_rate; double option_price; std::vector <char> data; }; namespace boost { namespace serialization { template<class Archive> void serialize (Archive &ar, struct ABC &abc, unsigned int version) { ar & abc.cur_stock_price; ar & abc.strike_price; ar & abc.risk_free_rate; ar & abc.option_price; ar & bopr.data; } } } BOOST_IS_MPI_DATATYPE (ABC); int main(int argc, char* argv[]) { mpi::environment env (argc, argv); mpi::communicator world; if (world.rank () == 0) { ABC abc_obj; abc.cur_stock_price = 1.0; abc.strike_price = 5.0; abc.risk_free_rate = 2.5; abc.option_price = 3.0; abc_obj.data.push_back ('a'); abc_obj.data.push_back ('b'); world.send ( 1, ANY_TAG, abc_obj;); std::cout << "Rank 0 OK!" << std::endl; } else if (world.rank () == 1) { ABC abc_obj; // Fails here because abc_obj is not big enough world.recv (0,ANY_TAG, abc_obj;); std::cout << "Rank 1 OK!" << std::endl; for (int i = 0; i < abc_obj;.data.size(); i++) std::cout << i << "=" << abc_obj.data[i] << std::endl; } MPI_Finalize(); return 0; }

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  • How to implement tokenizer.rbegin() and rend() for boost::tokenizer ?

    - by Chan
    Hello everyone, I'm playing around with boost::tokenizer however I realize that it does not support rbegin() and rend(). I would like to ask how can I add these two functions to the existing class? This is from the boost site: #include <iostream> #include <string> #include <boost/tokenizer.hpp> using namespace std; using namespace boost; int main() { string str( "12/12/1986" ); typedef boost::tokenizer<boost::char_separator<char>> tokenizer; boost::char_separator<char> sep( "/" ); tokenizer tokens( str, sep ); cout << *tokens.begin() << endl; // cout << *tokens.rbegin() << endl; How could I implement this? return 0; }

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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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