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  • Boost BGL thread safety

    - by Budzoli
    Hi! I'd like multiple threads to use the dijkstra_shortest_paths and astar_search functions of the BGL, and then read the property maps of the result vertices and edges. I'm wondering wether I should use mutexes to ensure thread-safety. So here are my questions: 1., Are the dijkstra_shortest_paths and astar_search functions of the Boost.Graph thread safe? 2., If I only try to read the property maps of the graph from multiple threads, do I need to worry about thread safety?

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  • Boost.Test: Looking for a working non-Trivial Test Suite Example / Tutorial

    - by Robert S. Barnes
    The Boost.Test documentation and examples don't really seem to contain any non-trivial examples and so far the two tutorials I've found here and here while helpful are both fairly basic. I would like to have a master test suite for the entire project, while maintaining per module suites of unit tests and fixtures that can be run independently. I'll also be using a mock server to test various networking edge cases. I'm on Ubuntu 8.04, but I'll take any example Linux or Windows since I'm writing my own makefiles anyways.

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  • Pretty printing boost::unordered_map on gdb

    - by scooterman
    Hi all, recently I've started to use the excellent boost::unordered_map on my system, but got one drawback: I couldn't figure how to inspect its contents. Printing it on gdb gives me a table_ and a buckets_, but haven't found where are the items. Anyone has a clue about this?

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  • Why isn't the boost::shared_ptr -> operator inlined?

    - by Alan
    Since boost::shared_ptr could be called very frequently and simply returns a pointer, isn't the -> operator a good candidate for being inlined? T * operator-> () const // never throws { BOOST_ASSERT(px != 0); return px; } Would a good compiler automatically inline this anyway? Should I lose any sleep over this? :-)

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  • Boost multi_index ordered_unique Median Value

    - by Autopulated
    I would like to quickly retrieve the median value from a boost multi_index container with an ordered_unique index, however the index iterators aren't random access (I don't understand why they can't be, though this is consistent with std::set...). Is there a faster/neater way to do this other than incrementing an iterator container.size() / 2 times?

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  • Direct boost serialization to char array

    - by scooterman
    Hi all, Boost serialization doc's assert that the way to serialize/deserialize items is using a binary/text archive with a stream on the underlying structure. This works fine if I wan't to use the serialized data as an std::string, but my intention is to convert it directly to a char* buffer. How can I achieve this without creating a temporary string?

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  • C++ boost thread reusing threads

    - by aaa
    hi. I am trying to accomplish something like this: thread t; // create/initialize thread t.launch(); // launch thread. t.wait(); // wait t.launch(); // relaunch the same thread How to go about implementing something like this using boost threads? in essence, I need persistent relaunch-able thread. Thanks

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  • C++ boost wave, scoped macro

    - by aaa
    hello. Is it possible to have scoped macros using custom defined macros through boost wave? I know it should a possible with C++0x however I am working with regular C++. If it is possible, can you provide link or reference how to accomplish this? Thanks

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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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  • 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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  • How can I use nested Async (WCF) calls within foreach loops in Silverlight ?

    - by Peter St Angelo
    The following code contains a few nested async calls within some foreach loops. I know the silverlight/wcf calls are called asyncrously -but how can I ensure that my wcfPhotographers, wcfCategories and wcfCategories objects are ready before the foreach loop start? I'm sure I am going about this all the wrong way -and would appreciate an help you could give. private void PopulateControl() { List<CustomPhotographer> PhotographerList = new List<CustomPhotographer>(); proxy.GetPhotographerNamesCompleted += proxy_GetPhotographerNamesCompleted; proxy.GetPhotographerNamesAsync(); //for each photographer foreach (var eachPhotographer in wcfPhotographers) { CustomPhotographer thisPhotographer = new CustomPhotographer(); thisPhotographer.PhotographerName = eachPhotographer.ContactName; thisPhotographer.PhotographerId = eachPhotographer.PhotographerID; thisPhotographer.Categories = new List<CustomCategory>(); proxy.GetCategoryNamesFilteredByPhotographerCompleted += proxy_GetCategoryNamesFilteredByPhotographerCompleted; proxy.GetCategoryNamesFilteredByPhotographerAsync(thisPhotographer.PhotographerId); // for each category foreach (var eachCatergory in wcfCategories) { CustomCategory thisCategory = new CustomCategory(); thisCategory.CategoryName = eachCatergory.CategoryName; thisCategory.CategoryId = eachCatergory.CategoryID; thisCategory.SubCategories = new List<CustomSubCategory>(); proxy.GetSubCategoryNamesFilteredByCategoryCompleted += proxy_GetSubCategoryNamesFilteredByCategoryCompleted; proxy.GetSubCategoryNamesFilteredByCategoryAsync(thisPhotographer.PhotographerId,thisCategory.CategoryId); // for each subcategory foreach(var eachSubCatergory in wcfSubCategories) { CustomSubCategory thisSubCatergory = new CustomSubCategory(); thisSubCatergory.SubCategoryName = eachSubCatergory.SubCategoryName; thisSubCatergory.SubCategoryId = eachSubCatergory.SubCategoryID; } thisPhotographer.Categories.Add(thisCategory); } PhotographerList.Add(thisPhotographer); } PhotographerNames.ItemsSource = PhotographerList; } void proxy_GetPhotographerNamesCompleted(object sender, GetPhotographerNamesCompletedEventArgs e) { wcfPhotographers = e.Result.ToList(); } void proxy_GetCategoryNamesFilteredByPhotographerCompleted(object sender, GetCategoryNamesFilteredByPhotographerCompletedEventArgs e) { wcfCategories = e.Result.ToList(); } void proxy_GetSubCategoryNamesFilteredByCategoryCompleted(object sender, GetSubCategoryNamesFilteredByCategoryCompletedEventArgs e) { wcfSubCategories = e.Result.ToList(); }

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  • How do I use foreach with QDomNodeList in Qt?

    - by Venemo
    Hi Everyone, I'm new to Qt and I'm learning something new every day. Currently, I'm developing a small application for my Nokia N900 in my free time. Everything is fine, I am able to compile and run Maemo applications on the device. I've just learned about the foreach keyword in Qt. (I know it is not in C++, so I didn't think about it until I accidentally stumbled upon a Qt doc that mentioned it.) So, I decided to change my quite annoying and unreadable loops to foreach, but I failed with this: QDomNodeList list = doc.lastChild().childNodes().at(1).firstChild().childNodes(); for (int x = 0; x < list.count(); x++) { QDomElement node = list.at(x).toElement(); // Do something with node } This is how I tried: foreach (QDomElement node, doc.lastChild().childNodes().at(1).firstChild().childNodes()) { // Do something with node } For some reason the above code doesn't even compile. I get cryptic error messages from the compiler. Could someone please explain to me how to get it right? If the foreach loop doesn't support QDomNodeList, is there a way of handling XML files that do support foreach?

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  • Can I use foreach to return only a certain type from a collection?

    - by RoboShop
    If I enter the code below, I get an error. Basically, the foreach will break when it comes across a Control that isn't a label. foreach (Label currControl in this.Controls()) { ... } I have to do something like this. foreach (Control currControl in this.Controls()) { if(typeof(Label).Equals(currControl.GetType())){ ... } } can anyone think of a better way of doing it without me needing to check the type? Can I somehow get foreach to skip the objects that aren't Labels?

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  • what use does the javascript forEach method have (that map can't do)?

    - by JohnMerlino
    Hey all, The only difference I see in map and foreach is that map is returning an array and foreach is not. However, I don't even understand the last line of the foreach method "func.call(scope, this[i], i, this);". For example, isn't "this" and "scope" referring to same object and isn't this[i] and i referring to the current value in the loop? I noticed on another post someone said "Use forEach when you want to do something on the basis of each element of the list. You might be adding things to the page, for example. Essentially, it's great for when you want "side effects". I don't know what is meant by side effects. Array.prototype.map = function(fnc) { var a = new Array(this.length); for (var i = 0; i < this.length; i++) { a[i] = fnc(this[i]); } return a; } Array.prototype.forEach = function(func, scope) { scope = scope || this; for (var i = 0, l = this.length; i < l; i++) func.call(scope, this[i], i, this); } Finally, are there any real uses for these methods in javascript (since we aren't updating a database) other than to manipulate numbers like this: alert([1,2,3,4].map(function(x){ return x + 1})); //this is the only example I ever see of map in javascript. Thanks for any reply.

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  • XNA 2D Top Down game - FOREACH didn't work for checking Enemy and Switch-Tile

    - by aldroid16
    Here is the gameplay. There is three condition. The player step on a Switch-Tile and it became false. 1) When the Enemy step on it (trapped) AND the player step on it too, the Enemy will be destroyed. 2) But when the Enemy step on it AND the player DIDN'T step on it too, the Enemy will be escaped. 3) If the Switch-Tile condition is true then nothing happened. The effect is activated when the Switch tile is false (player step on the Switch-Tile). Because there are a lot of Enemy and a lot of Switch-Tile, I have to use foreach loop. The problem is after the Enemy is ESCAPED (case 2) and step on another Switch-Tile again, nothing happened to the enemy! I didn't know what's wrong. The effect should be the same, but the Enemy pass the Switch tile like nothing happened (They should be trapped) Can someone tell me what's wrong? Here is the code : public static void switchUpdate(GameTime gameTime) { foreach (SwitchTile switch in switchTiles) { foreach (Enemy enemy in EnemyManager.Enemies) { if (switch.Active == false) { if (!enemy.Destroyed) { if (switch.IsCircleColliding(enemy.EnemyBase.WorldCenter, enemy.EnemyBase.CollisionRadius)) { enemy.EnemySpeed = 10; //reducing Enemy Speed if it enemy is step on the Tile (for about two seconds) enemy.Trapped = true; float elapsed = (float)gameTime.ElapsedGameTime.Milliseconds; moveCounter += elapsed; if (moveCounter> minMoveTime) { //After two seconds, if the player didn't step on Switch-Tile. //The Enemy escaped and its speed back to normal enemy.EnemySpeed = 60f; enemy.Trapped = false; } } } } else if (switch.Active == true && enemy.Trapped == true && switch.IsCircleColliding(enemy.EnemyBase.WorldCenter, enemy.EnemyBase.CollisionRadius) ) { //When the Player step on Switch-Tile and //there is an enemy too on this tile which was trapped = Destroy Enemy enemy.Destroyed = true; } } } }

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