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  • boost.serialization and lazy initialization

    - by niXman
    i need to serialize directory tree. i have no trouble with this type: std::map< std::string, // string(path name) std::vector<std::string> // string array(file names in the path) > tree; but for the serialization the directory tree with the content i need other type: std::map< std::string, // string(path name) std::vector< // files array std::pair< std::string, // file name std::vector< // array of file pieces std::pair< // <<<<<<<<<<<<<<<<<<<<<< for this i need lazy initialization std::string, // piece buf boost::uint32_t // crc32 summ on piece > > > > > tree; how can i serialize the object of type "std::pair" in the moment of its serialization?

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  • Boost.Program_options fixed number of tokens

    - by kloffy
    Boost.Program_options provides a facility to pass multiple tokens via command line arguments as follows: std::vector<int> nums; po::options_description desc("Allowed options"); desc.add_options() ("help", "Produce help message.") ("nums", po::value< std::vector<int> >(&nums)->multitoken(), "Numbers.") ; po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); po::notify(vm); However, what is the preferred way of accepting only a fixed number of arguments? The only solution I could come is to manually assign values: int nums[2]; po::options_description desc("Allowed options"); desc.add_options() ("help", "Produce help message.") ("nums", "Numbers.") ; po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); if (vm.count("nums")) { // Assign nums } This feels a bit clumsy. Is there a better solution?

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  • Boost Solr results based on the field that contained the hit

    - by TomFor
    Hi, I was browsing the web looking for a indexing and search framework and stumbled upon Solr. A functionality that we abolutely need is to boost results based on what field contained the hit. A small example: Consider a record like this: <movie> <title>The Dark Knight</title> <alternative_title>Batman Begins 2</alternative_title> <year>2008</year> <director>Christopher Nolan</director> <plot>Batman, Gordon and Harvey Dent are forced to deal with the chaos unleashed by an anarchist mastermind known only as the Joker, as it drives each of them to their limits.</plot> </movie> I want to combine for example the title, alternative_title and plot fields into one search field, which isn't too difficult after looking at the Solr/Lucene documentation and tutorials. However I also want that movies that have a hit in title have a higher score than hits on alternative_title and those in their turn should score higher than hits in the plot field. Is there any way to indicate this kond of scoring in the xml or do we need to develop some custom scoring algorythm? Please also note that the example I've givnen is fictional end the real data will probably contain 100+ fields. Thanks in advance, Tom

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  • Using mem_fun_ref with boost::shared_ptr

    - by BlueRaja
    Following the advice of this page, I'm trying to get shared_ptr to call IUnknown::Release() instead of delete: IDirectDrawSurface* dds; ... //Allocate dds return shared_ptr<IDirectDrawSurface>(dds, mem_fun_ref(&IUnknown::Release)); error C2784: 'std::const_mem_fun1_ref_t<_Result,_Ty,_Arg std::mem_fun_ref(Result (_thiscall _Ty::* )(_Arg) const)' : could not deduce template argument for 'Result (_thiscall _Ty::* )(Arg) const' from 'ULONG (_cdecl IUnknown::* )(void)' error C2784: 'std::const_mem_fun_ref_t<_Result,_Ty std::mem_fun_ref(Result (_thiscall _Ty::* )(void) const)' : could not deduce template argument for 'Result (_thiscall _Ty::* )(void) const' from 'ULONG (__cdecl IUnknown::* )(void)' error C2784: 'std::mem_fun1_ref_t<_Result,_Ty,_Arg std::mem_fun_ref(Result (_thiscall _Ty::* )(_Arg))' : could not deduce template argument for 'Result (_thiscall _Ty::* )(Arg)' from 'ULONG (_cdecl IUnknown::* )(void)' error C2784: 'std::mem_fun_ref_t<_Result,_Ty std::mem_fun_ref(Result (_thiscall _Ty::* )(void))' : could not deduce template argument for 'Result (_thiscall _Ty::* )(void)' from 'ULONG (__cdecl IUnknown::* )(void)' error C2661: 'boost::shared_ptr::shared_ptr' : no overloaded function takes 2 arguments I have no idea what to make of this. My limited template/functor knowledge led me to try typedef ULONG (IUnknown::*releaseSignature)(void); shared_ptr<IDirectDrawSurface>(dds, mem_fun_ref(static_cast<releaseSignature>(&IUnknown::Release))); But to no avail. Any ideas?

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  • Boost Python : How to only expose the constructor of a class with virtual (pure & impure) methods

    - by fallino
    Hello, I'm a newbie with Boost::Python but I tried to search on the web to do so I want to expose a 3rd party library to Python. One of the class of the library (.hpp) is composed of a public constructor with arguments a protected constructor and functions various regular functions various pure virtual functions various non pure virtual functions First, I did not succeed in building it without having errors about this protected constructor. I finally commented it. A first question would be : Is there a way to exclude these protected functions since I don't want to expose them ? (I know it's possible and easy with Py++, but I started without using it) Then I tried to expose all of my functions, beginning with the pure virtual ones (commenting them all except one), which wasn't a success too So I finally decided not to expose these virtual functions (which in fact seems logical...), but, here again, I didn't manage building it with a simple constructor with arguments (without no_init). So my second question is : Is there a way to exclude these virtual functions since I don't want to expose them ? Sorry if it seems trivial but I didn't find anything explicit on the web and I need something rather explicit :). Thanks in advance

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  • compile Boost as static Universal binary lib

    - by Albert
    I want to have a static Universal binary lib of Boost. (Preferable the latest stable version, that is 1.43.0, or newer.) I found many Google hits with similar problems and possible solutions. However, most of them seems outdated. Also none of them really worked. Right now, I am trying sudo ./bjam --toolset=darwin --link=static --threading=multi \ --architecture=combined --address-model=32_64 \ --macosx-version=10.4 --macosx-version-min=10.4 \ install That compiles and install fine. However, the produced binaries seems broken. az@ip245 47 (openlierox) %file /usr/local/lib/libboost_signals.a /usr/local/lib/libboost_signals.a: current ar archive random library az@ip245 49 (openlierox) %lipo -info /usr/local/lib/libboost_signals.a input file /usr/local/lib/libboost_signals.a is not a fat file Non-fat file: /usr/local/lib/libboost_signals.a is architecture: x86_64 az@ip245 48 (openlierox) %otool -hv /usr/local/lib/libboost_signals.a Archive : /usr/local/lib/libboost_signals.a /usr/local/lib/libboost_signals.a(trackable.o): Mach header magic cputype cpusubtype caps filetype ncmds sizeofcmds flags MH_MAGIC_64 X86_64 ALL 0x00 OBJECT 3 1536 SUBSECTIONS_VIA_SYMBOLS /usr/local/lib/libboost_signals.a(connection.o): Mach header magic cputype cpusubtype caps filetype ncmds sizeofcmds flags MH_MAGIC_64 X86_64 ALL 0x00 OBJECT 3 1776 SUBSECTIONS_VIA_SYMBOLS /usr/local/lib/libboost_signals.a(named_slot_map.o): Mach header magic cputype cpusubtype caps filetype ncmds sizeofcmds flags MH_MAGIC_64 X86_64 ALL 0x00 OBJECT 3 1856 SUBSECTIONS_VIA_SYMBOLS /usr/local/lib/libboost_signals.a(signal_base.o): Mach header magic cputype cpusubtype caps filetype ncmds sizeofcmds flags MH_MAGIC_64 X86_64 ALL 0x00 OBJECT 3 1776 SUBSECTIONS_VIA_SYMBOLS /usr/local/lib/libboost_signals.a(slot.o): Mach header magic cputype cpusubtype caps filetype ncmds sizeofcmds flags MH_MAGIC_64 X86_64 ALL 0x00 OBJECT 3 1616 SUBSECTIONS_VIA_SYMBOLS Any suggestion how to get that correct?

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  • Boost Unit testing memory reuse causing tests that should fail to pass

    - by Knyphe
    We have started using the boost unit testing library for a large existing code base, and I have run into some trouble with unit tests incorrectly passing, seemingly due to the reuse of memory on the stack. Here is my situation: BOOST_AUTO_TEST_CASE(test_select_base_instantiation_default) { SelectBase selectBase(); BOOST_CHECK_EQUAL( selectBase.getSelectType(), false); BOOST_CHECK_EQUAL( selectBase.getTypeName(_T("")); BOOST_CHECK_EQUAL( selectBase.getEntityType(), -1); BOOST_CHECK_EQUAL( selectBase.getDataPos(), -1); } BOOST_AUTO_TEST_CASE(test_select_base_instantiation_default) { SelectBase selectBase(true, _T("abc")); BOOST_CHECK_EQUAL( selectBase.getSelectType(), false); BOOST_CHECK_EQUAL( selectBase.getTypeName(_T("abc")); BOOST_CHECK_EQUAL( selectBase.getEntityType(), -1); BOOST_CHECK_EQUAL( selectBase.getDataPos(), -1); } The first test passed correctly, initializing all the variables. The constructor in the second unit test did not correctly set EntityType or DataPosition, but the unit test passed. I was able to get it to fail by placing some variables on the stack in the second test, like so: BOOST_AUTO_TEST_CASE(test_select_base_instantiation_default) { int a, b; SelectBase selectBase(true, _T("abc")); BOOST_CHECK_EQUAL( selectBase.getSelectType(), false); BOOST_CHECK_EQUAL( selectBase.getTypeName(_T("abc")); BOOST_CHECK_EQUAL( selectBase.getEntityType(), -1); BOOST_CHECK_EQUAL( selectBase.getDataPos(), -1); } If there is only one int, only the dataPos CHECK_EQUAL fails, but if there are two, both EntityType and DataPos fail, so it seems pretty clear that this is an issue with the variables being created on the same stack memory or some such. Is there a good way to clear the memory between each unit test, or am I potentially using the library incorrectly or writing bad tests? Any help would be appreciated.

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  • Compose path (with boost::filesystem)

    - by ypnos
    I have a file that describes input data, which is split into several other files. In my descriptor file, I first give the path A that tells where all the other files are found. The originator may set either a relative (to location of the descriptor file) or absolute path. When my program is called, the user gives the name of the descriptor file. It may not be in the current working directory, so the filename B given may also contain directories. For my program to always find the input files at the right places, I need to combine this information. If the path A given is absolute, I need to just that one. If it is relative, I need to concatenate it to the path B (i.e. directory portion of the filename). I thought boost::filesystem::complete may do the job for me. Unfortunately, it seems it is not. I also did not understand how to test wether a path given is absolute or not. Any ideas?

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  • Is boost shared_ptr <XXX> thread safe?

    - by sxingfeng
    I have a question about boost :: shared_ptr. There are lots of thread. class CResource { xxxxxx } class CResourceBase { public: void SetResource(shared_ptr<CResource> res) { m_Res = res; } shared_ptr<CResource> GetResource() { return m_Res; } private: shared_ptr<CResource> m_Res; } CResourceBase base; //---------------------------------------------- Thread A: while (true) { ...... shared_ptr<CResource> nowResource = base.GetResource(); nowResource.doSomeThing(); ... } Thread B: shared_ptr<CResource> nowResource; base.SetResource(nowResource); ... //----------------------------------------------------------- If thread A do not care the nowResource is the newest . Will this part of code have problem? I mean when ThreadB do not SetResource completely, Thread A get a wrong smart point by GetResource? Another question : what does thread-safe mean? If I do not care about whether the resource is newest, will the shared_ptr nowResource crash the program when the nowResource is released or will the problem destroy the shared_point?

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  • boost multi_index partial indexes

    - by Gokul
    Hi, I want to implement inside boost multi-index two sets of keys with same search criteria but different eviction criteria. Say i have two sets of data with same search condition, but one set needs a MRU(Most Recently Used) list of 100 and the other set requires a MRU of 200. Say the entry is like this class Student { int student_no; char sex; std::string address; }; The search criteria is student_no, but for sex='m', we need MRU of 200 and for sex='f', we need a MRU of 100. Now i have a solution where in i introduce a new ordered index to maintain ordering. For example the IndexSpecifierList will be something like this typedef multi_index_container< Student, indexed_by< ordered_unique< member<Student, int, &Student::student_no> >, ordered_unique< composite_key< member<Student, char, &Student::sex>, member<Student, int, &Student::sex_specific_student_counter> > > > > student_set Now everytime, i am inserting a new one, i have to take a equal_range for that using index 2 and remove the oldest one and if something is getting re-used, i have to update it by incrementing the counter. Is there a better solution to this kind of problem? Thanks, Gokul.

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  • How to stop ReSharper from showing error on a lambda expression where Action is expected?

    - by carlmon
    In Silverlight, System.Windows.Threading's Dispatcher.BeginInvoke() takes an Action<T> or a delegate to invoke. .NET allows me to pass just the lambda expression. but ReSharper sees it as an error, saying "Cannot resolve method 'BeginInvoke(lambda expression)'": Dispatcher.BeginInvoke(() => { DoSomething(); }) The error goes away if I explicitly create the Action around the expression like this: Dispatcher.BeginInvoke(new Action<object>(o => { DoSomething(); })); I prefer the least amount of code in this case for the best readability. Is there a way to disable this specific ReSharper error notification? I tried some of the options, but could not find it. Thanks, Carl

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  • What can procs and lambdas do that functions can't in ruby

    - by SecurityGate
    I've been working in Ruby for the last couple weeks, and I've come to the subject of procs, lambdas and blocks. After reading a fair share of examples from a variety of sources, I don't how they're much different from small, specialized functions. It's entirely possible that the examples I've read aren't showing the power behind procs and lambdas. def zero_function(x) x = x.to_s if x.length == 1 return x = "0" + x else return x end end zero_lambda = lambda {|x| x = x.to_s if x.length == 1 return x = "0" + x else return x end } zero_proc = Proc.new {|x| x = x.to_s if x.length == 1 puts x = "0" + x else puts x end } puts zero_function(4) puts zero_lambda.call(3) zero_proc.call(2) This function, proc, and lambda do the exact same thing, just slightly different. Is there any reason to choose one over another?

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  • C++ volatile required when spinning on boost::shared_ptr operator bool()?

    - by JaredC
    I have two threads referencing the same boost::shared_ptr: boost::shared_ptr<Widget> shared; On thread is spinning, waiting for the other thread to reset the boost::shared_ptr: while(shared) boost::thread::yield(); And at some point the other thread will call: shared.reset(); My question is whether or not I need to declare the shared pointer as volatile to prevent the compiler from optimizing the call to shared.operator bool() out of the loop and never detecting the change? I know that if I were simply looping on a variable, waiting for it to reach 0 I would need volatile, but I'm not sure if boost::shared_ptr is implemented in such a way that it is not necessary here.

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  • Looking for mpic++

    - by unknownthreat
    I am following instructions at http://www.boost.org/doc/libs/1_43_0/doc/html/mpi/getting_started.html#mpi.config trying to build Boost MPI .lib files, but I got one problem: I do not have mpic++. Looking at the MPI implementation files such as MPICH2 and Open MPI, I see no mpic++ included at all. Where can I find mpic++?

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  • Intel Core i5-2467m - Turbo Boost not activating?

    - by Trevor Sullivan
    I have a Samsung Series 5 laptop with an Intel Core i5-2467m process @ 1.6Ghz. The processor supports Intel Turbo Boost up to 2.30 Ghz according to the specifications. The i5-2467m is a dual-core process with HyperThreading, so there is a total of four (4) virtual cores in Windows 7 SP1. http://ark.intel.com/products/56858/ I've installed the Intel Turbo Boost Technology Monitor v2.6 to monitor if Turbo Boost is enabled, and set it to "Always On Top." I followed this process to max out the CPU: Open (4x) PowerShell instances Set each instance's affinity to a distinct CPU vCore Ran this code in each instance: while (1 -eq 1) { } Unfortunately, after maxing out all 4 cores, my laptop got hot, but Turbo Boost never kicked in. Any ideas on how to ensure that I'm getting the 2.3Ghz Turbo Boost capability of my laptop?

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  • Using LINQ Lambda Expressions to Design Customizable Generic Components

    LINQ makes code easier to write and maintain by abstracting the data source. It provides a uniform way to handle widely diverse data structures within an application. LINQ’s Lambda syntax is clever enough even to allow you to create generic building blocks with hooks into which you can inject arbitrary functions. Michael Sorens explains, and demonstrates with examples.

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  • Using LINQ Lambda Expressions to Design Customizable Generic Components

    LINQ makes code easier to write and maintain by abstracting the data source. It provides a uniform way to handle widely diverse data structures within an application. LINQ’s Lambda syntax is clever enough to even allow you to create generic building blocks with hooks, into which you can inject arbitrary functions. Michael Sorens explains, and demonstrates with examples. span.fullpost {display:none;}

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  • Are lambda expressions/delegates in C# "pure", or can they be?

    - by Bob
    I recently asked about functional programs having no side effects, and learned what this means for making parallelized tasks trivial. Specifically, that "pure" functions make this trivial as they have no side effects. I've also recently been looking into LINQ and lambda expressions as I've run across examples many times here on StackOverflow involving enumeration. That got me to wondering if parallelizing an enumeration or loop can be "easier" in C# now. Are lambda expressions "pure" enough to pull off trivial parallelizing? Maybe it depends on what you're doing with the expression, but can they be pure enough? Would something like this be theoretically possible/trivial in C#?: Break the loop into chunks Run a thread to loop through each chunk Run a function that does something with the value from the current loop position of each thread For instance, say I had a bunch of objects in a game loop (as I am developing a game and was thinking about the possibility of multiple threads) and had to do something with each of them every frame, would the above be trivial to pull off? Looking at IEnumerable it seems it only keeps track of the current position, so I'm not sure I could use the normal generic collections to break the enumeration into "chunks". Sorry about this question. I used bullets above instead of pseudo-code because I don't even know enough to write pseudo-code off the top of my head. My .NET knowledge has been purely simple business stuff and I'm new to delegates and threads, etc. I mainly want to know if the above approach is good for pursuing, and if delegates/lambdas don't have to be worried about when it comes to their parallelization.

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  • .Net lambda expression-- where did this parameter come from?

    - by larryq
    I'm a lambda newbie, so if I'm missing vital information in my description please tell me. I'll keep the example as simple as possible. I'm going over someone else's code and they have one class inheriting from another. Here's the derived class first, along with the lambda expression I'm having trouble understanding: class SampleViewModel : ViewModelBase { private ICustomerStorage storage = ModelFactory<ICustomerStorage>.Create(); public ICustomer CurrentCustomer { get { return (ICustomer)GetValue(CurrentCustomerProperty); } set { SetValue(CurrentCustomerProperty, value); } } private int quantitySaved; public int QuantitySaved { get { return quantitySaved; } set { if (quantitySaved != value) { quantitySaved = value; NotifyPropertyChanged(p => QuantitySaved); //where does 'p' come from? } } } public static readonly DependencyProperty CurrentCustomerProperty; static SampleViewModel() { CurrentCustomerProperty = DependencyProperty.Register("CurrentCustomer", typeof(ICustomer), typeof(SampleViewModel), new UIPropertyMetadata(ModelFactory<ICustomer>.Create())); } //more method definitions follow.. Note the call to NotifyPropertyChanged(p => QuantitySaved) bit above. I don't understand where the "p" is coming from. Here's the base class: public abstract class ViewModelBase : DependencyObject, INotifyPropertyChanged, IXtremeMvvmViewModel { public event PropertyChangedEventHandler PropertyChanged; protected virtual void NotifyPropertyChanged<T>(Expression<Func<ViewModelBase, T>> property) { MvvmHelper.NotifyPropertyChanged(property, PropertyChanged); } } There's a lot in there that's not germane to the question I'm sure, but I wanted to err on the side of inclusiveness. The problem is, I don't understand where the 'p' parameter is coming from, and how the compiler knows to (evidently?) fill in a type value of ViewModelBase from thin air? For fun I changed the code from 'p' to 'this', since SampleViewModel inherits from ViewModelBase, but I was met with a series of compiler errors, the first one of which statedInvalid expression term '=>' This confused me a bit since I thought that would work. Can anyone explain what's happening here?

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  • Copy vector of values to vector of pairs in one line

    - by Kirill V. Lyadvinsky
    I have the following types: struct X { int x; X( int val ) : x(val) {} }; struct X2 { int x2; X2() : x2() {} }; typedef std::pair<X, X2> pair_t; typedef std::vector<pair_t> pairs_vec_t; typedef std::vector<X> X_vec_t; I need to initialize instance of pairs_vec_t with values from X_vec_t. I use the following code and it works as expected: int main() { pairs_vec_t ps; X_vec_t xs; // this is not empty in the production code ps.reserve( xs.size() ); { // I want to change this block to one line code. struct get_pair { pair_t operator()( const X& value ) { return std::make_pair( value, X2() ); } }; std::transform( xs.begin(), xs.end(), back_inserter(ps), get_pair() ); } return 0; } What I'm trying to do is to reduce my copying block to one line with using boost::bind. This code is not working: for_each( xs.begin(), xs.end(), boost::bind( &pairs_vec_t::push_back, ps, boost::bind( &std::make_pair, _1, X2() ) ) ); I know why it is not working, but I want to know how to make it working without declaring extra functions and structs?

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  • Linker problem linking boost in Visual Studio 2008

    - by Tobias Langner
    Hi, I have a rather obscure linking problem in Visual Studio 2008. The linker error message is: "LNK1104: cannot open file 'boost_thread-vc90-mt-gd-1_38.lib'". All pathes and dependencies are set. What I noticed though is that Visual Studio misses boost_thread-vc90-mt-gd-1_38.lib and not libboost_thread-vc90-mt-gd-1_38.lib (notice the lib at the beginning of the file name). I added the .lib as libboost_thread-vc90-mt-gd-1_38.lib to the project and it appears as libboost_thread-vc90-mt-gd-1_38.lib in the command line. Why does Visual Studio the beginning of the file name?

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  • boost ublas: rotate 2d vector

    - by AndreasT
    Erm. I hope I am seriously overlooking something. I want to rotate a 2d vector (kartesian) v by a certain angle phi. I can't find a function that generates the appropriate matrix or just performs that function. I know how to do this by hand. I am looking for a ublas utility "something" that does this for me.

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