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  • How to boost system sound output?

    - by infant programmer
    When I use Earphones, I feel that my system output is very low, I have set all the volume output to maximum in "control panel\Sounds and Audio devices", but still not satisfactory. May be my earphones output proportionality is lower. No problem with sub-woofer, I think its because of the amplifier. Is there any software to boost up system volume output to compensate ?

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  • Rewrite rules for Drupal Boost with Lighttpd

    - by bsdjunkie
    I have been given the super task of preparing a web site to get hammered.... Or site is drupal based, I have found what could be my answer in the form of Boost. But I can't for the life of me find any information on the Lighttpd rewrite rules to make it function. All suggestion welcome! Thanks

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  • Unable to create unmanaged object using new keyword in managed C++

    - by chair79
    Hi all, I've created a class with a boost::unordered_map as a member, Linkage.h #ifndef LINKAGE_H #define LINKAGE_H #include <boost/unordered_map.hpp> class Linkage { private: boost::unordered_map<int, int> m_IOMap; public: .... }; Linkage.cpp #include "stdafx.h" ... // methods and in the managed side of C++, I try to create the pointer of the obj: private: System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e) { Linkage* m_pLink = new Linkage(); ..... } However this produces errors: Error 4 error LNK2005: "private: static unsigned int const boost::detail::type_with_alignment_imp<4>::found" (?found@?$type_with_alignment_imp@$03@detail@boost@@$$Q0IB) already defined in Proj_Test.obj Linkage.obj ..... Error 7 fatal error LNK1169: one or more multiply defined symbols found Could anyone explain to me pls? Thanks.

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  • Function Composition in C++

    - by Channel72
    There are a lot of impressive Boost libraries such as Boost.Lambda or Boost.Phoenix which go a long way towards making C++ into a truly functional language. But is there a straightforward way to create a composite function from any 2 or more arbitrary functions or functors? If I have: int f(int x) and int g(int x), I want to do something like f . g which would statically generate a new function object equivalent to f(g(x)). This seems to be possible through various techniques, such as those discussed here. Certainly, you can chain calls to boost::lambda::bind to create a composite functor. But is there anything in Boost which easily allows you to take any 2 or more functions or function objects and combine them to create a single composite functor, similar to how you would do it in a language like Haskell?

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  • getting names subgroups

    - by Abruzzo Forte e Gentile
    Hi All I am working with the new version of boost 1.42 and I want to use regex with named sub groups. Below an example. std::string line("match this here FIELD=VALUE in the middle"); boost::regex rgx("FIELD=(?\\w+)", boost::regex::perl ); boost::smatch thisMatch; boost::regex_searh( line, thisMatch, rgx ); Do you know how to get the content of the match ? The traditional way is std::string result( mtch["VAL"].first, mtch["VAL"].second ); but i don't want to use this way. I want to use the name of the subgroups as usual in Perl and in regex in general. I tried this, but it didn't work. std::string result( mtch["VAL"].first, mtch["VAL"].second ); Do you know how to get the value using the name of the subgroup? Thanks AFG

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  • typedef declaration syntax

    - by mt_serg
    Some days ago I looked at boost sources and found interesting typedef. There is a code from "boost\detail\none_t.hpp": namespace boost { namespace detail { struct none_helper{}; typedef int none_helper::*none_t ; } // namespace detail } // namespace boost I didn't see syntax like that earlier and can't explain the sense of that. This typedef introduces name "none_t" as pointer to int in boost::detail namespace. What the syntax is? And what difference between "typedef int none_helper::*none_t" and for example "typedef int *none_t" ?

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  • SOLR - Boost function (bf) to increase score of documents whose date is closest to NOW

    - by Mechanic
    Hi all, I have a solr instance containing documents which have a 'startTime' field ranging from last month to a year from now. I'd like to add a boost query/function to boost the scores of documents whose startTime field is close to the current time. So far I have seen a lot of examples which use rord to add boosts to documents whom are newer but I have never seen an example of something like this. Can anyone tell me how to do it please? Thanks

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  • To find a determinate of Matrix using Boost library in c++

    - by user314097
    Hi, I' am required to convert a MATLAB function into C++, and this requires me to find determinate of a matrix. I was told that use of BOOST library would make my job easier. I went through the documentation of BOOST Library, but couldn't find much info about the same. If anyone could give a template for the above operation, It would be of lot of help and would be greatly appreciated. Thanks Regards

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  • C++ Multithreading on Unix

    - by Roger
    I have two related questions: 1) Are there any good books for multithreading in C++, especially now that C++11 contains multithreading in the standard library? 2) I have the Wrox Programming on Unix book (1000 pages fat red one) and within it, it uses the Unix Thread class. How does this code relate to boost and the C++11 multithreading libraries? Is it better/worse/just specific to Unix etc? Is the performance the same?

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  • Find version of development library from command line?

    - by mathematician1975
    I installed the c++ boost development libraries using Ubuntu software centre. The problem is that it was quite a long time ago and I cannot remember where they are installed nor what version they were. Is there anything I can do from the command line that will tell me what version(s) I have installed on my system?? I know I can do things like gcc -v to get version of an application but is there a similar thing available for libraries? I am using ubuntu 12.04

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  • undefined reference to `main' collect2: ld returned 1 exit status

    - by sobingt
    I am working on this QT project and i am making test cases for my project. Here is a small test case #include <QApplication> #include <QPalette> #include <QPixmap> #include <QSplashScreen> #include <qthread.h> #define BOOST_TEST_MAIN #include <boost/test/unit_test.hpp> #include <boost/make_shared.hpp> # include <boost/thread.hpp> #include "MainWindow.h" namespace { const std::string dbname = "Project.db"; struct SongFixture { SongFixture(const std::string &fixturePath) { // Create the Master file Master::creator(); // Create/open file std::pair<int, SQLiteDbPtr> result = open( dbname, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0); if (result.first != SQLITE_OK) { throw SQLiteError(result.first, sqlite3_errmsg(result.second.get())); } SQLiteDbPtr &spDb = result.second; // Execute all the SQL from the fixture file execSQLFromFile(spDb, fixturePath); } }; std::auto_ptr<SongFixture> pf; } class I : public QThread { public: static void sleep(unsigned long secs) { QThread::sleep(secs); } }; void free_test_function() { BOOST_CHECK(true ); } test_suite* init_unit_test_suite(int argc, char *argv[]) { // Create a fixture for the peer: // Manage fixture creation manually instead of using // BOOST_FIXTURE_TEST_CASE because the fixture depends on runtime args. std::ostringstream fixturePathSS; fixturePathSS << PROJECT_DIR << "/test/songs_fixture.sql"; std::string fixturePath = fixturePathSS.str(); pf.reset(new SongFixture(fixturePath)); QApplication app(argc, argv); MainWindow window("artists"); window.show(); framework::master_test_suite().add( BOOST_TEST_CASE( &free_test_function )); return app.exec(); } Well i am getting any error /usr/lib/gcc/x86_64-linux-gnu/4.6.1/../../../x86_64-linux-gnu/crt1.o: In function _start': (.text+0x20): undefined reference tomain' collect2: ld returned 1 exit status pls help me you have a lead..thankz I tired adding #define BOOST_TEST_MAIN then i get ../test/UI/main.cpp: In function ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’: ../test/UI/main.cpp:75:31: error: redefinition of ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’ /usr/local/include/boost/test/unit_test_suite.hpp:223:1: error: ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’ previously defined here Well the program is working in Windows but in Linux the above mention problem is observed

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  • why BOOST_FOREACH cannot handle const boost::ptr_map?

    - by psaghelyi
    void main() { typedef boost::ptr_map<int, char> MyMap; MyMap mymap; mymap[1] = 'a'; mymap[2] = 'b'; mymap[3] = 'c'; BOOST_FOREACH(MyMap::value_type value, mymap) { std::cout << value.first << " " << value.second << std::endl; } MyMap const & const_mymap = mymap; BOOST_FOREACH(MyMap::value_type value, const_mymap) { std::cout << value.first << " " << value.second << std::endl; } } The following error message comes from GCC at the second BOOST_FOREACH error: conversion from 'boost::ptr_container_detail::ref_pair<int, const char* const>' to non-scalar type 'boost::ptr_container_detail::ref_pair<int, char* const>' requested I reckon that this is the weakness of the pointer container's ref_pair...

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  • Class member functions instantiated by traits

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched Stack Overflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate non-virtual member functions? The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state information was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (VC++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice? UPDATE: Here's another try at explaining it. I want the user to be able to fill out an order (manifest) for a custom optimizer, something like ordering off of a Chinese menu - one from column A, one from column B, etc.. Waiter, from column A (updaters), I'll have the BFGS update with Cholesky-decompositon sauce. From column B (line-searchers), I'll have the cubic interpolation line-search with an eta of 0.4 and a rho of 1e-4, please. Etc... UPDATE: Okay, okay. Here's the playing-around that I've done. I offer it reluctantly, because I suspect it's a completely wrong-headed approach. It runs okay under vc++ 2008. #include <boost/utility.hpp> #include <boost/type_traits/integral_constant.hpp> namespace dj { struct CBFGS { void bar() {printf("CBFGS::bar %d\n", data);} CBFGS(): data(1234){} int data; }; template<class T> struct is_CBFGS: boost::false_type{}; template<> struct is_CBFGS<CBFGS>: boost::true_type{}; struct LMQN {LMQN(): data(54.321){} void bar() {printf("LMQN::bar %lf\n", data);} double data; }; template<class T> struct is_LMQN: boost::false_type{}; template<> struct is_LMQN<LMQN> : boost::true_type{}; struct default_optimizer_traits { typedef CBFGS update_type; }; template<class traits> class Optimizer; template<class traits> void foo(typename boost::enable_if<is_LMQN<typename traits::update_type>, Optimizer<traits> >::type& self) { printf(" LMQN %lf\n", self.data); } template<class traits> void foo(typename boost::enable_if<is_CBFGS<typename traits::update_type>, Optimizer<traits> >::type& self) { printf("CBFGS %d\n", self.data); } template<class traits = default_optimizer_traits> class Optimizer{ friend typename traits::update_type; //friend void dj::foo<traits>(typename Optimizer<traits> & self); // How? public: //void foo(void); // How??? void foo() { dj::foo<traits>(*this); } void bar() { data.bar(); } //protected: // How? typedef typename traits::update_type update_type; update_type data; }; } // namespace dj int main_() { dj::Optimizer<> opt; opt.foo(); opt.bar(); std::getchar(); return 0; }

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  • Boost.MultiIndex: How to make an effective set intersection?

    - by Arman
    Hello, assume that we have a data1 and data2. How can I intersect them with std::set_intersect()? struct pID { int ID; unsigned int IDf;// postition in the file pID(int id,const unsigned int idf):ID(id),IDf(idf){} bool operator<(const pID& p)const { return ID<p.ID;} }; struct ID{}; struct IDf{}; typedef multi_index_container< pID, indexed_by< ordered_unique< tag<IDf>, BOOST_MULTI_INDEX_MEMBER(pID,unsigned int,IDf)>, ordered_non_unique< tag<ID>,BOOST_MULTI_INDEX_MEMBER(pID,int,ID)> > > pID_set; ID_set data1, data2; Load(data1); Load(data2); pID_set::index<ID>::type& L1_ID_index=L1.data.get<ID>(); pID_set::index<ID>::type& L2_ID_index=L2.data.get<ID>(); // How do I use set_intersect? Kind regards, Arman.

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  • How to write rule for ICU genrb and pkgdata for boost-build?

    - by sandy
    jamroot.jam rule genrb ( sources + : requirements * ) # create *.res files in binary directory { local result ; for local r in $(sources) { res $(r:B) : $(r) ; } } res.jam type.register RES : res ; type.register TXT : txt ; generators.register-standard res.resource : TXT : RES ; actions resource { $(icu_home)\bin64\genrb "-d$(<:D)" "$()" } I need to run pkgdata with parameters: pkgdata [-options] [-] [packageFile] packageFile is a text file containing the list of res-files to package.

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  • Why can't I extract a C++ type from a Python type using boost::python::extractor?

    - by Robin
    I've wrapped a C++ class using Py++ and everything is working great in Python. I can instantiate the c++ class, call methods, etc. I'm now trying to embed some Python into a C++ application. This is also working fine for the most-part. I can call functions on a Python module, get return values, etc. The python code I'm calling returns one of the classes that I wrapped: import _myextension as myext def run_script(arg): my_cpp_class = myext.MyClass() return my_cpp_class I'm calling this function from C++ like this: // ... excluding error checking, ref counting, etc. for brevity ... PyObject *pModule, *pFunc, *pArgs, *pReturnValue; Py_Initialize(); pModule = PyImport_Import(PyString_FromString("cpp_interface")); pFunc = PyObject_GetAttrString(pModule, "run_script"); pArgs = PyTuple_New(1); PyTuple_SetItem(pArgs, 0, PyString_FromString("an arg")); pReturnValue = PyObject_CallObject(pFunc, pArgs); bp::extract< MyClass& > extractor(pReturnValue); // PROBLEM IS HERE if (extractor.check()) { // This check is always false MyClass& cls = extractor(); } The problem is the extractor never actually extracts/converts the PyObject* to MyClass (i.e. extractor.check() is always false). According to the docs this is the correct way to extract a wrapped C++ class. I've tried returning basic data types (ints/floats/dicts) from the Python function and all of them are extracted properly. Is there something I'm missing? Is there another way to get the data and cast to MyClass?

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  • [boost::filesystem] performance: is it better to read all files once, or use b::fs functions over an

    - by rubenvb
    I'm conflicted between a "read once, use memory+pointers to files" and a "read when necessary" approach. The latter is of course much easier (no additional classes needed to store the whole dir structure), but IMO it is slower? A little clarification: I'm writing a simple build system, that read a project file, checks if all files are present, and runs some compile steps. The file tree is static, so the first option doesn't need to be very dynamic and only needs to be built once every time the program is run. Thanks

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  • fatal error LNK1104: cannot open file 'libboost_system-vc90-mt-gd-1_43.lib'

    - by Poni
    Made a new project, added main.cpp and wrote the code at this URL: http://www.boost.org/doc/libs/1_43_0/doc/html/boost_asio/example/echo/async_tcp_echo_server.cpp Also, added the appropriate include path. What's next?!?!! It seems like a darn mystery to build a boost code! Been digging on it for more than 10 hours. Can anyone give a straightforward answer on how to build the boost library from the code under windows, VC9? God bless you all.

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  • Class member functions instantiated by traits [policies, actually]

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched Stack Overflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate member functions? [Update: I used the wrong term here. It should be "policies" rather than "traits." Traits describe existing classes. Policies prescribe synthetic classes.] The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state information was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (VC++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice? UPDATE: Here's another try at explaining it. I want the user to be able to fill out an order (manifest) for a custom optimizer, something like ordering off of a Chinese menu - one from column A, one from column B, etc.. Waiter, from column A (updaters), I'll have the BFGS update with Cholesky-decompositon sauce. From column B (line-searchers), I'll have the cubic interpolation line-search with an eta of 0.4 and a rho of 1e-4, please. Etc... UPDATE: Okay, okay. Here's the playing-around that I've done. I offer it reluctantly, because I suspect it's a completely wrong-headed approach. It runs okay under vc++ 2008. #include <boost/utility.hpp> #include <boost/type_traits/integral_constant.hpp> namespace dj { struct CBFGS { void bar() {printf("CBFGS::bar %d\n", data);} CBFGS(): data(1234){} int data; }; template<class T> struct is_CBFGS: boost::false_type{}; template<> struct is_CBFGS<CBFGS>: boost::true_type{}; struct LMQN {LMQN(): data(54.321){} void bar() {printf("LMQN::bar %lf\n", data);} double data; }; template<class T> struct is_LMQN: boost::false_type{}; template<> struct is_LMQN<LMQN> : boost::true_type{}; // "Order form" struct default_optimizer_traits { typedef CBFGS update_type; // Selection from column A - updaters }; template<class traits> class Optimizer; template<class traits> void foo(typename boost::enable_if<is_LMQN<typename traits::update_type>, Optimizer<traits> >::type& self) { printf(" LMQN %lf\n", self.data); } template<class traits> void foo(typename boost::enable_if<is_CBFGS<typename traits::update_type>, Optimizer<traits> >::type& self) { printf("CBFGS %d\n", self.data); } template<class traits = default_optimizer_traits> class Optimizer{ friend typename traits::update_type; //friend void dj::foo<traits>(typename Optimizer<traits> & self); // How? public: //void foo(void); // How??? void foo() { dj::foo<traits>(*this); } void bar() { data.bar(); } //protected: // How? typedef typename traits::update_type update_type; update_type data; }; } // namespace dj int main() { dj::Optimizer<> opt; opt.foo(); opt.bar(); std::getchar(); return 0; }

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  • Libtool versioning of a library that depends on other libraries.

    - by Artyom
    Hello, I have a framework that uses Boost and CgiCC in the core application and in its interface. How should I version the library binary interface (a.k.a. libtool -version-info)? I have no problems tracking the changes in library itself when I make various changes. As it is clear for me how should I version. But... Both Boost and CgiCC libraries do not provide any backward compatible API/ABI and my library may be linked with quite arbitrary versions Boost and CgiCC so I can't provide any promise about the interfaces, so I can't really specify -version-info because even the same library compiled against different versions of Boost and CgiCC would not be compatible. So... What should I do? How should I version library? I know that I should not depend on Boost and CgiCC interfaces in first place, but this is what I get so far for existing stable version. This issue is addressed in next major release but I still have and want to maintain current release as it is very valuable.

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  • Recommendations for a C++ polymorphic, seekable, binary I/O interface

    - by Trevor Robinson
    I've been using std::istream and ostream as a polymorphic interface for random-access binary I/O in C++, but it seems suboptimal in numerous ways: 64-bit seeks are non-portable and error-prone due to streampos/streamoff limitations; currently using boost/iostreams/positioning.hpp as a workaround, but it requires vigilance Missing operations such as truncating or extending a file (ala POSIX ftruncate) Inconsistency between concrete implementations; e.g. stringstream has independent get/put positions whereas filestream does not Inconsistency between platform implementations; e.g. behavior of seeking pass the end of a file or usage of failbit/badbit on errors Don't need all the formatting facilities of stream or possibly even the buffering of streambuf streambuf error reporting (i.e. exceptions vs. returning an error indicator) is supposedly implementation-dependent in practice I like the simplified interface provided by the Boost.Iostreams Device concept, but it's provided as function templates rather than a polymorphic class. (There is a device class, but it's not polymorphic and is just an implementation helper class not necessarily used by the supplied device implementations.) I'm primarily using large disk files, but I really want polymorphism so I can easily substitute alternate implementations (e.g. use stringstream instead of fstream for unit tests) without all the complexity and compile-time coupling of deep template instantiation. Does anyone have any recommendations of a standard approach to this? It seems like a common situation, so I don't want to invent my own interfaces unnecessarily. As an example, something like java.nio.FileChannel seems ideal. My best solution so far is to put a thin polymorphic layer on top of Boost.Iostreams devices. For example: class my_istream { public: virtual std::streampos seek(stream_offset off, std::ios_base::seekdir way) = 0; virtual std::streamsize read(char* s, std::streamsize n) = 0; virtual void close() = 0; }; template <class T> class boost_istream : public my_istream { public: boost_istream(const T& device) : m_device(device) { } virtual std::streampos seek(stream_offset off, std::ios_base::seekdir way) { return boost::iostreams::seek(m_device, off, way); } virtual std::streamsize read(char* s, std::streamsize n) { return boost::iostreams::read(m_device, s, n); } virtual void close() { boost::iostreams::close(m_device); } private: T m_device; };

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