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  • Specialization of template after instantiation?

    - by Onur Cobanoglu
    Hi, My full code is too long, but here is a snippet that will reflect the essence of my problem: class BPCFGParser { public: ... ... class Edge { ... ... }; class ActiveEquivClass { ... ... }; class PassiveEquivClass { ... ... }; struct EqActiveEquivClass { ... ... }; struct EqPassiveEquivClass { ... ... }; unordered_map<ActiveEquivClass, Edge *, hash<ActiveEquivClass>, EqActiveEquivClass> discovered_active_edges; unordered_map<PassiveEquivClass, Edge *, hash<PassiveEquivClass>, EqPassiveEquivClass> discovered_passive_edges; }; namespace std { template <> class hash<BPCFGParser::ActiveEquivClass> { public: size_t operator()(const BPCFGParser::ActiveEquivClass & aec) const { } }; template <> class hash<BPCFGParser::PassiveEquivClass> { public: size_t operator()(const BPCFGParser::PassiveEquivClass & pec) const { } }; } When I compile this code, I get the following errors: In file included from BPCFGParser.cpp:3, from experiments.cpp:2: BPCFGParser.h:408: error: specialization of ‘std::hash<BPCFGParser::ActiveEquivClass>’ after instantiation BPCFGParser.h:408: error: redefinition of ‘class std::hash<BPCFGParser::ActiveEquivClass>’ /usr/include/c++/4.3/tr1_impl/functional_hash.h:44: error: previous definition of ‘class std::hash<BPCFGParser::ActiveEquivClass>’ BPCFGParser.h:445: error: specialization of ‘std::hash<BPCFGParser::PassiveEquivClass>’ after instantiation BPCFGParser.h:445: error: redefinition of ‘class std::hash<BPCFGParser::PassiveEquivClass>’ /usr/include/c++/4.3/tr1_impl/functional_hash.h:44: error: previous definition of ‘class std::hash<BPCFGParser::PassiveEquivClass>’ Now I have to specialize std::hash for these classes (because standard std::hash definition does not include user defined types). When I move these template specializations before the definition of class BPCFGParser, I get a variety of errors for a variety of different things tried, and somewhere (http://www.parashift.com/c++-faq-lite/misc-technical-issues.html) I read that: Whenever you use a class as a template parameter, the declaration of that class must be complete and not simply forward declared. So I'm stuck. I cannot specialize the templates after BPCFGParser definition, I cannot specialize them before BPCFGParser definition, how may I get this working? Thanks in advance, Onur

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  • Error with Phoenix placeholder _val in Boost.Spirit.Lex :(

    - by GooRoo
    Hello, everybody. I'm newbie in Boost.Spirit.Lex. Some strange error appears every time I try to use lex::_val in semantics actions in my simple lexer: #ifndef _TOKENS_H_ #define _TOKENS_H_ #include <iostream> #include <string> #include <boost/spirit/include/lex_lexertl.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_statement.hpp> #include <boost/spirit/include/phoenix_container.hpp> namespace lex = boost::spirit::lex; namespace phx = boost::phoenix; enum tokenids { ID_IDENTIFICATOR = 1, ID_CONSTANT, ID_OPERATION, ID_BRACKET, ID_WHITESPACES }; template <typename Lexer> struct mega_tokens : lex::lexer<Lexer> { mega_tokens() : identifier(L"[a-zA-Z_][a-zA-Z0-9_]*", ID_IDENTIFICATOR) , constant (L"[0-9]+(\\.[0-9]+)?", ID_CONSTANT ) , operation (L"[\\+\\-\\*/]", ID_OPERATION ) , bracket (L"[\\(\\)\\[\\]]", ID_BRACKET ) { using lex::_tokenid; using lex::_val; using phx::val; this->self = operation [ std::wcout << val(L'<') << _tokenid // << val(L':') << lex::_val << val(L'>') ] | identifier [ std::wcout << val(L'<') << _tokenid << val(L':') << _val << val(L'>') ] | constant [ std::wcout << val(L'<') << _tokenid // << val(L':') << _val << val(L'>') ] | bracket [ std::wcout << phx::val(lex::_val) << val(L'<') << _tokenid // << val(L':') << lex::_val << val(L'>') ] ; } lex::token_def<wchar_t, wchar_t> operation; lex::token_def<std::wstring, wchar_t> identifier; lex::token_def<double, wchar_t> constant; lex::token_def<wchar_t, wchar_t> bracket; }; #endif // _TOKENS_H_ and #include <cstdlib> #include <iostream> #include <locale> #include <boost/spirit/include/lex_lexertl.hpp> #include "tokens.h" int main() { setlocale(LC_ALL, "Russian"); namespace lex = boost::spirit::lex; typedef std::wstring::iterator base_iterator; typedef lex::lexertl::token < base_iterator, boost::mpl::vector<wchar_t, std::wstring, double, wchar_t>, boost::mpl::true_ > token_type; typedef lex::lexertl::actor_lexer<token_type> lexer_type; typedef mega_tokens<lexer_type>::iterator_type iterator_type; mega_tokens<lexer_type> mega_lexer; std::wstring str = L"alfa+x1*(2.836-x2[i])"; base_iterator first = str.begin(); bool r = lex::tokenize(first, str.end(), mega_lexer); if (r) { std::wcout << L"Success" << std::endl; } else { std::wstring rest(first, str.end()); std::wcerr << L"Lexical analysis failed\n" << L"stopped at: \"" << rest << L"\"\n"; } return EXIT_SUCCESS; } This code causes an error in Boost header 'boost/spirit/home/lex/argument.hpp' on line 167 while compiling: return: can't convert 'const boost::variant' to 'boost::variant &' When I don't use lex::_val program compiles with no errors. Obviously, I use _val in wrong way, but I do not know how to do this correctly. Help, please! :) P.S. And sorry for my terrible English…

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  • Read and write struct in C

    - by Sergey
    I have a struct: typedef struct student { char fname[30]; char sname[30]; char tname[30]; Faculty fac; int course; char group[10]; int room; int bad; } Student; I read it from the file: Database * dbOpen(char *fname) { FILE *fp = fopen(fname, "rb"); List *lst, *temp; Student *std; Database *db = malloc(sizeof(*db)); if (!fp) return NULL; FileNameS = fname; std = malloc(sizeof(*std)); if (!fread(std, sizeof(*std), 1, fp)) { db->head = db->tail = NULL; return db; } lst = malloc(sizeof(*lst)); lst->s = std; lst->prev = NULL; db->head = lst; while (!feof(fp)) { fread(std, sizeof(*std), 1, fp); temp = malloc(sizeof(*temp)); temp->s = std; temp->prev = lst; lst->next = temp; lst = temp; } lst->next = NULL; db->tail = lst; fclose(fp); return db; } And I have a problem... At the last record i have a such file pointer: `fp 0x10311448 {_ptr=0x00344b90 "???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? _ _iobuf * ` And i read last record 2 times... Save file code: void * dbClose(Database *db) { FILE *fp = fopen(FileNameS, "w+b"); List *lst, *temp; lst = db->head; while(lst != NULL) { fwrite(lst->s, sizeof(*(lst->s)), 1, fp); temp = lst; lst = lst->next; free(temp); } free(db); fclose(fp); }

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  • Vim + OmniCppComplete: Completing on Class Members which are STL containers

    - by Robert S. Barnes
    Completion on class members which are STL containers is failing. Completion on local objects which are STL containers works fine. For example, given the following files: // foo.h #include <string> class foo { public: void set_str(const std::string &); std::string get_str_reverse( void ); private: std::string str; }; // foo.cpp #include "foo.h" using std::string; string foo::get_str_reverse ( void ) { string temp; temp.assign(str); reverse(temp.begin(), temp.end()); return temp; } /* ----- end of method foo::get_str ----- */ void foo::set_str ( const string &s ) { str.assign(s); } /* ----- end of method foo::set_str ----- */ I've generated the tags for these two files using: ctags -R --c++-kinds=+pl --fields=+iaS --extra=+q . When I type temp. in the cpp I get a list of string member functions as expected. But if I type str. omnicppcomplete spits out "Pattern Not Found". I've noticed that the temp. completion only works if I have the using std::string; declaration. How do I get completion to work on my class members which are STL containers? Edit I found that completion on members which are STL containers works if I make the follow modifications to the header: // foo.h #include <string> using std::string; class foo { public: void set_str(const string &); string get_str_reverse( void ); private: string str; }; Basically, if I add using std::string; and then remove the std:: name space qualifier from the string str; member and regenerate the tags file then OmniCppComplete is able to do completion on str.. It doesn't seem to matter whether or not I have let OmniCpp_DefaultNamespaces = ["std", "_GLIBCXX_STD"] set in the .vimrc. The problem is that putting using declarations in header files seems like a big no-no, so I'm back to square one.

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  • Help with these warnings. [inheritance].

    - by sil3nt
    Hello there. I have a set of code, which mimics a basic library cataloging system. There is a base class named items, in which the the general id,title and year variables are defined and 3 other derived classes (DVD,Book and CD). Base [Items] Derived [DVD,Book,CD]. The programs runs, however I get the following warnings, I'm not sure how to fix these. "C:\Program Files\gcc\bin/g++" -Os -mconsole -g -Wall -Wshadow -fno-common mainA4.cpp -o mainA4.exe In file included from mainA4.cpp:5: a4.h: In constructor `DVD::DVD(int, std::string, int, std::string)': a4.h:28: warning: `DVD::director' will be initialized after a4.h:32: warning: base `Items' a4.h:32: warning: when initialized here a4.h: In constructor `Book::Book(int, std::string, int, std::string, int)': a4.h:48: warning: `Book::numPages' will be initialized after a4.h:52: warning: base `Items' a4.h:52: warning: when initialized here a4.h: In constructor `CD::CD(int, std::string, int, std::string, int)': a4.h:66: warning: `CD::numSongs' will be initialized after a4.h:70: warning: base `Items' a4.h:70: warning: when initialized here Exit code: 0

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  • Removing a character from a string

    - by Prasanth Madhavan
    i have a string. I want to delete the last character of the string if it is a space. i tried the following code, str.erase(remove_if(str.begin(), str.end(), isspace), str.end()); but my g++ compiler gives me an error saying: error: no matching function for call to ‘remove_if(__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, <unresolved overloaded function type>)’ please help.

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  • Is there a standard Cyclic Iterator in C++

    - by Hippicoder
    Based on the following question: Check if one string is a rotation of other string I was thinking of making a cyclic iterator type that takes a range, and would be able to solve the above problem like so: std::string s1 = "abc" ; std::string s2 = "bca" ; std::size_t n = 2; // number of cycles cyclic_iterator it(s2.begin(),s2.end(),n); cyclic_iterator end; if (std::search(it, end, s1.begin(),s1.end()) != end) { std::cout << "s1 is a rotation of s2" << std::endl; } My question, Is there already something like this available? I've check Boost and STL doesn't have one. I've got a simple hand-written one but would rather use an already made/tested implementation.

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  • OpenGL textures trigger error 1281 and strange background behavior

    - by user3714670
    I am using SOIL to apply textures to VBOs, without textures i could change the background and display black (default color) vbos easily, but now with textures, openGL is giving an error 1281, the background is black and some textures are not applied. There must be something i didn't understand about applying/loading the textures. BUt the texture IS applied (nothing else is working though), the error is applied when i try to use the shader program however i checked the compilation of these and no problems were written. Here is the code i use to load textures, once loaded it is kept in memory, it mostly comes from the example of SOIL : texture = SOIL_load_OGL_single_cubemap( filename, SOIL_DDS_CUBEMAP_FACE_ORDER, SOIL_LOAD_AUTO, SOIL_CREATE_NEW_ID, SOIL_FLAG_POWER_OF_TWO | SOIL_FLAG_MIPMAPS | SOIL_FLAG_DDS_LOAD_DIRECT ); if( texture > 0 ) { glEnable( GL_TEXTURE_CUBE_MAP ); glEnable( GL_TEXTURE_GEN_S ); glEnable( GL_TEXTURE_GEN_T ); glEnable( GL_TEXTURE_GEN_R ); glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP ); glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP ); glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP ); glBindTexture( GL_TEXTURE_CUBE_MAP, texture ); std::cout << "the loaded single cube map ID was " << texture << std::endl; } else { std::cout << "Attempting to load as a HDR texture" << std::endl; texture = SOIL_load_OGL_HDR_texture( filename, SOIL_HDR_RGBdivA2, 0, SOIL_CREATE_NEW_ID, SOIL_FLAG_POWER_OF_TWO | SOIL_FLAG_MIPMAPS ); if( texture < 1 ) { std::cout << "Attempting to load as a simple 2D texture" << std::endl; texture = SOIL_load_OGL_texture( filename, SOIL_LOAD_AUTO, SOIL_CREATE_NEW_ID, SOIL_FLAG_POWER_OF_TWO | SOIL_FLAG_MIPMAPS | SOIL_FLAG_DDS_LOAD_DIRECT ); } if( texture > 0 ) { // enable texturing glEnable( GL_TEXTURE_2D ); // bind an OpenGL texture ID glBindTexture( GL_TEXTURE_2D, texture ); std::cout << "the loaded texture ID was " << texture << std::endl; } else { glDisable( GL_TEXTURE_2D ); std::cout << "Texture loading failed: '" << SOIL_last_result() << "'" << std::endl; } } and how i apply it when drawing : GLuint TextureID = glGetUniformLocation(shaderProgram, "myTextureSampler"); if(!TextureID) cout << "TextureID not found ..." << endl; // glEnableVertexAttribArray(TextureID); glActiveTexture(GL_TEXTURE0); if(SFML) sf::Texture::bind(sfml_texture); else { glBindTexture (GL_TEXTURE_2D, texture); // glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 1024, 768, 0, GL_RGB, GL_UNSIGNED_BYTE, &texture); } glUniform1i(TextureID, 0); I am not sure that SOIL is adapted to my program as i want something as simple as possible (i used sfml's texture object which was the best but i can't anymore), but if i can get it to work it would be great. EDIT : After narrowing the code implied by the error, here is the code that provokes it, it is called between texture loading and bos drawing : glEnableClientState(GL_VERTEX_ARRAY); //this gives the error : glUseProgram(this->shaderProgram); if (!shaderLoaded) { std::cout << "Loading default shaders" << std::endl; if(textured) loadShaderProgramm(texture_vertexSource, texture_fragmentSource); else loadShaderProgramm(default_vertexSource,default_fragmentSource); } glm::mat4 Projection = camera->getPerspective(); glm::mat4 View = camera->getView(); glm::mat4 Model = glm::mat4(1.0f); Model[0][0] *= scale_x; Model[1][1] *= scale_y; Model[2][2] *= scale_z; glm::vec3 translate_vec(this->x,this->y,this->z); glm::mat4 object_transform = glm::translate(glm::mat4(1.0f),translate_vec); glm::quat rotation = QAccumulative.getQuat(); glm::mat4 matrix_rotation = glm::mat4_cast(rotation); object_transform *= matrix_rotation; Model *= object_transform; glm::mat4 MVP = Projection * View * Model; GLuint ModelID = glGetUniformLocation(this->shaderProgram, "M"); if(ModelID ==-1) cout << "ModelID not found ..." << endl; GLuint MatrixID = glGetUniformLocation(this->shaderProgram, "MVP"); if(MatrixID ==-1) cout << "MatrixID not found ..." << endl; GLuint ViewID = glGetUniformLocation(this->shaderProgram, "V"); if(ViewID ==-1) cout << "ViewID not found ..." << endl; glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &MVP[0][0]); glUniformMatrix4fv(ModelID, 1, GL_FALSE, &Model[0][0]); glUniformMatrix4fv(ViewID, 1, GL_FALSE, &View[0][0]); drawObject();

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  • What is the best way to create related types at runtime?

    - by SniperSmiley
    How do I determine the type of a class that is related to another class at runtime? I have figured out a solution, the only problem is that I ended up having to use a define that has to be used in all of the derived classes. Is there a simpler way to do this that doesn't need the define or a copy paste? Things to note: both the class and the related class will always have their respective base class, the different classes can share a related class, and as in the example I would like the control class to own the view. #include <iostream> #include <string> class model; class view { public: view( model *m ) {} virtual std::string display() { return "view"; } }; #define RELATED_CLASS(RELATED)\ typedef RELATED relatedType;\ virtual relatedType*createRelated(){\ return new relatedType(this);} class model { public: RELATED_CLASS(view) model() {} }; class otherView : public view { public: otherView( model *m ) : view(m) {} std::string display() { return "otherView"; } }; class otherModel : public model { public: RELATED_CLASS(otherView) otherModel() {} }; class control { public: control( model *m ) : m_(m), v_( m->createRelated() ) {} ~control() { delete v_; } std::string display() { return v_->display(); } model *m_; view *v_; }; int main( void ) { model m; otherModel om; model *pm = &om; control c1( &m ); control c2( &om ); control c3( pm ); std::cout << c1.display() << std::endl; std::cout << c2.display() << std::endl; std::cout << c3.display() << std::endl; }

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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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  • C++ interface inheritance problem

    - by james t
    Hey, i'm trying to create a c++ stomp client, my client constructor is : Client(std::string &server, short port, std::string &login, std::string &pass, Listener &listener); it gets a listener object which when Listener is the following interface : class Listener { virtual void message(StmpMessage message) =0; }; now i attempt to instantiate a client in a test class : class test : public virtual Listener { public: void message(StmpMessage message) { message.prettyPrint(); } int main(int argc, char* argv[]) { Client client("127.0.0.1", 61613, *this); return 0; } }; i'm sending this to the client because this is a listener object, i get the following error : /Users/mzruya/Documents/STOMPCPP/main.cpp:18: error: no matching function for call to 'Client::Client(const char [10], int, test&)' /Users/mzruya/Documents/STOMPCPP/Client.h:43: note: candidates are: Client::Client(std::string&, short int, std::string&, std::string&, Listener&) /Users/mzruya/Documents/STOMPCPP/Client.h:37: note: Client::Client(const Client&)

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  • boost.asio error on read from socket.

    - by niXman
    The following code of the client: typedef boost::array<char, 10> header_packet; header_packet header; boost::system::error_code error; ... /** send header */ boost::asio::write( _socket, boost::asio::buffer(header, header.size()), boost::asio::transfer_all(), error ); /** send body */ boost::asio::write( _socket, boost::asio::buffer(buffer, buffer.length()), boost::asio::transfer_all(), error ); of the server: struct header { boost::uint32_t header_length; boost::uint32_t id; boost::uint32_t body_length; }; static header unpack_header(const header_packet& data) { header hdr; sscanf(data.data(), "%02d%04d%04d", &hdr.header_length, &hdr.id, &hdr.body_length); return hdr; } void connection::start() { boost::asio::async_read( _socket, boost::asio::buffer(_header, _header.size()), boost::bind( &connection::read_header_handler, shared_from_this(), boost::asio::placeholders::error ) ); } /***************************************************************************/ void connection::read_header_handler(const boost::system::error_code& e) { if ( !e ) { std::cout << "readed header: " << _header.c_array() << std::endl; std::cout << constants::unpack_header(_header); boost::asio::async_read( _socket, boost::asio::buffer(_body, constants::unpack_header(_header).body_length), boost::bind( &connection::read_body_handler, shared_from_this(), boost::asio::placeholders::error ) ); } else { /** report error */ std::cout << "read header finished with error: " << e.message() << std::endl; } } /***************************************************************************/ void connection::read_body_handler(const boost::system::error_code& e) { if ( !e ) { std::cout << "readed body: " << _body.c_array() << std::endl; start(); } else { /** report error */ std::cout << "read body finished with error: " << e.message() << std::endl; } } On the server side the method read_header_handler() is called, but the method read_body_handler() is never called. Though the client has written down the data in a socket. The header is readed and decoded successfully. What's the error?

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  • Cheapest way of binding local variable to closure

    - by mmotorny
    I believe following to be a cheapest way of binding local variable to closure: void ByRValueReference(A&& a) { } std::function<void ()> CreateClosureByRValueReference() { A a; std::function<void ()> f = std::bind(&ByRValueReference, std::move(a)); // !!! return f; } However, it does not compile under Clang 3.1: error: no viable conversion from '__bind<void (*)(A &&), A>' to 'std::function<void ()>' and gcc 4.6.1: /usr/include/c++/4.6/functional:1778:2: error: no match for call to ‘(std::_Bind<void (*(A))(A&&)>) ()’ Am I violating the standard or it's just broken standard libraries?

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  • Can't insert a number into a C++ custom streambuf/ostream

    - by 0xbe5077ed
    I have written a custom std::basic_streambuf and std::basic_ostream because I want an output stream that I can get a JNI string from in a manner similar to how you can call std::ostringstream::str(). These classes are quite simple. namespace myns { class jni_utf16_streambuf : public std::basic_streambuf<char16_t> { JNIEnv * d_env; std::vector<char16_t> d_buf; virtual int_type overflow(int_type); public: jni_utf16_streambuf(JNIEnv *); jstring jstr() const; }; typedef std::basic_ostream<char16_t, std::char_traits<char16_t>> utf16_ostream; class jni_utf16_ostream : public utf16_ostream { jni_utf16_streambuf d_buf; public: jni_utf16_ostream(JNIEnv *); jstring jstr() const; }; // ... } // namespace myns In addition, I have made four overloads of operator<<, all in the same namespace: namespace myns { // ... utf16_ostream& operator<<(utf16_ostream&, jstring) throw(std::bad_cast); utf16_ostream& operator<<(utf16_ostream&, const char *); utf16_ostream& operator<<(utf16_ostream&, const jni_utf16_string_region&); jni_utf16_ostream& operator<<(jni_utf16_ostream&, jstring); // ... } // namespace myns The implementation of jni_utf16_streambuf::overflow(int_type) is trivial. It just doubles the buffer width, puts the requested character, and sets the base, put, and end pointers correctly. It is tested and I am quite sure it works. The jni_utf16_ostream works fine inserting unicode characters. For example, this works fine and results in the stream containing "hello, world": myns::jni_utf16_ostream o(env); o << u"hello, wor" << u'l' << u'd'; My problem is as soon as I try to insert an integer value, the stream's bad bit gets set, for example: myns::jni_utf16_ostream o(env); if (o.badbit()) throw "bad bit before"; // does not throw int32_t x(5); o << x; if (o.badbit()) throw "bad bit after"; // throws :( I don't understand why this is happening! Is there some other method on std::basic_streambuf I need to be implementing????

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  • Making a Wrapper class for ActiveMQ

    - by DarthVader
    I want to make a Wrapper class for ActiveMQ which will have only send and get functions. I want to wrap them in a static class. Users can use this client and send, get messages to the activemq instance. I want this process to be transparent. There are two classes in this link My only handicap is, i need to this in c++ and not sure where to start. I havent used c++ for ages and now not sure how I can create this wrapper class. I m giving it a try as follows: // .h file #include <stdlib.h> #include <iostream> using namespace std; class ActiveMQWrapper { public: static void send(std::string message); static std::string get(); }; // .cpp file #include<string> #include<iostream> #include "ActiveMQWrapper.h" void ActiveMQWrapper::send(std::string message){ std::cout<<message; } std::string ActiveMQWrapper::get(){ return "test"; } // test file #include <string> #include <iostream> #include "ActiveMQWrapper.h" int main() { std::string foo ="test"; ActiveMQWrapper::send(foo); std::cout<<ActiveMQWrapper::get(); return 1; } When I added the following to .h file, hell breaks loose. Do you think I should seperate this impl to a factory and initialize and instance and return to the wrapper above? How do i deal with all the dependencies? private: Connection* connection; Session* session; Destination* destination; MessageProducer* producer; int numMessages; bool useTopic; bool sessionTransacted; std::string brokerURI; and the header files, i get several messages as errors, which complains about the path. How can i get this correct? I eventually want to build a Factory, get an instance and send or get the messages to the queue. is there a code sample i can look into to get this right? essential i want to use the functionality of only this producer and consumer. Edit: I understand there is no such thing as static class in C++ . This is my reference.

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  • Why isn't the compiler smarter in this const function overloading problem?

    - by Frank
    The following code does not compile: #include <iostream> class Foo { std::string s; public: const std::string& GetString() const { return s; } std::string* GetString() { return &s; } }; int main(int argc, char** argv){ Foo foo; const std::string& s = foo.GetString(); // error return 0; } I get the following error: const1.cc:11: error: invalid initialization of reference of type 'const std::string&' from expression of type 'std::string* It does make some sense because foo is not of type const Foo, but just Foo, so the compiler wants to use the non-const function. But still, why can't it recognize that I want to call the const GetString function, by looking at the (type of) variable I assign it to? I found this kind of surprising.

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  • xutility file???

    - by user574290
    Hi all. I'm trying to use c code with opencv in face detection and counting, but I cannot build the source. I am trying to compile my project and I am having a lot of problems with a line in the xutility file. the error message show that it error with xutility file. Please help me, how to solve this problem? this is my code // Include header files #include "stdafx.h" #include "cv.h" #include "highgui.h" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <math.h> #include <float.h> #include <limits.h> #include <time.h> #include <ctype.h> #include <iostream> #include <fstream> #include <vector> using namespace std; #ifdef _EiC #define WIN32 #endif int countfaces=0; int numFaces = 0; int k=0 ; int list=0; char filelist[512][512]; int timeCount = 0; static CvMemStorage* storage = 0; static CvHaarClassifierCascade* cascade = 0; void detect_and_draw( IplImage* image ); void WriteInDB(); int found_face(IplImage* img,CvPoint pt1,CvPoint pt2); int load_DB(char * filename); const char* cascade_name = "C:\\Program Files\\OpenCV\\OpenCV2.1\\data\\haarcascades\\haarcascade_frontalface_alt_tree.xml"; // BEGIN NEW CODE #define WRITEVIDEO char* outputVideo = "c:\\face_counting1_tracked.avi"; //int faceCount = 0; int posBuffer = 100; int persistDuration = 10; //faces can drop out for 10 frames int timestamp = 0; float sameFaceDistThreshold = 30; //pixel distance CvPoint facePositions[100]; int facePositionsTimestamp[100]; float distance( CvPoint a, CvPoint b ) { float dist = sqrt(float ( (a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y) ) ); return dist; } void expirePositions() { for (int i = 0; i < posBuffer; i++) { if (facePositionsTimestamp[i] <= (timestamp - persistDuration)) //if a tracked pos is older than three frames { facePositions[i] = cvPoint(999,999); } } } void updateCounter(CvPoint center) { bool newFace = true; for(int i = 0; i < posBuffer; i++) { if (distance(center, facePositions[i]) < sameFaceDistThreshold) { facePositions[i] = center; facePositionsTimestamp[i] = timestamp; newFace = false; break; } } if(newFace) { //push out oldest tracker for(int i = 1; i < posBuffer; i++) { facePositions[i] = facePositions[i - 1]; } //put new tracked position on top of stack facePositions[0] = center; facePositionsTimestamp[0] = timestamp; countfaces++; } } void drawCounter(IplImage* image) { // Create Font char buffer[5]; CvFont font; cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, .5, .5, 0, 1); cvPutText(image, "Faces:", cvPoint(20, 20), &font, CV_RGB(0,255,0)); cvPutText(image, itoa(countfaces, buffer, 10), cvPoint(80, 20), &font, CV_RGB(0,255,0)); } #ifdef WRITEVIDEO CvVideoWriter* videoWriter = cvCreateVideoWriter(outputVideo, -1, 30, cvSize(240, 180)); #endif //END NEW CODE int main( int argc, char** argv ) { CvCapture* capture = 0; IplImage *frame, *frame_copy = 0; int optlen = strlen("--cascade="); const char* input_name; if( argc > 1 && strncmp( argv[1], "--cascade=", optlen ) == 0 ) { cascade_name = argv[1] + optlen; input_name = argc > 2 ? argv[2] : 0; } else { cascade_name = "C:\\Program Files\\OpenCV\\OpenCV2.1\\data\\haarcascades\\haarcascade_frontalface_alt_tree.xml"; input_name = argc > 1 ? argv[1] : 0; } cascade = (CvHaarClassifierCascade*)cvLoad( cascade_name, 0, 0, 0 ); if( !cascade ) { fprintf( stderr, "ERROR: Could not load classifier cascade\n" ); fprintf( stderr, "Usage: facedetect --cascade=\"<cascade_path>\" [filename|camera_index]\n" ); return -1; } storage = cvCreateMemStorage(0); //if( !input_name || (isdigit(input_name[0]) && input_name[1] == '\0') ) // capture = cvCaptureFromCAM( !input_name ? 0 : input_name[0] - '0' ); //else capture = cvCaptureFromAVI( "c:\\face_counting1.avi" ); cvNamedWindow( "result", 1 ); if( capture ) { for(;;) { if( !cvGrabFrame( capture )) break; frame = cvRetrieveFrame( capture ); if( !frame ) break; if( !frame_copy ) frame_copy = cvCreateImage( cvSize(frame->width,frame->height), IPL_DEPTH_8U, frame->nChannels ); if( frame->origin == IPL_ORIGIN_TL ) cvCopy( frame, frame_copy, 0 ); else cvFlip( frame, frame_copy, 0 ); detect_and_draw( frame_copy ); if( cvWaitKey( 30 ) >= 0 ) break; } cvReleaseImage( &frame_copy ); cvReleaseCapture( &capture ); } else { if( !input_name || (isdigit(input_name[0]) && input_name[1] == '\0')) cvNamedWindow( "result", 1 ); const char* filename = input_name ? input_name : (char*)"lena.jpg"; IplImage* image = cvLoadImage( filename, 1 ); if( image ) { detect_and_draw( image ); cvWaitKey(0); cvReleaseImage( &image ); } else { /* assume it is a text file containing the list of the image filenames to be processed - one per line */ FILE* f = fopen( filename, "rt" ); if( f ) { char buf[1000+1]; while( fgets( buf, 1000, f ) ) { int len = (int)strlen(buf); while( len > 0 && isspace(buf[len-1]) ) len--; buf[len] = '\0'; image = cvLoadImage( buf, 1 ); if( image ) { detect_and_draw( image ); cvWaitKey(0); cvReleaseImage( &image ); } } fclose(f); } } } cvDestroyWindow("result"); #ifdef WRITEVIDEO cvReleaseVideoWriter(&videoWriter); #endif return 0; } void detect_and_draw( IplImage* img ) { static CvScalar colors[] = { {{0,0,255}}, {{0,128,255}}, {{0,255,255}}, {{0,255,0}}, {{255,128,0}}, {{255,255,0}}, {{255,0,0}}, {{255,0,255}} }; double scale = 1.3; IplImage* gray = cvCreateImage( cvSize(img->width,img->height), 8, 1 ); IplImage* small_img = cvCreateImage( cvSize( cvRound (img->width/scale), cvRound (img->height/scale)), 8, 1 ); CvPoint pt1, pt2; int i; cvCvtColor( img, gray, CV_BGR2GRAY ); cvResize( gray, small_img, CV_INTER_LINEAR ); cvEqualizeHist( small_img, small_img ); cvClearMemStorage( storage ); if( cascade ) { double t = (double)cvGetTickCount(); CvSeq* faces = cvHaarDetectObjects( small_img, cascade, storage, 1.1, 2, 0/*CV_HAAR_DO_CANNY_PRUNING*/, cvSize(30, 30) ); t = (double)cvGetTickCount() - t; printf( "detection time = %gms\n", t/((double)cvGetTickFrequency()*1000.) ); if (faces) { //To save the detected faces into separate images, here's a quick and dirty code: char filename[6]; for( i = 0; i < (faces ? faces->total : 0); i++ ) { /* CvRect* r = (CvRect*)cvGetSeqElem( faces, i ); CvPoint center; int radius; center.x = cvRound((r->x + r->width*0.5)*scale); center.y = cvRound((r->y + r->height*0.5)*scale); radius = cvRound((r->width + r->height)*0.25*scale); cvCircle( img, center, radius, colors[i%8], 3, 8, 0 );*/ // Create a new rectangle for drawing the face CvRect* r = (CvRect*)cvGetSeqElem( faces, i ); // Find the dimensions of the face,and scale it if necessary pt1.x = r->x*scale; pt2.x = (r->x+r->width)*scale; pt1.y = r->y*scale; pt2.y = (r->y+r->height)*scale; // Draw the rectangle in the input image cvRectangle( img, pt1, pt2, CV_RGB(255,0,0), 3, 8, 0 ); CvPoint center; int radius; center.x = cvRound((r->x + r->width*0.5)*scale); center.y = cvRound((r->y + r->height*0.5)*scale); radius = cvRound((r->width + r->height)*0.25*scale); cvCircle( img, center, radius, CV_RGB(255,0,0), 3, 8, 0 ); //update counter updateCounter(center); int y=found_face(img,pt1,pt2); if(y==0) countfaces++; }//end for printf("Number of detected faces: %d\t",countfaces); }//end if //delete old track positions from facePositions array expirePositions(); timestamp++; //draw counter drawCounter(img); #ifdef WRITEVIDEO cvWriteFrame(videoWriter, img); #endif cvShowImage( "result", img ); cvDestroyWindow("Result"); cvReleaseImage( &gray ); cvReleaseImage( &small_img ); }//end if } //end void int found_face(IplImage* img,CvPoint pt1,CvPoint pt2) { /*if (faces) {*/ CvSeq* faces = cvHaarDetectObjects( img, cascade, storage, 1.1, 2, CV_HAAR_DO_CANNY_PRUNING, cvSize(40, 40) ); int i=0; char filename[512]; for( i = 0; i < (faces ? faces->total : 0); i++ ) {//int scale = 1, i=0; //i=iface; //char filename[512]; /* extract the rectanlges only */ // CvRect face_rect = *(CvRect*)cvGetSeqElem( faces, i); CvRect face_rect = *(CvRect*)cvGetSeqElem( faces, i); //IplImage* gray_img = cvCreateImage( cvGetSize(img), IPL_DEPTH_8U, 1 ); IplImage* clone = cvCreateImage (cvSize(img->width, img->height), IPL_DEPTH_8U, img->nChannels ); IplImage* gray = cvCreateImage (cvSize(img->width, img->height), IPL_DEPTH_8U, 1 ); cvCopy (img, clone, 0); cvNamedWindow ("ROI", CV_WINDOW_AUTOSIZE); cvCvtColor( clone, gray, CV_RGB2GRAY ); face_rect.x = pt1.x; face_rect.y = pt1.y; face_rect.width = abs(pt1.x - pt2.x); face_rect.height = abs(pt1.y - pt2.y); cvSetImageROI ( gray, face_rect); //// * rectangle = cvGetImageROI ( clone ); face_rect = cvGetImageROI ( gray ); cvShowImage ("ROI", gray); k++; char *name=0; name=(char*) calloc(512, 1); sprintf(name, "Image%d.pgm", k); cvSaveImage(name, gray); //////////////// for(int j=0;j<512;j++) filelist[list][j]=name[j]; list++; WriteInDB(); //int found=SIFT("result.txt",name); cvResetImageROI( gray ); //return found; return 0; // }//end if }//end for }//end void void WriteInDB() { ofstream myfile; myfile.open ("result.txt"); for(int i=0;i<512;i++) { if(strcmp(filelist[i],"")!=0) myfile << filelist[i]<<"\n"; } myfile.close(); } Error 3 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int Error 8 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int Error 13 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 18 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 23 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 10 error C2868: 'std::iterator_traits<_Iter>::value_type' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 25 error C2868: 'std::iterator_traits<_Iter>::reference' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 20 error C2868: 'std::iterator_traits<_Iter>::pointer' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 5 error C2868: 'std::iterator_traits<_Iter>::iterator_category' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 15 error C2868: 'std::iterator_traits<_Iter>::difference_type' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 9 error C2602: 'std::iterator_traits<_Iter>::value_type' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 24 error C2602: 'std::iterator_traits<_Iter>::reference' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 19 error C2602: 'std::iterator_traits<_Iter>::pointer' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 4 error C2602: 'std::iterator_traits<_Iter>::iterator_category' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 14 error C2602: 'std::iterator_traits<_Iter>::difference_type' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 7 error C2146: syntax error : missing ';' before identifier 'value_type' c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 22 error C2146: syntax error : missing ';' before identifier 'reference' c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 17 error C2146: syntax error : missing ';' before identifier 'pointer' c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 2 error C2146: syntax error : missing ';' before identifier 'iterator_category' c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 12 error C2146: syntax error : missing ';' before identifier 'difference_type' c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 6 error C2039: 'value_type' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 21 error C2039: 'reference' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 16 error C2039: 'pointer' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 1 error C2039: 'iterator_category' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 11 error C2039: 'difference_type' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 766

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  • Can't figure out where race condition is occuring

    - by Nik
    I'm using Valgrind --tool=drd to check my application that uses Boost::thread. Basically, the application populates a set of "Book" values with "Kehai" values based on inputs through a socket connection. On a seperate thread, a user can connect and get the books send to them. Its fairly simple, so i figured using a boost::mutex::scoped_lock on the location that serializes the book and the location that clears out the book data should be suffice to prevent any race conditions. Here is the code: void Book::clear() { boost::mutex::scoped_lock lock(dataMutex); for(int i =NUM_KEHAI-1; i >= 0; --i) { bid[i].clear(); ask[i].clear(); } } int Book::copyChangedKehaiToString(char* dst) const { boost::mutex::scoped_lock lock(dataMutex); sprintf(dst, "%-4s%-13s",market.c_str(),meigara.c_str()); int loc = 17; for(int i = 0; i < Book::NUM_KEHAI; ++i) { if(ask[i].changed > 0) { sprintf(dst+loc,"A%i%-21s%-21s%-21s%-8s%-4s",i,ask[i].price.c_str(),ask[i].volume.c_str(),ask[i].number.c_str(),ask[i].postTime.c_str(),ask[i].status.c_str()); loc += 77; } } for(int i = 0; i < Book::NUM_KEHAI; ++i) { if(bid[i].changed > 0) { sprintf(dst+loc,"B%i%-21s%-21s%-21s%-8s%-4s",i,bid[i].price.c_str(),bid[i].volume.c_str(),bid[i].number.c_str(),bid[i].postTime.c_str(),bid[i].status.c_str()); loc += 77; } } return loc; } The clear() function and the copyChangedKehaiToString() function are called in the datagetting thread and data sending thread,respectively. Also, as a note, the class Book: struct Book { private: Book(const Book&); Book& operator=(const Book&); public: static const int NUM_KEHAI=10; struct Kehai; friend struct Book::Kehai; struct Kehai { private: Kehai& operator=(const Kehai&); public: std::string price; std::string volume; std::string number; std::string postTime; std::string status; int changed; Kehai(); void copyFrom(const Kehai& other); Kehai(const Kehai& other); inline void clear() { price.assign(""); volume.assign(""); number.assign(""); postTime.assign(""); status.assign(""); changed = -1; } }; std::vector<Kehai> bid; std::vector<Kehai> ask; tm recTime; mutable boost::mutex dataMutex; Book(); void clear(); int copyChangedKehaiToString(char * dst) const; }; When using valgrind --tool=drd, i get race condition errors such as the one below: ==26330== Conflicting store by thread 1 at 0x0658fbb0 size 4 ==26330== at 0x653AE68: std::string::_M_mutate(unsigned int, unsigned int, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x653AFC9: std::string::_M_replace_safe(unsigned int, unsigned int, char const*, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x653B064: std::string::assign(char const*, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x653B134: std::string::assign(char const*) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x8055D64: Book::Kehai::clear() (Book.h:50) ==26330== by 0x8094A29: Book::clear() (Book.cpp:78) ==26330== by 0x808537E: RealKernel::start() (RealKernel.cpp:86) ==26330== by 0x804D15A: main (main.cpp:164) ==26330== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.8 ==26330== Other segment start (thread 2) ==26330== at 0x400BB59: pthread_mutex_unlock (drd_pthread_intercepts.c:633) ==26330== by 0xC59565: pthread_mutex_unlock (in /lib/libc-2.5.so) ==26330== by 0x805477C: boost::mutex::unlock() (mutex.hpp:56) ==26330== by 0x80547C9: boost::unique_lock<boost::mutex>::~unique_lock() (locks.hpp:340) ==26330== by 0x80949BA: Book::copyChangedKehaiToString(char*) const (Book.cpp:134) ==26330== by 0x80937EE: BookSerializer::serializeBook(Book const&, std::string const&) (BookSerializer.cpp:41) ==26330== by 0x8092D05: BookSnapshotManager::getSnaphotDataList() (BookSnapshotManager.cpp:72) ==26330== by 0x8088179: SnapshotServer::getDataList() (SnapshotServer.cpp:246) ==26330== by 0x808870F: SnapshotServer::run() (SnapshotServer.cpp:183) ==26330== by 0x808BAF5: boost::_mfi::mf0<void, RealThread>::operator()(RealThread*) const (mem_fn_template.hpp:49) ==26330== by 0x808BB4D: void boost::_bi::list1<boost::_bi::value<RealThread*> >::operator()<boost::_mfi::mf0<void, RealThread>, boost::_bi::list0>(boost::_bi::type<void>, boost::_mfi::mf0<void, RealThread>&, boost::_bi::list0&, int) (bind.hpp:253) ==26330== by 0x808BB90: boost::_bi::bind_t<void, boost::_mfi::mf0<void, RealThread>, boost::_bi::list1<boost::_bi::value<RealThread*> > >::operator()() (bind_template.hpp:20) ==26330== Other segment end (thread 2) ==26330== at 0x400B62A: pthread_mutex_lock (drd_pthread_intercepts.c:580) ==26330== by 0xC59535: pthread_mutex_lock (in /lib/libc-2.5.so) ==26330== by 0x80546B8: boost::mutex::lock() (mutex.hpp:51) ==26330== by 0x805473B: boost::unique_lock<boost::mutex>::lock() (locks.hpp:349) ==26330== by 0x8054769: boost::unique_lock<boost::mutex>::unique_lock(boost::mutex&) (locks.hpp:227) ==26330== by 0x8094711: Book::copyChangedKehaiToString(char*) const (Book.cpp:113) ==26330== by 0x80937EE: BookSerializer::serializeBook(Book const&, std::string const&) (BookSerializer.cpp:41) ==26330== by 0x808870F: SnapshotServer::run() (SnapshotServer.cpp:183) ==26330== by 0x808BAF5: boost::_mfi::mf0<void, RealThread>::operator()(RealThread*) const (mem_fn_template.hpp:49) ==26330== by 0x808BB4D: void boost::_bi::list1<boost::_bi::value<RealThread*> >::operator()<boost::_mfi::mf0<void, RealThread>, boost::_bi::list0>(boost::_bi::type<void>, boost::_mfi::mf0<void, RealThread>&, boost::_bi::list0&, int) (bind.hpp:253) For the life of me, i can't figure out where the race condition is. As far as I can tell, clearing the kehai is done only after having taken the mutex, and the same holds true with copying it to a string. Does anyone have any ideas what could be causing this, or where I should look? Thank you kindly.

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  • Trouble passing a template function as an argument to another function in C++

    - by Darel
    Source of the problem -Accelerated C++, problem 8-5 I've written a small program that examines lines of string input, and tallies the number of times a word appears on a given line. The following code accomplishes this: #include <map> #include <iostream> #include <string> #include <vector> #include <list> #include <cctype> #include <iterator> using std::vector; using std::string; using std::cin; using std::cout; using std::endl; using std::getline; using std::istream; using std::string; using std::list; using std::map; using std::isspace; using std::ostream_iterator; using std::allocator; inline void keep_window_open() { cin.clear(); cout << "Please enter EOF to exit\n"; char ch; cin >> ch; return; } template <class Out> void split(const string& s, Out os) { vector<string> ret; typedef string::size_type string_size; string_size i = 0; // invariant: we have processed characters `['original value of `i', `i)' while (i != s.size()) { // ignore leading blanks // invariant: characters in range `['original `i', current `i)' are all spaces while (i != s.size() && isspace(s[i])) ++i; // find end of next word string_size j = i; // invariant: none of the characters in range `['original `j', current `j)' is a space while (j != s.size() && !isspace(s[j])) ++j; // if we found some nonwhitespace characters if (i != j) { // copy from `s' starting at `i' and taking `j' `\-' `i' chars *os++ = (s.substr(i, j - i)); i = j; } } } // find all the lines that refer to each word in the input map<string, vector<int> > xref(istream& in) // works // now try to pass the template function as an argument to function - what do i put for templated type? //map<string, vector<int> > xref(istream& in, void find_words(vector<string, typedef Out) = split) #LINE 1# { string line; int line_number = 0; map<string, vector<int> > ret; // read the next line while (getline(in, line)) { ++line_number; // break the input line into words vector<string> words; // works // #LINE 2# split(line, back_inserter(words)); // #LINE 3# //find_words(line, back_inserter(words)); // #LINE 4# attempting to use find_words as an argument to function // remember that each word occurs on the current line for (vector<string>::const_iterator it = words.begin(); it != words.end(); ++it) ret[*it].push_back(line_number); } return ret; } int main() { cout << endl << "Enter lines of text, followed by EOF (^Z):" << endl; // call `xref' using `split' by default map<string, vector<int> > ret = xref(cin); // write the results for (map<string, vector<int> >::const_iterator it = ret.begin(); it != ret.end(); ++it) { // write the word cout << it->first << " occurs on line(s): "; // followed by one or more line numbers vector<int>::const_iterator line_it = it->second.begin(); cout << *line_it; // write the first line number ++line_it; // write the rest of the line numbers, if any while (line_it != it->second.end()) { cout << ", " << *line_it; ++line_it; } // write a new line to separate each word from the next cout << endl; } keep_window_open(); return 0; } As you can see, the split function is a template function to handle various types of output iterators as desired. My problem comes when I try to generalize the xref function by passing in the templated split function as an argument. I can't seem to get the type correct. So my question is, can you pass a template function to another function as an argument, and if so, do you have to declare all types before passing it? Or can the compiler infer the types from the way the templated function is used in the body? To demonstrate the errors I get, comment out the existing xref function header, and uncomment the alternate header I'm trying to get working (just below the following commment line.) Also comment the lines tagged LINE 2 and LINE 3 and uncomment LINE 4, which is attempting to use the argument find_words (which defaults to split.) Thanks for any feedback!

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  • Achieving forward compatibility with C++11

    - by mcmcc
    I work on a large software application that must run on several platforms. Some of these platforms support some features of C++11 (e.g. MSVS 2010) and some don't support any (e.g. GCC 4.3.x). I see this situation continuing on for several years (my best guess: 3-5 years). Given that, I would like set up a compatibility interface such that (to whatever degree possible) people can write C++11 code that will still compile with older compilers with a minimum of maintenance. Overall, the goal is to minimize #ifdef's as much as reasonably possible while still enabling basic C++11 syntax/features on the platforms that support them, and provide emulation on the platforms that don't. Let's start with std::move(). The most obvious way to achieve compatibility would be to put something like this in a common header file: #if !defined(HAS_STD_MOVE) namespace std { // C++11 emulation template <typename T> inline T& move(T& v) { return v; } template <typename T> inline const T& move(const T& v) { return v; } } #endif // !defined(HAS_STD_MOVE) This allow people to write things like std::vector<Thing> x = std::move(y); ... with impugnity. It does what they want in C++11 and it does the best it can in C++03. When we finally drop the last of the C++03 compilers, this code can remain as is. However, according to the standard, it is illegal to inject new symbols into the std namespace. That's the theory. My question is, practically speaking, is there any harm in doing this as a way of achieving forward compatibility?

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  • Why isn't my lighting working properly? Are my normals messed up?

    - by Radek Slupik
    I'm relatively new to OpenGL and I am trying to draw a 3D model (loaded from a 3ds file using lib3ds) using OpenGL with lighting, but about half of it is drawn in black. I set up the light as such: glEnable(GL_LIGHTING); glShadeModel(GL_SMOOTH); GLfloat ambientColor[] = {0.2f, 0.2f, 0.2f, 1.0f}; glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientColor); glEnable(GL_LIGHT0); GLfloat lightColor0[] = {1.0f, 1.0f, 1.0f, 1.0f}; GLfloat lightPos0[] = {4.0f, 0.0f, 8.0f, 0.0f}; glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColor0); glLightfv(GL_LIGHT0, GL_POSITION, lightPos0); The model is in a VBO and drawn using glDrawArrays. The normals are in a separate VBO, and the normals are calculated using lib3ds_mesh_calculate_vertex_normals: std::vector<std::array<float, 3>> normals; for (std::size_t i = 0; i < model->nmeshes; ++i) { auto& mesh = *model->meshes[i]; std::vector<float[3]> vertex_normals(mesh.nfaces * 3); lib3ds_mesh_calculate_vertex_normals(&mesh, vertex_normals.data()); for (std::size_t j = 0; j < mesh.nfaces; ++j) { auto& face = mesh.faces[j]; normals.push_back(make_array(vertex_normals[j])); } } glBindBuffer(GL_ARRAY_BUFFER, normal_vbo_); glBufferData(GL_ARRAY_BUFFER, normals.size() * sizeof(decltype(normals)::value_type), normals.data(), GL_STATIC_DRAW); The problem isn't the vertices; the model is drawn correctly when drawing it as a wireframe. I also fixed the normals in Blender using controlN. What could be the problem? Should I store the normals in a different order?

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  • Is this Ubuntu One DBus signal connection code correct?

    - by Chris Wilson
    This is my first time using DBus so I'm not entirely sure if I'm going about this the right way. I'm attempting to connect the the Ubuntu One DBus service and obtain login credentials for my app, however the slots I've connected to the DBus return signals detailed here never seem to be firing, despite a positive result being returned during the connection. Before I start looking for errors in the details relating to this specific service, could someone please tell me if this code would even work in the first place, or if I'm done something wrong here? int main() { UbuntuOneDBus *u1Dbus = new UbuntuOneDBus; if( u1Dbus->init() ){ qDebug() << "Message queued"; } } UbuntuOneDBus::UbuntuOneDBus() { service = "com.ubuntuone.Credentials"; path = "/credentials"; interface = "com.ubuntuone.CredentialsManagement"; method = "register"; signature = "a{ss} (Dict of {String, String})"; connectReturnSignals(); } bool UbuntuOneDBus::init() { QDBusMessage message = QDBusMessage::createMethodCall( service, path, interface, method ); bool queued = QDBusConnection::sessionBus().send( message ); return queued; } void UbuntuOneDBus::connectReturnSignals() { bool connectionSuccessful = false; connectionSuccessful = QDBusConnection::sessionBus().connect( service, path, interface, "CredentialsFound", "a{ss} (Dict of {String, String})", this, SLOT( credentialsFound() ) ); if( ! connectionSuccessful ) qDebug() << "Connection to DBus::CredentialsFound signal failed"; connectionSuccessful = QDBusConnection::systemBus().connect( service, path, interface, "CredentialsNotFound", "(nothing)", this, SLOT( credentialsNotFound() ) ); if( ! connectionSuccessful ) qDebug() << "Connection to DBus::CredentialsNotFound signal failed"; connectionSuccessful = QDBusConnection::systemBus().connect( service, path, interface, "CredentialsError", "a{ss} (Dict of {String, String})", this, SLOT( credential if( ! connectionSuccessful ) qDebug() << "Connection to DBus::CredentialsError signal failed"; } void UbuntuOneDBus::credentialsFound() { std::cout << "Credentials found" << std::endl; } void UbuntuOneDBus::credentialsNotFound() { std::cout << "Credentials not found" << std::endl; } void UbuntuOneDBus::credentialsError() { std::cout << "Credentials error" << std::endl; }

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  • Does putting types/functions inside namespace make compiler's parsing work easy?

    - by iammilind
    Retaining the names inside namespace will make compiler work less stressful!? For example: // test.cpp #include</*iostream,vector,string,map*/> class vec { /* ... */ }; Take 2 scenarios of main(): // scenario-1 using namespace std; // comment this line for scenario-2 int main () { vec obj; } For scenario-1 where using namespace std;, several type names from namespace std will come into global scope. Thus compiler will have to check against vec if any of the type is colliding with it. If it does then generate error. In scenario-2 where there is no using namespace, compiler just have to check vec with std, because that's the only symbol in global scope. I am interested to know that, shouldn't it make the compiler little faster ?

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  • Making an asynchronous Client with boost::asio

    - by tag
    Hello, i'm trying to make an asynchronous Client with boost::asio, i use the daytime asynchronous Server(in the tutorial). However sometimes the Client don't receive the Message, sometimes it do :O I'm sorry if this is too much Code, but i don't know what's wrong :/ Client: #include <iostream> #include <stdio.h> #include <ostream> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <boost/array.hpp> #include <boost/asio.hpp> using namespace std; using boost::asio::ip::tcp; class TCPClient { public: TCPClient(boost::asio::io_service& IO_Service, tcp::resolver::iterator EndPointIter); void Write(); void Close(); private: boost::asio::io_service& m_IOService; tcp::socket m_Socket; boost::array<char, 128> m_Buffer; size_t m_BufLen; private: void OnConnect(const boost::system::error_code& ErrorCode, tcp::resolver::iterator EndPointIter); void OnReceive(const boost::system::error_code& ErrorCode); void DoClose(); }; TCPClient::TCPClient(boost::asio::io_service& IO_Service, tcp::resolver::iterator EndPointIter) : m_IOService(IO_Service), m_Socket(IO_Service) { tcp::endpoint EndPoint = *EndPointIter; m_Socket.async_connect(EndPoint, boost::bind(&TCPClient::OnConnect, this, boost::asio::placeholders::error, ++EndPointIter)); } void TCPClient::Close() { m_IOService.post( boost::bind(&TCPClient::DoClose, this)); } void TCPClient::OnConnect(const boost::system::error_code& ErrorCode, tcp::resolver::iterator EndPointIter) { if (ErrorCode == 0) // Successful connected { m_Socket.async_receive(boost::asio::buffer(m_Buffer.data(), m_BufLen), boost::bind(&TCPClient::OnReceive, this, boost::asio::placeholders::error)); } else if (EndPointIter != tcp::resolver::iterator()) { m_Socket.close(); tcp::endpoint EndPoint = *EndPointIter; m_Socket.async_connect(EndPoint, boost::bind(&TCPClient::OnConnect, this, boost::asio::placeholders::error, ++EndPointIter)); } } void TCPClient::OnReceive(const boost::system::error_code& ErrorCode) { if (ErrorCode == 0) { std::cout << m_Buffer.data() << std::endl; m_Socket.async_receive(boost::asio::buffer(m_Buffer.data(), m_BufLen), boost::bind(&TCPClient::OnReceive, this, boost::asio::placeholders::error)); } else { DoClose(); } } void TCPClient::DoClose() { m_Socket.close(); } int main() { try { boost::asio::io_service IO_Service; tcp::resolver Resolver(IO_Service); tcp::resolver::query Query("127.0.0.1", "daytime"); tcp::resolver::iterator EndPointIterator = Resolver.resolve(Query); TCPClient Client(IO_Service, EndPointIterator); boost::thread ClientThread( boost::bind(&boost::asio::io_service::run, &IO_Service)); std::cout << "Client started." << std::endl; std::string Input; while (Input != "exit") { std::cin >> Input; } Client.Close(); ClientThread.join(); } catch (std::exception& e) { std::cerr << e.what() << std::endl; } } Server: http://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/tutorial/tutdaytime3/src.html Regards :)

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  • Longest Path in Boost Graph

    - by TheTSPSolver
    Hi, Sorry if this is a very basic questions for some of you but I'm new to C++ (let alone Boost Graph Library) and couldn't figure out this problem. So far I've been able to formulate/gather code to create a graph using the code below. Now I'm trying to figure out the code to find the longest path in this graph. Can someone please help with what would the code be? I was having trouble trying to figure out if/how to traverse through each node and/or edge when trying to find the path? I have to try to return all the nodes and edges in the longest path. Any help will be greatly appreciated. P.S. does anyone know if C++ has organized documentation like Javadoc?? #include <boost/graph/dag_shortest_paths.hpp> #include <boost/graph/adjacency_list.hpp> #include <windows.h> #include <iostream> int main() { using namespace boost; typedef adjacency_list<vecS, vecS, directedS, property<vertex_distance_t, double>, property<edge_weight_t, double> > graph_t; graph_t g(6); enum verts { stationA, stationB, stationC, stationD, stationE, stationF }; char name[] = "rstuvx"; add_edge(stationA, stationB, 5000.23, g); add_edge(stationA, stationC, 3001, g); add_edge(stationA, stationD, 2098.67, g); add_edge(stationA, stationE, 3298.84, g); add_edge(stationB, stationF, 2145, g); add_edge(stationC, stationF, 4290, g); add_edge(stationD, stationF, 2672.78, g); add_edge(stationE, stationF, 11143.876, g); add_edge(stationA, stationF, 1, g); //Display all the vertices typedef property_map<graph_t, vertex_index_t>::type IndexMap; IndexMap index = get(vertex_index, g); std::cout << "vertices(g) = "; typedef graph_traits<graph_t>::vertex_iterator vertex_iter; std::pair<vertex_iter, vertex_iter> vp; for (vp = vertices(g); vp.first != vp.second; ++vp.first) std::cout << index[*vp.first] << " "; std::cout << std::endl; // ... // Display all the edges // ... std::cout << "edges(g) = " << std::endl; graph_traits<graph_t>::edge_iterator ei, ei_end; for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei) std::cout << "(" << index[source(*ei, g)] << "," << index[target(*ei, g)] << ") \n"; std::cout << std::endl; // ...

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