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  • Boost Binary Endian parser not working?

    - by Hai
    I am studying how to use boost spirit Qi binary endian parser. I write a small test parser program according to here and basics examples, but it doesn't work proper. It gave me the msg:"Error:no match". Here is my code. #include "boost/spirit/include/qi.hpp" #include "boost/spirit/include/phoenix_core.hpp" #include "boost/spirit/include/phoenix_operator.hpp" #include "boost/spirit/include/qi_binary.hpp" // parsing binary data in various endianness template '<'typename P, typename T void binary_parser( char const* input, P const& endian_word_type, T& voxel, bool full_match = true) { using boost::spirit::qi::parse; char const* f(input); char const* l(f + strlen(f)); bool result1 = parse(f,l,endian_word_type,voxel); bool result2 =((!full_match) || (f ==l)); if ( result1 && result2) { //doing nothing, parsing data is pass to voxel alreay } else { std::cerr << "Error: not match!!" << std::endl; exit(1); } } typedef boost::uint16_t bs_int16; typedef boost::uint32_t bs_int32; int main ( int argc, char *argv[] ) { namespace qi = boost::spirit::qi; namespace ascii = boost::spirit::ascii; using qi::big_word; using qi::big_dword; boost::uint32_t ui; float uf; binary_parser("\x01\x02\x03\x04",big_word,ui); assert(ui=0x01020304); binary_parser("\x01\x02\x03\x04",big_word,uf); assert(uf=0x01020304); return 0; }' I almost copy the example, but why this binary parser doesn't work. I use Mac OS 10.5.8 and gcc 4.01 compiler.

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  • Problem in using a second call to send() in C

    - by Paulo Victor
    Hello. Right now I'm working in a simple Server that receives from client a code referring to a certain operation. The server receives this data and send back the signal that it's waiting for the proper data. /*Server Side*/ if (codigoOperacao == 0) { printf("A escolha foi 0\n"); int bytesSent = SOCKET_ERROR; char sendBuff[1080] = "0"; /*Here "send" returns an error msgm while trying to send back the signal*/ bytesSent = send(socketEscuta, sendBuff, 1080, 0); if (bytesSent == SOCKET_ERROR) { printf("Erro ao enviar"); return 0; } else { printf("Bytes enviados : %d\n", bytesSent); char structDesmontada[1080] = ""; bytesRecv = recebeMensagem(socketEscuta, structDesmontada); printf("structDesmontada : %s", structDesmontada); } } Following here is the client code responsible for sending the operation code and receiving the signal char sendMsg[1080] = "0"; char recvMsg[1080] = ""; bytesSent = send(socketCliente, sendMsg, sizeof(sendMsg), 0); printf("Enviei o codigo (%d)\n", bytesSent); /*Here the program blocks in a infinite loop since the server never send anything*/ while (bytesRecv == SOCKET_ERROR) { bytesRecv = recv(socketCliente, recvMsg, 1080, 0); if (bytesRecv > 0) { printf("Recebeu\n"); } Why this is happening only in the second attempt to send some data? Because the first call to send() works fine. Hope someone can help!! Thnks

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  • Providing less than operator for one element of a pair

    - by Koszalek Opalek
    What would be the most elegant way too fix the following code: #include <vector> #include <map> #include <set> using namespace std; typedef map< int, int > row_t; typedef vector< row_t > board_t; typedef row_t::iterator area_t; bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; int main( int argc, char* argv[] ) { int row_num; area_t it; set< pair< int, area_t > > queue; queue.insert( make_pair( row_num, it ) ); // does not compile }; One way to fix it is moving the definition of less< to namespace std (I know, you are not supposed to do it.) namespace std { bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; }; Another obvious solution is defining less than< for pair< int, area_t but I'd like to avoid that and be able to define the operator only for the one element of the pair where it is not defined.

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  • Expand chaining hashtable. Errors on code.

    - by FILIaS
    Expanding a hashtable with linked lists there are some errors and warnings. I wanna make sure that the following code is right (expand method) and find out what happens that raise these warnings/errors typedef struct { int length; struct List *head; struct List *tail; } HashTable; //resolving collisions using linked lists - chaining typedef struct { char *number; char *name; int time; struct List *next; }List; //on the insert method i wanna check hashtable's size, //if it seems appropriate there is the following code: //Note: hashtable variable is: Hashtable * ...... hashtable = expand(hashtable,number,name,time); /**WARNING**:assignment makes pointer from integer without a cast*/ HashTable* expand( HashTable* h ,char number[10],char* name,int time) /**error**: conflicting types for ‘expand’ previous implicit declaration of ‘expand’ was here*/ { HashTable* new; int n; clientsList *node,*next; PrimesIndex++; int new_size= primes[PrimesIndex]; /* double the size,odd length */ if (!(new=malloc((sizeof( List*))*new_size))) return NULL; for(n=0; n< h->length; ++n) { for(node=h[n].head; node; node=next) { add (&new, node->number, node->name,node->time); next=node->next;//// free(node); } } free(h); return new; }

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  • C++ casted realloc causing memory leak

    - by wyatt
    I'm using a function I found here to save a webpage to memory with cURL: struct WebpageData { char *pageData; size_t size; }; size_t storePage(void *input, size_t size, size_t nmemb, void *output) { size_t realsize = size * nmemb; struct WebpageData *page = (struct WebpageData *)output; page->pageData = (char *)realloc(page->pageData, page->size + realsize + 1); if(page->pageData) { memcpy(&(page->pageData[page->size]), input, realsize); page->size += realsize; page->pageData[page->size] = 0; } return realsize; } and find the line: page->pageData = (char *)realloc(page->pageData, page->size + realsize + 1); is causing a memory leak of a few hundred bytes per call. The only real change I've made from the original source is casting the line in question to a (char *), which my compiler (gcc, g++ specifically if it's a c/c++ issue, but gcc also wouldn't compile with the uncast statement) insisted upon, but I assume this is the source of the leak. Can anyone elucidate? Thanks

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  • C when to allocate and free memory - before function call, after function call...etc

    - by Keith P
    I am working with my first straight C project, and it has been a while since I worked on C++ for that matter. So the whole memory management is a bit fuzzy. I have a function that I created that will validate some input. In the simple sample below, it just ignores spaces: int validate_input(const char *input_line, char* out_value){ int ret_val = 0; /*false*/ int length = strlen(input_line); cout << "length = " << length << "\n"; out_value =(char*) malloc(sizeof(char) * length + 1); if (0 != length){ int number_found = 0; for (int x = 0; x < length; x++){ if (input_line[x] != ' '){ /*ignore space*/ /*get the character*/ out_value[number_found] = input_line[x]; number_found++; /*increment counter*/ } } out_value[number_found + 1] = '\0'; ret_val = 1; } return ret_val; } Instead of allocating memory inside the function for out_value, should I do it before I call the function and always expect the caller to allocate memory before passing into the function? As a rule of thumb, should any memory allocated inside of a function be always freed before the function returns?

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  • In DBD::CSV what does a /r in the f_ext attribute mean?

    - by sid_com
    Why does only the second example append the extension to the filename and what is the "/r" in ".csv/r" for. #!/usr/bin/env perl use warnings; use strict; use 5.012; use DBI; my $dbh = DBI->connect( "DBI:CSV:f_dir=/home/mm", { RaiseError => 1, f_ext => ".csv/r"} ); my $table = 'new_1'; $dbh->do( "DROP TABLE IF EXISTS $table" ); $dbh->do( "CREATE TABLE $table ( id INT, name CHAR, city CHAR )" ); my $sth_new = $dbh->prepare( "INSERT INTO $table( id, name, city ) VALUES ( ?, ?, ?, )" ); $sth_new->execute( 1, 'Smith', 'Greenville' ); $dbh->disconnect(); # -------------------------------------------------------- $dbh = DBI->connect( "DBI:CSV:f_dir=/home/mm", { RaiseError => 1 } ); $dbh->{f_ext} = ".csv/r"; $table = 'new_2'; $dbh->do( "DROP TABLE IF EXISTS $table" ); $dbh->do( "CREATE TABLE $table ( id INT, name CHAR, city CHAR )" ); $sth_new = $dbh->prepare( "INSERT INTO $table( id, name, city ) VALUES ( ?, ?, ?, )" ); $sth_new->execute( 1, 'Smith', 'Greenville' ); $dbh->disconnect();

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  • why can't i bind ipv6 socket to a linklocal address

    - by Haiyuan Zhang
    #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <stdio.h> void error(char *msg) { perror(msg); exit(0); } int main(int argc, char *argv[]) { int sock, length, fromlen, n; struct sockaddr_in6 server; struct sockaddr_in6 from; int portNr = 5555; char buf[1024]; length = sizeof (struct sockaddr_in6); sock=socket(AF_INET6, SOCK_DGRAM, 0); if (sock < 0) error("Opening socket"); bzero((char *)&server, length); server.sin6_family=AF_INET6; server.sin6_addr=in6addr_any; server.sin6_port=htons(portNr); inet_pton( AF_INET6, "fe80::21f:29ff:feed:2f7e", (void *)&server.sin6_addr.s6_addr); //inet_pton( AF_INET6, "::1", (void *)&server.sin6_addr.s6_addr); if (bind(sock,(struct sockaddr *)&server,length)<0) error("binding"); fromlen = sizeof(struct sockaddr_in6); while (1) { n = recvfrom(sock,buf,1024,0,(struct sockaddr *)&from,&fromlen); if (n < 0) error("recvfrom"); write(1,"Received a datagram: ",21); write(1,buf,n); n = sendto(sock,"Got your message\n",17, 0,(struct sockaddr *)&from,fromlen); if (n < 0) error("sendto"); } } when I compile and run the above code I got : binding: Invalid argument and if change to bind the ::1 and leave other thing unchanged in the source code, the code works! so could you tell me what's wrong with my code ? thanks in advance.

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  • Why is calling close() after fopen() not closing?

    - by Richard Morgan
    I ran across the following code in one of our in-house dlls and I am trying to understand the behavior it was showing: long GetFD(long* fd, const char* fileName, const char* mode) { string fileMode; if (strlen(mode) == 0 || tolower(mode[0]) == 'w' || tolower(mode[0]) == 'o') fileMode = string("w"); else if (tolower(mode[0]) == 'a') fileMode = string("a"); else if (tolower(mode[0]) == 'r') fileMode = string("r"); else return -1; FILE* ofp; ofp = fopen(fileName, fileMode.c_str()); if (! ofp) return -1; *fd = (long)_fileno(ofp); if (*fd < 0) return -1; return 0; } long CloseFD(long fd) { close((int)fd); return 0; } After repeated calling of GetFD with the appropriate CloseFD, the whole dll would no longer be able to do any file IO. I wrote a tester program and found that I could GetFD 509 times, but the 510th time would error. Using Process Explorer, the number of Handles did not increase. So it seems that the dll is reaching the limit for the number of open files; setting _setmaxstdio(2048) does increase the amount of times we can call GetFD. Obviously, the close() is working quite right. After a bit of searching, I replaced the fopen() call with: long GetFD(long* fd, const char* fileName, const char* mode) { *fd = (long)open(fileName, 2); if (*fd < 0) return -1; return 0; } Now, repeatedly calling GetFD/CloseFD works. What is going on here?

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  • How can I get Visual Studio 2010 to show Chinese comments properly

    - by Joe H
    I have some code from a Chinese business partner, but all of the comments in the code which are in Chinese. However, Visual Studio displays them as gibberish. How can I get them to display properly. Here is a code example with some comments converted to gibberish: //Á¬½Óµ½·þÎñÆ÷ void CTestAPIDlg::OnBnClickedButton2() { UpdateData(TRUE); //ÉèÖÃÊÇ·ñ¼Ç¼ÈÕÖ¾ m_ObjRSI->EnableLog(m_bIsOnLogReg,m_bIsOnLogComm); //ÅжÏÊÇ·ñÆôÓôúÀí if (m_bIsOnProxy) { //´úÀí²ÎÊý char proxyIP[64]; char proxyUserName[64]; char proxyUserPwd[64]; ZeroMemory(proxyIP,sizeof(proxyIP)); ZeroMemory(proxyUserName,sizeof(proxyUserName)); ZeroMemory(proxyUserPwd,sizeof(proxyUserPwd)); //×¢£º´Ë´¦ÒòΪÊÇʹÓÃunicode±àÒ룬ËùÒÔÒª×Ö·ûת»»£¬ÏÂͬ. WideCharToMultiByte(CP_ACP,0,m_strProxyIP,-1,proxyIP,64,NULL,NULL); WideCharToMultiByte(CP_ACP,0,m_strProxyUserName,-1,proxyUserName,64,NULL,NULL); WideCharToMultiByte(CP_ACP,0,m_strProxyPwd,-1,proxyUserPwd,64,NULL,NULL); //ÉèÖôúÀí²ÎÊý m_ObjRSI->SetProxyParam(proxyIP,m_iProxyPort,proxyUserName,proxyUserPwd,m_iProxyType); } //Á¬½Ó²ÎÊý char szIp[64]; ZeroMemory(szIp,sizeof(szIp)); WideCharToMultiByte(CP_ACP,0,m_strIP,-1,szIp,64,NULL,NULL); //Á¬½Ó·þÎñÆ÷ m_ObjRSI->SetCommParam(szIp,m_iPort,m_iCheckIDPort); m_ObjRSI->StartService(); //ÉèÖð´Å¥×´Ì¬ ((CButton*)GetDlgItem(IDC_CHECK2))->EnableWindow(FALSE); ((CButton*)GetDlgItem(IDC_CHECK3))->EnableWindow(FALSE); } Thanks in advance for any help...

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  • How can I modified the value of a string defined in a struc?

    - by Eric
    Hi, I have the following code in c++: define TAM 4000 define NUMPAGS 512 struct pagina { bitset<12 direccion; char operacion; char permiso; string *dato; int numero; }; void crearPagina(pagina* pag[], int pos, int dir) { pagina * paginas = (pagina*)malloc(sizeof(char) * TAM); paginas - direccion = bitset<12 (dir); paginas - operacion = 'n'; paginas - permiso = 'n'; string **tempDato = &paginas - dato; char *temp = " "; **tempDato = temp; paginas - numero = 0; pag[pos] = paginas; } I want to modify the value of the variable called "string *dato" in the struct pagina but, everytime I want to assing a new value, the compiler throws a segmentation fault. In this case I'm using a pointer to string, but I have also tried with a string. In a few words I want to do the following: pagina - dato = "test"; Any idea? Thanks in advance!!!

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  • multiple definition in header file

    - by Jérôme
    Here is a small code-example from which I'd like to ask a question : complex.h : #ifndef COMPLEX_H #define COMPLEX_H #include <iostream> class Complex { public: Complex(float Real, float Imaginary); float real() const { return m_Real; }; private: friend std::ostream& operator<<(std::ostream& o, const Complex& Cplx); float m_Real; float m_Imaginary; }; std::ostream& operator<<(std::ostream& o, const Complex& Cplx) { return o << Cplx.m_Real << " i" << Cplx.m_Imaginary; } #endif // COMPLEX_H complex.cpp : #include "complex.h" Complex::Complex(float Real, float Imaginary) { m_Real = Real; m_Imaginary = Imaginary; } main.cpp : #include "complex.h" #include <iostream> int main() { Complex Foo(3.4, 4.5); std::cout << Foo << "\n"; return 0; } When compiling this code, I get the following error : multiple definition of operator<<(std::ostream&, Complex const&) I've found that making this fonction inline solves the problem, but I don't understand why. Why does the compiler complain about multiple definition ? My header file is guarded (with #define COMPLEX_H). And, if complaining about the operator<< fonction, why not complain about the public real() fonction, which is defined in the header as well ? And is there another solution as using the inline keyword ?

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  • How to convert string with double high/wide characters to normal string [VC++6]

    - by Shaitan00
    My application typically recieves a string in the following format: " Item $5.69 " Some contants I always expect: - the LENGHT always 20 characters - the start index of the text always [5] - and most importantly the index of the DECIMAL for the price always [14] In order to identify this string correctly I validate all the expected contants listed above .... Some of my clients have now started sending the string with Doube-High / Double-Wide values (pair of characters which represent a single readable character) similar to the following: " Item $x80x90.x81x91x82x92 " For testing I simply scan the string character-by-character, compare char[i] and char[i+1] and replace these pairs with their corresponding single character when a match is found (works fine) as follows: [Code] for (int i=0; i < sData.length(); i++) { char ch = sData[i] & 0xFF; char ch2 = sData[i+1] & 0xFF; if (ch == '\x80' && ch2 == '\x90') zData.replace("\x80\x90", "0"); else if (ch == '\x81' && ch2 == '\x91') zData.replace("\x81\x91", "1"); else if (ch == '\x82' && ch2 == '\x92') zData.replace("\x82\x92", "2"); ... ... ... } [/Code] But the result is something like this: " Item $5.69 " Notice how this no longer matches my expectation: the lenght is now 17 (instead of 20) due to the 3 conversions and the decimal is now at index 13 (instead of 14) due to the conversion of the "5" before the decimal point. Ideally I would like to convert the string to a normal readable format keeping the constants (length, index of text, index of decimal) at the same place (so the rest of my application is re-usable) ... or any other suggestion (I'm pretty much stuck with this)... Is there a STANDARD way of dealing with these type of characters? Any help would be greatly appreciated, I've been stuck on this for a while now ... Thanks,

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  • c++ File input/output

    - by Myx
    Hi: I am trying to read from a file using fgets and sscanf. In my file, I have characters on each line of the while which I wish to put into a vector. So far, I have the following: FILE *fp; fp = fopen(filename, "r"); if(!fp) { fprintf(stderr, "Unable to open file %s\n", filename); return 0; } // Read file int line_count = 0; char buffer[1024]; while(fgets(buffer, 1023, fp)) { // Increment line counter line_count++; char *bufferp = buffer; ... while(*bufferp != '\n') { char *tmp; if(sscanf(bufferp, "%c", tmp) != 1) { fprintf(stderr, "Syntax error reading axiom on " "line %d in file %s\n", line_count, filename); return 0; } axiom.push_back(tmp); printf("put %s in axiom vector\n", axiom[axiom.size()-1]); // increment buffer pointer bufferp++; } } my axiom vector is defined as vector<char *> axiom;. When I run my program, I get a seg fault. It happens when I do the sscanf. Any suggestions on what I'm doing wrong?

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  • virtual methods and template classes

    - by soxs060389
    Hi I got over a problem, I think a very specific one. I've got 2 classes, a B aseclass and a D erived class (from B aseclass). B is a template class ( or class template) and has a pure virtual method virutal void work(const T &dummy) = 0; The D erived class is supposed to reimplement this, but as D is Derived from B rather than D being another template class, the compiler spits at me that virtual functions and templates don't work at once. Any ideas how to acomplish what I want? I am thankfull for any thoughts and Ideas, especially if you allready worked out that problem this class is fixed aka AS IS, I can not edit this without breaking existing code base template <typename T> class B { public: ... virtual void work(const T &dummy) = 0; .. }; take int* as an example class D : public B<int*>{ ... virtual void work(const int* &dummy){ /* put work code here */ } .. }; Edit: The compiler tells me, that void B<T>::work(const T&) [with T = int*] is pure virtual within D

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  • Reading a C/C++ data structure in C# from a byte array

    - by Chris Miller
    What would be the best way to fill a C# struct from a byte[] array where the data was from a C/C++ struct? The C struct would look something like this (my C is very rusty): typedef OldStuff { CHAR Name[8]; UInt32 User; CHAR Location[8]; UInt32 TimeStamp; UInt32 Sequence; CHAR Tracking[16]; CHAR Filler[12];} And would fill something like this: [StructLayout(LayoutKind.Explicit, Size = 56, Pack = 1)]public struct NewStuff{ [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)] [FieldOffset(0)] public string Name; [MarshalAs(UnmanagedType.U4)] [FieldOffset(8)] public uint User; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)] [FieldOffset(12)] public string Location; [MarshalAs(UnmanagedType.U4)] [FieldOffset(20)] public uint TimeStamp; [MarshalAs(UnmanagedType.U4)] [FieldOffset(24)] public uint Sequence; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)] [FieldOffset(28)] public string Tracking;} What is best way to copy OldStuff to NewStuff, if OldStuff was passed as byte[] array? I'm currently doing something like the following, but it feels kind of clunky. GCHandle handle;NewStuff MyStuff;int BufferSize = Marshal.SizeOf(typeof(NewStuff));byte[] buff = new byte[BufferSize];Array.Copy(SomeByteArray, 0, buff, 0, BufferSize);handle = GCHandle.Alloc(buff, GCHandleType.Pinned);MyStuff = (NewStuff)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(NewStuff));handle.Free(); Is there better way to accomplish this?

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  • DBD::CSV: Append-extension-question

    - by sid_com
    Why does only the second example append the extension to the filename and what is the "/r" in ".csv/r" for. #!/usr/bin/env perl use warnings; use strict; use 5.012; use DBI; my $dbh = DBI->connect( "DBI:CSV:f_dir=/home/mm", { RaiseError => 1, f_ext => ".csv/r"} ); my $table = 'new_1'; $dbh->do( "DROP TABLE IF EXISTS $table" ); $dbh->do( "CREATE TABLE $table ( id INT, name CHAR, city CHAR )" ); my $sth_new = $dbh->prepare( "INSERT INTO $table( id, name, city ) VALUES ( ?, ?, ?, )" ); $sth_new->execute( 1, 'Smith', 'Greenville' ); $dbh->disconnect(); # -------------------------------------------------------- $dbh = DBI->connect( "DBI:CSV:f_dir=/home/mm", { RaiseError => 1 } ); $dbh->{f_ext} = ".csv/r"; $table = 'new_2'; $dbh->do( "DROP TABLE IF EXISTS $table" ); $dbh->do( "CREATE TABLE $table ( id INT, name CHAR, city CHAR )" ); $sth_new = $dbh->prepare( "INSERT INTO $table( id, name, city ) VALUES ( ?, ?, ?, )" ); $sth_new->execute( 1, 'Smith', 'Greenville' ); $dbh->disconnect();

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  • Cannot overload function

    - by anio
    So I've got a templatized class and I want to overload the behavior of a function when I have specific type, say char. For all other types, let them do their own thing. However, c++ won't let me overload the function. Why can't I overload this function? I really really do not want to do template specialization, because then I've got duplicate the entire class. Here is a toy example demonstrating the problem: http://codepad.org/eTgLG932 The same code posted here for your reading pleasure: #include <iostream> #include <cstdlib> #include <string> struct Bar { std::string blah() { return "blah"; } }; template <typename T> struct Foo { public: std::string doX() { return m_getY(my_t); } private: std::string m_getY(char* p_msg) { return std::string(p_msg); } std::string m_getY(T* p_msg) { return p_msg->blah(); } T my_t; }; int main(int, char**) { Foo<char> x; Foo<Bar> y; std::cout << "x " << x.doX() << std::endl; return EXIT_SUCCESS; } Thank you everyone for your suggestions. Two valid solutions have been presented. I can either specialize the doX method, or specialize m_getY() method. At the end of the day I prefer to keep my specializations private rather than public so I'm accepting Krill's answer.

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  • Appending unique values only in a linked list in C

    - by LuckySlevin
    typedef struct child {int count; char word[100]; inner_list*next;} child; typedef struct parent { char data [100]; inner_list * head; int count; outer_list * next; } parent; void append(child **q,char num[100],int size) { child *temp,*r,*temp2,*temp3; parent *out=NULL; temp = *q; temp2 = *q; temp3 = *q; char *str; if(*q==NULL) { temp = (child *)malloc(sizeof(child)); strcpy(temp->word,num); temp->count =size; temp->next=NULL; *q=temp; } else { temp = *q; while(temp->next !=NULL) { temp=temp->next; } r = (child *)malloc(sizeof(child)); strcpy(r->word,num); r->count = size; r->next=NULL; temp->next=r; } } This is my append function which I use for adding an element to my child list. But my problem is it only should append unique values which are followed by a string. Which means : Inputs : aaa bbb aaa ccc aaa bbb ccc aaa Append should act : For aaa string there should be a list like bbb->ccc(Not bbb->ccc->bbb since bbb is already there if bbb is coming more than one time it should be increase count only.) For bbb string there should be list like aaa->ccc only For ccc string there should be list like aaa only I hope i could make myself clear. Is there any ideas? Please ask for further info.

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  • C: incompatible types in assignment

    - by The.Anti.9
    I'm writing a program to check to see if a port is open in C. One line in particular copies one of the arguments to a char array. However, when I try to compile, it says: error: incompatible types in assignment Heres the code. The error is on the assignment of addr #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <arpa/inet.h> #include <netinet/in.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <netdb.h> #include <stdlib.h> #include <string.h> #include <unistd.h> int main(int argc, char **argv) { u_short port; /* user specified port number */ char addr[1023]; /* will be a copy of the address entered by u */ struct sockaddr_in address; /* the libc network address data structure */ short int sock = -1; /* file descriptor for the network socket */ port = atoi(argv[1]); addr = strncpy(addr, argv[2], 1023); bzero((char *)&address, sizeof(address)); /* init addr struct */ address.sin_addr.s_addr = inet_addr(addr); /* assign the address */ address.sin_port = htons(port); /* translate int2port num */ sock = socket(AF_INET, SOCK_STREAM, 0); if (connect(sock,(struct sockaddr *)&address,sizeof(address)) == 0) { printf("%i is open\n", port); } if (errno == 113) { fprintf(stderr, "Port not open!\n"); } close(sock); return 0; } I'm new to C, so I'm not sure why it would do this.

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  • scanf a byte then print it out?

    - by Sarah
    I've searched around to see if I can find this answer but I can't seem to (please let me know if I'm wrong). I am trying to use scanf to read in a byte, an unsigned int and a char in one .c file and I am trying to access this byte in a different .c file and print it out. (I have already checked to make sure I have included all the appropriate parameters everywhere) But I keep getting errors. The warnings are: database.c: In function ‘addCitizen’: database.c:23:2: warning: format ‘%hhu’ expects argument of type ‘int’, but argument 2 has type ‘byte *’ [-Wformat] database.c:24:2: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 2 has type ‘int *’ [-Wformat] database.c:25:2: warning: format ‘%c’ expects argument of type ‘int’, but argument 2 has type ‘char *’ [-Wformat] where I'm scanf'ing: // Request loop while (count-- != 0) { while (1){ // Get values from the user int error = scanf ("%79s %hhu %u %c", tname, &tdist, &tyear, &tgender); addCitizen(db, tname, &tdist, &tyear, &tgender); where I'm printing: void addCitizen(Database *db, char *tname, byte *tdist, int *tyear, char *tgender){ //needs to find the right place in memory to put this stuff and then put it there printf("\nName is: %79s\n", tname); printf("District is: %hhu\n", tdist); printf("Year of birth is: %u\n", tyear); printf("Gender is:%c\n", tgender); I'm not sure where I'm going wrong?

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  • why malloc+memset slower than calloc?

    - by kingkai
    It's known that calloc differentiates itself with malloc in which it initializes the memory alloted. With calloc, the memory is set to zero. With malloc, the memory is not cleared. So in everyday work, i regard calloc as malloc+memset. Incidentally, for fun, i wrote the following codes for benchmark. The result is confused. Code 1: #include<stdio.h> #include<stdlib.h> #define BLOCK_SIZE 1024*1024*256 int main() { int i=0; char *buf[10]; while(i<10) { buf[i] = (char*)calloc(1,BLOCK_SIZE); i++; } } time ./a.out real 0m0.287s user 0m0.095s sys 0m0.192s Code 2: #include<stdio.h> #include<stdlib.h> #include<string.h> #define BLOCK_SIZE 1024*1024*256 int main() { int i=0; char *buf[10]; while(i<10) { buf[i] = (char*)malloc(BLOCK_SIZE); memset(buf[i],'\0',BLOCK_SIZE); i++; } } time ./a.out real 0m2.693s user 0m0.973s sys 0m1.721s Repalce memset with bzero(buf[i],BLOCK_SIZE) in Code 2 produce the result alike. My Question is that why malloc+memset is so much slower than calloc? How can calloc do that ? Thanks!

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  • ERROR 2019 Linker Error Visual Studio

    - by Corrie Duck
    Hey I hope someone can tell me know to fix this issue I am having i keep getting an error 2019 from Visual studio for the following file. Now most of the functions have been removed so excuse the empty varriables etc. Error error LNK2019: unresolved external symbol "void * __cdecl OpenOneDevice(void *,struct _SP_DEVICE_INTERFACE_DATA *,char *)" (?OpenOneDevice@@YAPAXPAXPAU_SP_DEVICE_INTERFACE_DATA@@PAD@Z) referenced in function _wmain c:\Users\K\documents\visual studio 2010\Projects\test2\test2\test2.obj test2 #include "stdafx.h" #include <windows.h> #include <setupapi.h> SP_DEVICE_INTERFACE_DATA deviceInfoData; HDEVINFO hwDeviceInfo; HANDLE hOut; char *devName; // HANDLE OpenOneDevice(IN HDEVINFO hwDeviceInfo,IN PSP_DEVICE_INTERFACE_DATA DeviceInfoData,IN char *devName); // HANDLE OpenOneDevice(IN HDEVINFO HardwareDeviceInfo,IN PSP_DEVICE_INTERFACE_DATA DeviceInfoData,IN char *devName) { PSP_DEVICE_INTERFACE_DETAIL_DATA functionClassDeviceData = NULL; ULONG predictedLength = 0, requiredLength = 0; HANDLE hOut = INVALID_HANDLE_VALUE; SetupDiGetDeviceInterfaceDetail(HardwareDeviceInfo, DeviceInfoData, NULL, 0, &requiredLength, NULL); predictedLength = requiredLength; functionClassDeviceData = (PSP_DEVICE_INTERFACE_DETAIL_DATA)malloc(predictedLength); if(NULL == functionClassDeviceData) { return hOut; } functionClassDeviceData->cbSize = sizeof (SP_DEVICE_INTERFACE_DETAIL_DATA); if (!SetupDiGetDeviceInterfaceDetail(HardwareDeviceInfo, DeviceInfoData, functionClassDeviceData, predictedLength, &requiredLength, NULL)) { free( functionClassDeviceData ); return hOut; } //strcpy(devName,functionClassDeviceData->DevicePath) ; hOut = CreateFile(functionClassDeviceData->DevicePath, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL); free(functionClassDeviceData); return hOut; } // int _tmain(int argc, _TCHAR* argv[]) { hOut = OpenOneDevice (hwDeviceInfo, &deviceInfoData, devName); if(hOut != INVALID_HANDLE_VALUE) { // error report } return 0; } Been driving me mad for hours. Any help appreciated. SOLVED THANKS TO CHRIS :-) Add #pragma comment (lib, "Setupapi.lib") Thanks

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  • c programming malloc question

    - by user535256
    Hello guys, Just got query regarding c malloc() function. I am read()ing x number of bytes from a file to get lenght of filename, like ' read(file, &namelen, sizeof(unsigned char)); ' . The variable namelen is a type unsigned char and was written into file as that type (1 byte). Now namelen has the lenght of filename ie namelen=8 if file name was 'data.txt', plus extra /0 at end, that working fine. Now I have a structure recording file info, ie filename, filelenght, content size etc. struct fileinfo { char *name; ...... other variable like size etc }; struct fileinfo *files; Question: I want to make that files.name variable the size of namelen ie 8 so I can successfully write the filename into it, like ' files[i].name = malloc(namelen) ' However, I dont want it to be malloc(sizeof(namelen)) as that would make it file.name[1] as the size of its type unsigned char. I want it to be the value thats stored inside variable &namelen ie 8 so file.name[8] so data.txt can be read() from file as 8 bytes and written straight into file.name[8? Is there a way to do this my current code is this and returns 4 not 8 files[i].name = malloc(namelen); //strlen(files[i].name) - returns 4 //perhaps something like malloc(sizeof(&namelen)) but does not work Thanks for any suggestions Have tried suggested suggestions guys, but I now get a segmentation fault error using: printf("\nsizeofnamelen=%x\n",namelen); //gives 8 for data.txt files[i].name = malloc(namelen + 1); read(file, &files[i].name, namelen); int len=strlen(files[i].name); printf("\nnamelen=%d",len); printf("\nname=%s\n",files[i].name); When I try to open() file with that files[i].name variable it wont open so the data does not appear to be getting written inside the read() &files[i].name and strlen() causes segemntation error as well as trying to print the filename

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  • C++ ambiguous template instantiation

    - by aaa
    the following gives me ambiguous template instantiation with nvcc (combination of EDG front-end and g++). Is it really ambiguous, or is compiler wrong? I also post workaround à la boost::enable_if template<typename T> struct disable_if_serial { typedef void type; }; template<> struct disable_if_serial<serial_tag> { }; template<int M, int N, typename T> __device__ //static typename disable_if_serial<T>::type void add_evaluate_polynomial1(double *R, const double (&C)[M][N], double x, const T &thread) { // ... } template<size_t M, size_t N> __device__ static void add_evaluate_polynomial1(double *R, const double (&C)[M][N], double x, const serial_tag&) { for (size_t i = 0; i < M; ++i) add_evaluate_polynomial1(R, C, x, i); } // ambiguous template instantiation here. add_evaluate_polynomial1(R, C, x, serial_tag());

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