Search Results

Search found 7500 results on 300 pages for 'const char'.

Page 11/300 | < Previous Page | 7 8 9 10 11 12 13 14 15 16 17 18  | Next Page >

  • How to 'convert' char to function in C

    - by Tim van Elsloo
    Hi, void someFunction() { char *function = "anotherFunction"; const char *params[] = {"aVal","bVal","cVal"}; // How can I call the *function with the *params? } void anotherFunction(char *aKey, char *bKey, char *cKey) { // Do something with *aKey, *bKey and *cKey; } Does someone know how to call the *function with the *params? Thanks in advance, Tim

    Read the article

  • storing characters in char data type C language

    - by iSight
    Hi, I can store string of few length in char data type. But when it exceeds its capacity what can be the alternative way to store string. I am using char data type. void setString(char* inPoints) { if (strcmp(mPoints, inPoints)!= ZERO) { if (mPoints) { free(mPoints); } mPoints = (char*)malloc((strlen(inPoints) + 1) * sizeof(char)); strcpy(mPoints, inPoints); } }

    Read the article

  • Wrapping a pure virtual method with multiple arguments with Boost.Python

    - by fallino
    Hello, I followed the "official" tutorial and others but still don't manage to expose this pure virtual method (getPeptide) : ms_mascotresults.hpp class ms_mascotresults { public: ms_mascotresults(ms_mascotresfile &resfile, const unsigned int flags, double minProbability, int maxHitsToReport, const char * unigeneIndexFile, const char * singleHit = 0); ... virtual ms_peptide getPeptide(const int q, const int p) const = 0; } ms_mascotresults.cpp #include <boost/python.hpp> using namespace boost::python; #include "msparser.hpp" // which includes "ms_mascotresults.hpp" using namespace matrix_science; #include <iostream> #include <sstream> struct ms_mascotresults_wrapper : ms_mascotresults, wrapper<ms_mascotresults> { ms_peptide getPeptide(const int q, const int p) { this->get_override("getPeptide")(q); this->get_override("getPeptide")(p); } }; BOOST_PYTHON_MODULE(ms_mascotresults) { class_<ms_mascotresults_wrapper, boost::noncopyable>("ms_mascotresults") .def("getPeptide", pure_virtual(&ms_mascotresults::getPeptide) ) ; } Here are the bjam's errors : /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:66: error: cannot declare field ‘boost::python::objects::value_holder<ms_mascotresults_wrapper>::m_held’ to be of abstract type ‘ms_mascotresults_wrapper’ ms_mascotresults.cpp:12: note: because the following virtual functions are pure within ‘ms_mascotresults_wrapper’: ... include/ms_mascotresults.hpp:334: note: virtual matrix_science::ms_peptide matrix_science::ms_mascotresults::getPeptide(int, int) const ms_mascotresults.cpp: In constructor ‘ms_mascotresults_wrapper::ms_mascotresults_wrapper()’: ms_mascotresults.cpp:12: error: no matching function for call to ‘matrix_science::ms_mascotresults::ms_mascotresults()’ include/ms_mascotresults.hpp:284: note: candidates are: matrix_science::ms_mascotresults::ms_mascotresults(matrix_science::ms_mascotresfile&, unsigned int, double, int, const char*, const char*) include/ms_mascotresults.hpp:109: note: matrix_science::ms_mascotresults::ms_mascotresults(const matrix_science::ms_mascotresults&) ... /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp: In constructor ‘boost::python::objects::value_holder<Value>::value_holder(PyObject*) [with Value = ms_mascotresults_wrapper]’: /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:137: note: synthesized method ‘ms_mascotresults_wrapper::ms_mascotresults_wrapper()’ first required here /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:137: error: cannot allocate an object of abstract type ‘ms_mascotresults_wrapper’ ms_mascotresults.cpp:12: note: since type ‘ms_mascotresults_wrapper’ has pure virtual functions So I tried to change the constructor's signature by : BOOST_PYTHON_MODULE(ms_mascotresults) { //class_<ms_mascotresults_wrapper, boost::noncopyable>("ms_mascotresults") class_<ms_mascotresults_wrapper, boost::noncopyable>("ms_mascotresults", init<ms_mascotresfile &, const unsigned int, double, int, const char *,const char *>()) .def("getPeptide", pure_virtual(&ms_mascotresults::getPeptide) ) Giving these errors : /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:66: error: cannot declare field ‘boost::python::objects::value_holder<ms_mascotresults_wrapper>::m_held’ to be of abstract type ‘ms_mascotresults_wrapper’ ms_mascotresults.cpp:12: note: because the following virtual functions are pure within ‘ms_mascotresults_wrapper’: include/ms_mascotresults.hpp:334: note: virtual matrix_science::ms_peptide matrix_science::ms_mascotresults::getPeptide(int, int) const ... ms_mascotresults.cpp:24: instantiated from here /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:137: error: no matching function for call to ‘ms_mascotresults_wrapper::ms_mascotresults_wrapper(matrix_science::ms_mascotresfile&, const unsigned int&, const double&, const int&, const char* const&, const char* const&)’ ms_mascotresults.cpp:12: note: candidates are: ms_mascotresults_wrapper::ms_mascotresults_wrapper(const ms_mascotresults_wrapper&) ms_mascotresults.cpp:12: note: ms_mascotresults_wrapper::ms_mascotresults_wrapper() If I comment the virtual function getPeptide in the .hpp, it builds perfectly with this constructor : class_<ms_mascotresults>("ms_mascotresults", init<ms_mascotresfile &, const unsigned int, double, int, const char *,const char *>() ) So I'm a bit lost...

    Read the article

  • boost::asio buffer impossible to convert parameter from char to const mutable_buffer&

    - by Ekyo777
    visual studio tells me "error C2664: 'boost::asio::mutable_buffer::mutable_buffer(const boost::asio::mutable_buffer&)': impossible to convert parameter 1 from 'char' to 'const boost::asio::mutable_buffer&' at line 163 of consuming_buffers.hpp" I am unsure of why this happen nor how to solve it(otherwise I wouldn't ask this ^^') but I think it could be related to those functions.. even tough I tried them in another project and everything worked fine... but I can hardly find what's different so... here comes code that could be relevant, if anything useful seems to be missing I'll be glad to send it. packets are all instances of this class. class CPacketBase { protected: const unsigned short _packet_type; const size_t _size; char* _data; public: CPacketBase(unsigned short packet_type, size_t size); ~CPacketBase(); size_t get_size(); const unsigned short& get_type(); virtual char* get(); virtual void set(char*); }; this sends a given packet template <typename Handler> void async_write(CPacketBase* packet, Handler handler) { std::string outbuf; outbuf.resize(packet->get_size()); outbuf = packet->get(); boost::asio::async_write( _socket , boost::asio::buffer(outbuf, packet->get_size()) , handler); } this enable reading packets and calls a function that decodes the packet's header(unsigned short) and resize the buffer to send it to another function that reads the real data from the packet template <typename Handler> void async_read(CPacketBase* packet, Handler handler) { void (CTCPConnection::*f)( const boost::system::error_code& , CPacketBase*, boost::tuple<Handler>) = &CTCPConnection::handle_read_header<Handler>; boost::asio::async_read(_socket, _buffer_data , boost::bind( f , this , boost::asio::placeholders::error , packet , boost::make_tuple(handler))); } and this is called by async_read once a packet is received template <typename Handler> void handle_read_header(const boost::system::error_code& error, CPacketBase* packet, boost::tuple<Handler> handler) { if (error) { boost::get<0>(handler)(error); } else { // Figures packet type unsigned short packet_type = *((unsigned short*) _buffer_data.c_str()); // create new packet according to type delete packet; ... // read packet's data _buffer_data.resize(packet->get_size()-2); // minus header size void (CTCPConnection::*f)( const boost::system::error_code& , CPacketBase*, boost::tuple<Handler>) = &CTCPConnection::handle_read_data<Handler>; boost::asio::async_read(_socket, _buffer_data , boost::bind( f , this , boost::asio::placeholders::error , packet , handler)); } }

    Read the article

  • Unable to free const pointers in C

    - by lego69
    How can I free a const char*? I allocated new memory using malloc, and when I'm trying to free it I always receive the error "incompatible pointer type" The code that causes this is something like: char* name="Arnold"; const char* str=(const char*)malloc(strlen(name)+1); free(str); // error here

    Read the article

  • Connecting std::basic_ofstream<unsigned char> to a FIFO. bad_cast exceptions

    - by Mike B
    Using gcc 4.4.3 on Linux 2.6.32, I get bad_cast exceptions when connecting std::basic_ofstream to a FIFO. Stepping though the debugger, I can see that the error is generated at various places in the standard library because the _M_codecvt member of the stream or filebuf object is NULL. Exactly where it happens depends on the order of operations, but it appears to be the same cause in each. So am I doing something fundamentally stupid here? ofstream and ifstream work fine. Is there some reason that you shouldn't attach a stream of anything besides char to a FIFO? Thanks in advance.

    Read the article

  • How to add characters to reach the maximum size of a char[].

    - by Bon_chan
    Hi folks, I have the following part of code : for(int i=0;i<n;i++) { printf("Student %d\n",i+1); printf("Enter name : "); scanf("%s",&(student+i)->name); fflush(stdin); lengthName = strlen((student+i)->name); while(lengthName !='\0') { }} when the length is shorter than 10, it will add hyphens until reaching the maximum size. Ex : John = 6 hyphens will be added I know how to do it in csharp but can't figure it out in c. Could some of you give me some lights please? PS : Oh yes the variable name is char name[10+1] and it a part of the structure called student.

    Read the article

  • EVP_PKEY from char buffer in x509 (PKCS7)

    - by sid
    Hi All, I have a DER certificate from which I am retrieving the Public key in unsigned char buffer as following, is it the right way of getting? pStoredPublicKey = X509_get_pubkey(x509); if(pStoredPublicKey == NULL) { printf(": publicKey is NULL\n"); } if(pStoredPublicKey->type == EVP_PKEY_RSA) { RSA *x = pStoredPublicKey->pkey.rsa; bn = x->n; } else if(pStoredPublicKey->type == EVP_PKEY_DSA) { } else if(pStoredPublicKey->type == EVP_PKEY_EC) { } else { printf(" : Unkown publicKey\n"); } //extracts the bytes from public key & convert into unsigned char buffer buf_len = (size_t) BN_num_bytes (bn); key = (unsigned char *)malloc (buf_len); n = BN_bn2bin (bn, (unsigned char *) key); for (i = 0; i < n; i++) { printf("%02x\n", (unsigned char) key[i]); } keyLen = EVP_PKEY_size(pStoredPublicKey); EVP_PKEY_free(pStoredPublicKey); And, With this unsigned char buffer, How do I get back the EVP_PKEY for RSA? OR Can I use following ???, EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **a, unsigned char **pp, long length); int i2d_PublicKey(EVP_PKEY *a, unsigned char **pp);

    Read the article

  • trie reg exp parse step over char and continue

    - by forest.peterson
    Setup: 1) a string trie database formed from linked nodes and a vector array linking to the next node terminating in a leaf, 2) a recursive regular expression function that if A) char '*' continues down all paths until string length limit is reached, then continues down remaining string paths if valid, and B) char '?' continues down all paths for 1 char and then continues down remaining string paths if valid. 3) after reg expression the candidate strings are measured for edit distance against the 'try' string. Problem: the reg expression works fine for adding chars or swapping ? for a char but if the remaining string has an error then there is not a valid path to a terminating leaf; making the matching function redundant. I tried adding a 'step-over' ? char if the end of the node vector was reached and then followed every path of that node - allowing this step-over only once; resulted in a memory exception; I cannot find logically why it is accessing the vector out of range - bactracking? Questions: 1) how can the regular expression step over an invalid char and continue with the path? 2) why is swapping the 'sticking' char for '?' resulting in an overflow? Function: void Ontology::matchRegExpHelper(nodeT *w, string inWild, Set<string> &matchSet, string out, int level, int pos, int stepover) { if (inWild=="") { matchSet.add(out); } else { if (w->alpha.size() == pos) { int testLength = out.length() + inWild.length(); if (stepover == 0 && matchSet.size() == 0 && out.length() > 8 && testLength == tokenLength) {//candidate generator inWild[0] = '?'; matchRegExpHelper(w, inWild, matchSet, out, level, 0, stepover+1); } else return; //giveup on this path } if (inWild[0] == '?' || (inWild[0] == '*' && (out.length() + inWild.length() ) == level ) ) { //wild matchRegExpHelper(w->alpha[pos].next, inWild.substr(1), matchSet, out+w->alpha[pos].letter, level, 0, stepover);//follow path -> if ontology is full, treat '*' like a '?' } else if (inWild[0] == '*') matchRegExpHelper(w->alpha[pos].next, '*'+inWild.substr(1), matchSet, out+w->alpha[pos].letter, level, 0, stepover); //keep adding chars if (inWild[0] == w->alpha[pos].letter) //follow self matchRegExpHelper(w->alpha[pos].next, inWild.substr(1), matchSet, out+w->alpha[pos].letter, level, 0, stepover); //follow char matchRegExpHelper(w, inWild, matchSet, out, level, pos+1, stepover);//check next path } } Error Message: +str "Attempt to access index 1 in a vector of size 1." std::basic_string<char,std::char_traits<char>,std::allocator<char> > +err {msg="Attempt to access index 1 in a vector of size 1." } ErrorException Note: this function works fine for hundreds of test strings with '*' wilds if the extra stepover gate is not used Semi-Solved: I place a pos < w->alpha.size() condition on each path that calls w->alpha[pos]... - this prevented the backtrack calls from attempting to access the vector with an out of bounds index value. Still have other issues to work out - it loops infinitely adding the ? and backtracking to remove it, then repeat. But, moving forward now. Revised question: why during backtracking is the position index accumulating and/or not deincrementing - so at somepoint it calls w->alpha[pos]... with an invalid position that is either remaining from the next node or somehow incremented pos+1 when passing upward?

    Read the article

  • C++: Trouble with templates (C2064)

    - by Rosarch
    I'm having compiler errors, and I'm not sure why. What am I doing wrong here: Hangman.cpp: set<char> Hangman::incorrectGuesses() { // Hangman line 103 return Utils::findAll_if<char>(guesses.begin(), guesses.end(), &Hangman::isIncorrectGuess); } bool Hangman::isIncorrectGuess(char c) { return correctAnswer.find(c) == string::npos; } Utils.h: namespace Utils { void PrintLine(const string& line, int tabLevel = 0); string getTabs(int tabLevel); template<class result_t, class Predicate> std::set<result_t> findAll_if(typename std::set<result_t>::iterator begin, typename std::set<result_t>::iterator end, Predicate pred) { std::set<result_t> result; // utils line 16 return detail::findAll_if_rec<result_t>(begin, end, pred, result); } } namespace detail { template<class result_t, class Predicate> std::set<result_t> findAll_if_rec(typename std::set<result_t>::iterator begin, typename std::set<result_t>::iterator end, Predicate pred, std::set<result_t> result) { // utils line 25 typename std::set<result_t>::iterator nextResultElem = find_if(begin, end, pred); if (nextResultElem == end) { return result; } result.insert(*nextResultElem); return findAll_if_rec(++nextResultElem, end, pred, result); } } This produces the following compiler errors: algorithm(83): error C2064: term does not evaluate to a function taking 1 arguments algorithm(95) : see reference to function template instantiation '_InIt std::_Find_if<std::_Tree_unchecked_const_iterator<_Mytree>,_Pr>(_InIt,_InIt,_Pr)' being compiled 1> with 1> [ 1> _InIt=std::_Tree_unchecked_const_iterator<std::_Tree_val<std::_Tset_traits<char,std::less<char>,std::allocator<char>,false>>>, 1> _Mytree=std::_Tree_val<std::_Tset_traits<char,std::less<char>,std::allocator<char>,false>>, 1> _Pr=bool (__thiscall Hangman::* )(char) 1> ] utils.h(25) : see reference to function template instantiation '_InIt std::find_if<std::_Tree_const_iterator<_Mytree>,Predicate>(_InIt,_InIt,_Pr)' being compiled 1> with 1> [ 1> _InIt=std::_Tree_const_iterator<std::_Tree_val<std::_Tset_traits<char,std::less<char>,std::allocator<char>,false>>>, 1> _Mytree=std::_Tree_val<std::_Tset_traits<char,std::less<char>,std::allocator<char>,false>>, 1> Predicate=bool (__thiscall Hangman::* )(char), 1> _Pr=bool (__thiscall Hangman::* )(char) 1> ] utils.h(16) : see reference to function template instantiation 'std::set<_Kty> detail::findAll_if_rec<result_t,Predicate>(std::_Tree_const_iterator<_Mytree>,std::_Tree_const_iterator<_Mytree>,Predicate,std::set<_Kty>)' being compiled 1> with 1> [ 1> _Kty=char, 1> result_t=char, 1> Predicate=bool (__thiscall Hangman::* )(char), 1> _Mytree=std::_Tree_val<std::_Tset_traits<char,std::less<char>,std::allocator<char>,false>> 1> ] hangman.cpp(103) : see reference to function template instantiation 'std::set<_Kty> Utils::findAll_if<char,bool(__thiscall Hangman::* )(char)>(std::_Tree_const_iterator<_Mytree>,std::_Tree_const_iterator<_Mytree>,Predicate)' being compiled 1> with 1> [ 1> _Kty=char, 1> _Mytree=std::_Tree_val<std::_Tset_traits<char,std::less<char>,std::allocator<char>,false>>, 1> Predicate=bool (__thiscall Hangman::* )(char) 1> ]

    Read the article

  • How to test whether a char is NOT in a string? (java, junit)

    - by JB
    As title says, im having trouble with my junit tests passing for checking if a character is not in a string and how to check if an empty string doesnt have a character. here is the method i have: public static boolean isThere(String s, char value){ for(int x = 0; x <= s.length(); x++){ if(s.charAt(x) == value){ return true; } else if(s.length() == 0){ return false; } } return false; And here is the junit test: public void testIsThere() { { String sVal = "Jeff George"; boolean hasA = StringMethods.isThere(sVal,'e'); assertTrue(hasA); boolean hasE = StringMethods.isThere(sVal, 'o'); assertTrue(hasE); boolean notIn = StringMethods.isThere(sVal,'b'); assertTrue(notIn); } { String sVal = ""; boolean nothingIn = StringMethods.isThere(sVal,'a'); assertFalse(nothingIn); boolean notIn = StringMethods.isThere(sVal,'b'); assertFalse(notIn); } } Thank you very much, appreciated

    Read the article

  • How can we expose a .NET public const to COM interop

    - by JulienC
    For historical reasons, we need to expose string constants in .NET through COM interface. We managed to expose ENUM but we can't find a way to expose string const. We try the following code : <ComClass(ComClass1.ClassId, ComClass1.InterfaceId, ComClass1.EventsId)> _ Public Class ComClass1 #Region "COM GUIDs" ' These GUIDs provide the COM identity for this class ' and its COM interfaces. If you change them, existing ' clients will no longer be able to access the class. Public Const ClassId As String = "608c6545-977e-4260-a3cf-11545c82906a" Public Const InterfaceId As String = "12b8a6c7-e7f6-4022-becd-2efd8b3a756e" Public Const EventsId As String = "05a2856f-d877-4673-8ea8-20f5a9f268d5" #End Region ' A creatable COM class must have a Public Sub New() ' with no parameters, otherwise, the class will not be ' registered in the COM registry and cannot be created ' via CreateObject. Public Sub New() MyBase.New() End Sub Public Const chaine As String = "TEST" Public Sub Method() End Sub End Class But when we look on the OLE object viewer, we only see the method. See ScreenShot: screenshot of OLE viewer Anyone have an idea ? Thanks,

    Read the article

  • how-to initialize 'const std::vector<T>' like a c array

    - by vscharf
    Is there an elegant way to create and initialize a const std::vector<const T> like const T a[] = { ... } to a fixed (and small) number of values? I need to call a function frequently which expects a vector<T>, but these values will never change in my case. In principle I thought of something like namespace { const std::vector<const T> v(??); } since v won't be used outside of this compilation unit.

    Read the article

  • How to initialize static const char array for ASCII codes [C++]

    - by Janney
    I want to initialize a static const char array with ASCII codes in a constructor, here's my code: class Card { public: Suit(void) { static const char *Suit[4] = {0x03, 0x04, 0x05, 0x06}; // here's the problem static const string *Rank[ 13 ] = {'A', '2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K'}; // and here. } However i got a whole lot of errors stating that 'initializing' : cannot convert from 'char' to 'const std::string *' 'initializing' : cannot convert from 'int' to 'const std::string *' please help me! Thank you so much.

    Read the article

  • Marshalling the value of a char* ANSI string DLL API parameter into a C# string

    - by Brian Biales
    For those who do not mix .NET C# code with legacy DLL's that use char* pointers on a regular basis, the process to convert the strings one way or the other is non-obvious. This is not a comprehensive article on the topic at all, but rather an example of something that took me some time to go find, maybe it will save someone else the time. I am utilizing a third party too that uses a call back function to inform my application of its progress.  This callback includes a pointer that under some circumstances is a pointer to an ANSI character string.  I just need to marshal it into a C# string variable.  Seems pretty simple, yes?  Well, it is, (as are most things, once you know how to do them). The parameter of my callback function is of type IntPtr, which implies it is an integer representation of a pointer.  If I know the pointer is pointing to a simple ANSI string, here is a simple static method to copy it to a C# string: private static string GetStringFromCharStar(IntPtr ptr) {     return System.Runtime.InteropServices.Marshal.PtrToStringAnsi(ptr); } The System.Runtime.InteropServices is where to look any time you are mixing legacy unmanaged code with your .NET application.

    Read the article

  • Return a pointer to a char array in C

    - by snitko
    I've seen a lot of questions on that on StackOverflow, but reading the answers did not clear that up for me, probably because I'm a total newbie in C programming. Here's the code: #include <stdio.h> char* squeeze(char s[], char c); main() { printf("%s", squeeze("hello", 'o')); } char* squeeze(char s[], char c) { int i, j; for(i = j = 0; s[i] != '\0'; i++) if(s[i] != c) s[j++] = s[i]; s[j] = '\0'; return s; } It compiles and I get segmentation fault when I run it. I've read this faq about about returning arrays and tried the 'static' technique that is suggested there, but still could not get the program working. Could anyone point out exactly what's wrong with it and what should I be paying attention in the future?

    Read the article

  • Array of strings and char ** environ variable.

    - by Naruto Uzumaki
    Hello! I want to know how an array of strings is declared? What I do is I declare an array of pointers of pointers to strings. Eg. char *array[]= {"string1","string2","string3"}; I was reading about modifying environment variables in Linux and stumbled upon the pointer char **environ ( http://www.cs.bham.ac.uk/resources/courses/2005/17423/doc/libc/Environment-Access.html#Environment-Access ). char **environ is declared as an array of strings. I think it should be a pointer to a pointer. For eg. char *array[]= {"string1","string2","string3"}; environ = array; Am I doing something wrong? I also read somewhere that char *argv[] = char **argv. How is it possible?

    Read the article

  • C++ error - returning a char array

    - by Yosy
    Consider the following code: char CeaserCrypt(char str[256],int key) { char encrypted[256],encryptedChar; int currentAsci; encrypted[0] = '\0'; for(int i = 0; i < strlen(str); i++) { currentAsci = (int)str[i]; encryptedChar = (char)(currentAsci+key); encrypted[i] = encryptedChar; } return encrypted; } Visual Studio 2010 gives an error because the function returns an array. What should I do? My friend told me to change the signature to void CeaserCrypt(char str[256], char encrypted[256], int key). But I don't think that is correct. How can I get rid of the compile error?

    Read the article

  • Thread-safe initialization of function-local static const objects

    - by sbi
    This question made me question a practice I had been following for years. For thread-safe initialization of function-local static const objects I protect the actual construction of the object, but not the initialization of the function-local reference referring to it. Something like this: namspace { const some_type& create_const_thingy() { lock my_lock(some_mutex); static const some_type the_const_thingy; return the_const_thingy; } } void use_const_thingy() { static const some_type& the_const_thingy = create_const_thingy(); // use the_const_thingy } The idea is that locking takes time, and if the reference is overwritten by several threads, it won't matter. I'd be interested if this is safe enough in practice? safe according to The Rules? (I know, the current standard doesn't even know what "concurrency" is, but what about trampling over an already initialized reference? And do other standards, like POSIX, have something to say that's relevant to this?) For the inquiring minds: Many such function-local static const objects I used are maps which are initialized from const arrays upon first use and used for lookup. For example, I have a few XML parsers where tag name strings are mapped to enum values, so I could later switch over the tags enum values.

    Read the article

  • const pod and std::vector

    - by Baz
    To get this code to compile: std::vector<Foo> factory() { std::vector<Foo> data; return data; } I have to define my POD like this: struct Foo { const int i; const int j; Foo(const int _i, const int _j): i(_i), j(_j) {} Foo(Foo& foo): i(foo.i), j(foo.j){} Foo operator=(Foo& foo) { Foo f(foo.i, foo.j); return f; } }; Is this the correct approach for defining a pod where I'm not interested in changing the pod members after creation? Why am I forced to define a copy constructor and overload the assignment operator? Is this compatible for different platform implementations of std::vector? Is it wrong in your opinion to have const PODS like this? Should I just leave them as non-const?

    Read the article

  • libstdc++ - compiling failing because of tr1/regex

    - by Radek Šimko
    I have these packages installed on my OpenSUSE 11.3: i | libstdc++45 | Standard shared library for C++ | package i | libstdc++45-devel | Contains files and libraries for development | package But when i'm trying to compile this C++ code: #include <stdio.h> #include <tr1/regex> using namespace std; int main() { int test[2]; const tr1::regex pattern(".*"); test[0] = 1; if (tr1::regex_match("anything", pattern) == false) { printf("Pattern does not match.\n"); } return 0; } using g++ -pedantic -g -O1 -o ./main.o ./main.cpp It outputs this errors: ./main.cpp: In function ‘int main()’: ./main.cpp:13:43: error: ‘printf’ was not declared in this scope radek@mypc:~> nano main.cpp radek@mypc:~> g++ -pedantic -g -O1 -o ./main.o ./main.cpp /tmp/cc0g3GUE.o: In function `basic_regex': /usr/include/c++/4.5/tr1_impl/regex:771: undefined reference to `std::tr1::basic_regex<char, std::tr1::regex_traits<char> >::_M_compile()' /tmp/cc0g3GUE.o: In function `bool std::tr1::regex_match<char const*, char, std::tr1::regex_traits<char> >(char const*, char const*, std::tr1::basic_regex<char, std::tr1::regex_traits<char> > const&, std::bitset<11u>)': /usr/include/c++/4.5/tr1_impl/regex:2144: undefined reference to `bool std::tr1::regex_match<char const*, std::allocator<std::tr1::sub_match<char const*> >, char, std::tr1::regex_traits<char> >(char const*, char const*, std::tr1::match_results<char const*, std::allocator<std::tr1::sub_match<char const*> > >&, std::tr1::basic_regex<char, std::tr1::regex_traits<char> > const&, std::bitset<11u>)' collect2: ld returned 1 exit status What packages should i (un)install to make the code work on my PC?

    Read the article

  • Atmospheric Scattering

    - by Lawrence Kok
    I'm trying to implement atmospheric scattering based on Sean O`Neil algorithm that was published in GPU Gems 2. But I have some trouble getting the shader to work. My latest attempts resulted in: http://img253.imageshack.us/g/scattering01.png/ I've downloaded sample code of O`Neil from: http://http.download.nvidia.com/developer/GPU_Gems_2/CD/Index.html. Made minor adjustments to the shader 'SkyFromAtmosphere' that would allow it to run in AMD RenderMonkey. In the images it is see-able a form of banding occurs, getting an blueish tone. However it is only applied to one half of the sphere, the other half is completely black. Also the banding appears to occur at Zenith instead of Horizon, and for a reason I managed to get pac-man shape. I would appreciate it if somebody could show me what I'm doing wrong. Vertex Shader: uniform mat4 matView; uniform vec4 view_position; uniform vec3 v3LightPos; const int nSamples = 3; const float fSamples = 3.0; const vec3 Wavelength = vec3(0.650,0.570,0.475); const vec3 v3InvWavelength = 1.0f / vec3( Wavelength.x * Wavelength.x * Wavelength.x * Wavelength.x, Wavelength.y * Wavelength.y * Wavelength.y * Wavelength.y, Wavelength.z * Wavelength.z * Wavelength.z * Wavelength.z); const float fInnerRadius = 10; const float fOuterRadius = fInnerRadius * 1.025; const float fInnerRadius2 = fInnerRadius * fInnerRadius; const float fOuterRadius2 = fOuterRadius * fOuterRadius; const float fScale = 1.0 / (fOuterRadius - fInnerRadius); const float fScaleDepth = 0.25; const float fScaleOverScaleDepth = fScale / fScaleDepth; const vec3 v3CameraPos = vec3(0.0, fInnerRadius * 1.015, 0.0); const float fCameraHeight = length(v3CameraPos); const float fCameraHeight2 = fCameraHeight * fCameraHeight; const float fm_ESun = 150.0; const float fm_Kr = 0.0025; const float fm_Km = 0.0010; const float fKrESun = fm_Kr * fm_ESun; const float fKmESun = fm_Km * fm_ESun; const float fKr4PI = fm_Kr * 4 * 3.141592653; const float fKm4PI = fm_Km * 4 * 3.141592653; varying vec3 v3Direction; varying vec4 c0, c1; float scale(float fCos) { float x = 1.0 - fCos; return fScaleDepth * exp(-0.00287 + x*(0.459 + x*(3.83 + x*(-6.80 + x*5.25)))); } void main( void ) { // Get the ray from the camera to the vertex, and its length (which is the far point of the ray passing through the atmosphere) vec3 v3FrontColor = vec3(0.0, 0.0, 0.0); vec3 v3Pos = normalize(gl_Vertex.xyz) * fOuterRadius; vec3 v3Ray = v3CameraPos - v3Pos; float fFar = length(v3Ray); v3Ray = normalize(v3Ray); // Calculate the ray's starting position, then calculate its scattering offset vec3 v3Start = v3CameraPos; float fHeight = length(v3Start); float fDepth = exp(fScaleOverScaleDepth * (fInnerRadius - fCameraHeight)); float fStartAngle = dot(v3Ray, v3Start) / fHeight; float fStartOffset = fDepth*scale(fStartAngle); // Initialize the scattering loop variables float fSampleLength = fFar / fSamples; float fScaledLength = fSampleLength * fScale; vec3 v3SampleRay = v3Ray * fSampleLength; vec3 v3SamplePoint = v3Start + v3SampleRay * 0.5; // Now loop through the sample rays for(int i=0; i<nSamples; i++) { float fHeight = length(v3SamplePoint); float fDepth = exp(fScaleOverScaleDepth * (fInnerRadius - fHeight)); float fLightAngle = dot(normalize(v3LightPos), v3SamplePoint) / fHeight; float fCameraAngle = dot(normalize(v3Ray), v3SamplePoint) / fHeight; float fScatter = (-fStartOffset + fDepth*( scale(fLightAngle) - scale(fCameraAngle)))/* 0.25f*/; vec3 v3Attenuate = exp(-fScatter * (v3InvWavelength * fKr4PI + fKm4PI)); v3FrontColor += v3Attenuate * (fDepth * fScaledLength); v3SamplePoint += v3SampleRay; } // Finally, scale the Mie and Rayleigh colors and set up the varying variables for the pixel shader vec4 newPos = vec4( (gl_Vertex.xyz + view_position.xyz), 1.0); gl_Position = gl_ModelViewProjectionMatrix * vec4(newPos.xyz, 1.0); gl_Position.z = gl_Position.w * 0.99999; c1 = vec4(v3FrontColor * fKmESun, 1.0); c0 = vec4(v3FrontColor * (v3InvWavelength * fKrESun), 1.0); v3Direction = v3CameraPos - v3Pos; } Fragment Shader: uniform vec3 v3LightPos; varying vec3 v3Direction; varying vec4 c0; varying vec4 c1; const float g =-0.90f; const float g2 = g * g; const float Exposure =2; void main(void){ float fCos = dot(normalize(v3LightPos), v3Direction) / length(v3Direction); float fMiePhase = 1.5 * ((1.0 - g2) / (2.0 + g2)) * (1.0 + fCos*fCos) / pow(1.0 + g2 - 2.0*g*fCos, 1.5); gl_FragColor = c0 + fMiePhase * c1; gl_FragColor.a = 1.0; }

    Read the article

< Previous Page | 7 8 9 10 11 12 13 14 15 16 17 18  | Next Page >