Search Results

Search found 3389 results on 136 pages for 'const'.

Page 65/136 | < Previous Page | 61 62 63 64 65 66 67 68 69 70 71 72  | Next Page >

  • How can I create a properly sizing QWebView?

    - by chacham15
    I want to make a QWebView appear expanding to the width and height so that ideally it will have no scroll bars. Some websites may have fixed widths that wont allow this, but I am not concerned with those. In any case, I cannot do as I wish because QWebView implements sizeHint as follows: QSize QWebView::sizeHint() const { return QSize(800, 600); // ####... } This is incorrect on a number of levels. 1. It doesnt at all take into account the size of the actual web page. 2. It doesnt take into account that the height and width are related to each other. (To prove #2 think about text in web pages that wraps to the next line.) As a simple fix I tried to do (where QResizingWebView extends QWebView): QSize QResizingWebView::sizeHint() const{ return this-page()-mainFrame()-contentsSize(); } While this is closer to the result, it also has 2 flaws. 1. It doesnt take into account the relation between the displayed width/height. 2. this->page()->mainFrame()->contentsSize() is inaccurate from what I can tell from my preliminary testing (it has returned heights larger than it should under many cases, although this may be related to #1). Does anyone have any tips to fix this?

    Read the article

  • Binary files printing and desired precision

    - by yCalleecharan
    Hi, I'm printing a variable say z1 which is a 1-D array containing floating point numbers to a text file so that I can import into Matlab or GNUPlot for plotting. I've heard that binary files (.dat) are smaller than .txt files. The definition that I currently use for printing to a .txt file is: void create_out_file(const char *file_name, const long double *z1, size_t z_size){ FILE *out; size_t i; if((out = _fsopen(file_name, "w+", _SH_DENYWR)) == NULL){ fprintf(stderr, "***> Open error on output file %s", file_name); exit(-1); } for(i = 0; i < z_size; i++) fprintf(out, "%.16Le\n", z1[i]); fclose(out); } I have three questions: Are binary files really more compact than text files?; If yes, I would like to know how to modify the above code so that I can print the values of the array z1 to a binary file. I've read that fprintf has to be replaced with fwrite. My output file say dodo.dat should contain the values of array z1 with one floating number per line. I have %.16Le up in my code but I think that %.15Le is right as I have 15 precision digits with long double. I have put a dot (.) in the width position as I believe that this allows expansion to an arbitrary field to hold the desired number. Am I right? As an example with %.16Le, I can have an output like 1.0047914240730432e-002 which gives me 16 precision digits and the width of the field has the right width to display the number correctly. Is placing a dot (.) in the width position instead of a width value a good practice? Thanks a lot...

    Read the article

  • Compile Assembly Output generated by VC++?

    - by SDD
    I have a simple hello world C program and compile it with /FA. As a consequence, the compiler also generates the corresponding assembly listing. Now I want to use masm/link to assemble an executable from the generated .asm listing. The following command line yields 3 linker errors: \masm32\bin\ml /I"C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\include" /c /coff asm_test.asm \masm32\bin\link /SUBSYSTEM:CONSOLE /LIBPATH:"C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\lib" asm_test.obj indicating that the C-runtime functions were not linked to the object files produced earlier: asm_test.obj : error LNK2001: unresolved external symbol @__security_check_cookie@4 asm_test.obj : error LNK2001: unresolved external symbol _printf LINK : error LNK2001: unresolved external symbol _wmainCRTStartup asm_test.exe : fatal error LNK1120: 3 unresolved externals Here is the generated assembly listing ; Listing generated by Microsoft (R) Optimizing Compiler Version 15.00.30729.01 TITLE c:\asm_test\asm_test\asm_test.cpp .686P .XMM include listing.inc .model flat INCLUDELIB OLDNAMES PUBLIC ??_C@_0O@OBPALAEI@hello?5world?$CB?6?$AA@ ; `string' EXTRN @__security_check_cookie@4:PROC EXTRN _printf:PROC ; COMDAT ??_C@_0O@OBPALAEI@hello?5world?$CB?6?$AA@ CONST SEGMENT ??_C@_0O@OBPALAEI@hello?5world?$CB?6?$AA@ DB 'hello world!', 0aH, 00H ; `string' CONST ENDS PUBLIC _wmain ; Function compile flags: /Ogtpy ; COMDAT _wmain _TEXT SEGMENT _argc$ = 8 ; size = 4 _argv$ = 12 ; size = 4 _wmain PROC ; COMDAT ; File c:\users\octon\desktop\asm_test\asm_test\asm_test.cpp ; Line 21 push OFFSET ??_C@_0O@OBPALAEI@hello?5world?$CB?6?$AA@ call _printf add esp, 4 ; Line 22 xor eax, eax ; Line 23 ret 0 _wmain ENDP _TEXT ENDS END I am using the latest masm32 version (6.14.8444).

    Read the article

  • How to asynchronously read to std::string using Boost::asio?

    - by SpyBot
    Hello. I'm learning Boost::asio and all that async stuff. How can I asynchronously read to variable user_ of type std::string? Boost::asio::buffer(user_) works only with async_write(), but not with async_read(). It works with vector, so what is the reason for it not to work with string? Is there another way to do that besides declaring char user_[max_len] and using Boost::asio::buffer(user_, max_len)? Also, what's the point of inheriting from boost::enable_shared_from_this<Connection> and using shared_from_this() instead of this in async_read() and async_write()? I've seen that a lot in the examples. Here is a part of my code: class Connection { public: Connection(tcp::acceptor &acceptor) : acceptor_(acceptor), socket_(acceptor.get_io_service(), tcp::v4()) { } void start() { acceptor_.get_io_service().post( boost::bind(&Connection::start_accept, this)); } private: void start_accept() { acceptor_.async_accept(socket_, boost::bind(&Connection::handle_accept, this, placeholders::error)); } void handle_accept(const boost::system::error_code& err) { if (err) { disconnect(); } else { async_read(socket_, boost::asio::buffer(user_), boost::bind(&Connection::handle_user_read, this, placeholders::error, placeholders::bytes_transferred)); } } void handle_user_read(const boost::system::error_code& err, std::size_t bytes_transferred) { if ( err or (bytes_transferred != sizeof(user_)) ) { disconnect(); } else { ... } } ... void disconnect() { socket_.shutdown(tcp::socket::shutdown_both); socket_.close(); socket_.open(tcp::v4()); start_accept(); } tcp::acceptor &acceptor_; tcp::socket socket_; std::string user_; std::string pass_; ... };

    Read the article

  • function pointers callbacks C

    - by robUK
    Hello, I have started to review callbacks. I found this link: http://stackoverflow.com/questions/142789/what-is-a-callback-in-c-and-how-are-they-implemented which has a good example of callback which is very similar to what we use at work. However, I have tried to get it to work, but I have many errors. #include <stdio.h> /* Is the actual function pointer? */ typedef void (*event_cb_t)(const struct event *evt, void *user_data); struct event_cb { event_cb_t cb; void *data; }; int event_cb_register(event_ct_t cb, void *user_data); static void my_event_cb(const struct event *evt, void *data) { /* do some stuff */ } int main(void) { event_cb_register(my_event_cb, &my_custom_data); struct event_cb *callback; callback->cb(event, callback->data); return 0; } I know that callback use function pointers to store an address of a function. But there is a few things that I find I don't understand. That is what is meet by "registering the callback" and "event dispatcher"? Many thanks for any advice,

    Read the article

  • Compile time float packing/punning

    - by detly
    I'm writing C for the PIC32MX, compiled with Microchip's PIC32 C compiler (based on GCC 3.4). My problem is this: I have some reprogrammable numeric data that is stored either on EEPROM or in the program flash of the chip. This means that when I want to store a float, I have to do some type punning: typedef union { int intval; float floatval; } IntFloat; unsigned int float_as_int(float fval) { IntFloat intf; intf.floatval = fval; return intf.intval; } // Stores an int of data in whatever storage we're using void StoreInt(unsigned int data, unsigned int address); void StoreFPVal(float data, unsigned int address) { StoreInt(float_as_int(data), address); } I also include default values as an array of compile time constants. For (unsigned) integer values this is trivial, I just use the integer literal. For floats, though, I have to use this Python snippet to convert them to their word representation to include them in the array: import struct hex(struct.unpack("I", struct.pack("f", float_value))[0]) ...and so my array of defaults has these indecipherable values like: const unsigned int DEFAULTS[] = { 0x00000001, // Some default integer value, 1 0x3C83126F, // Some default float value, 0.005 } (These actually take the form of X macro constructs, but that doesn't make a difference here.) Commenting is nice, but is there a better way? It's be great to be able to do something like: const unsigned int DEFAULTS[] = { 0x00000001, // Some default integer value, 1 COMPILE_TIME_CONVERT(0.005), // Some default float value, 0.005 } ...but I'm completely at a loss, and I don't even know if such a thing is possible. Notes Obviously "no, it isn't possible" is an acceptable answer if true. I'm not overly concerned about portability, so implementation defined behaviour is fine, undefined behaviour is not (I have the IDB appendix sitting in front of me). As fas as I'm aware, this needs to be a compile time conversion, since DEFAULTS is in the global scope. Please correct me if I'm wrong about this.

    Read the article

  • Crash generated during destruction of hash_map

    - by Alien01
    I am using hash_map in application as typedef hash_map<DWORD,CComPtr<IInterfaceXX>> MapDword2Interface; In main application I am using static instance of this map static MapDword2Interface m_mapDword2Interface; I have got one crash dump from one of the client machines which point to the crash in clearing this map I opened that crash dump and here is assembly during debugging > call std::list<std::pair<unsigned long const ,ATL::CComPtr<IInterfaceXX> >,std::allocator<std::pair<unsigned long const ,ATL::CComPtr<IInterfaceXX> > > >::clear > mov eax,dword ptr [CMainApp::m_mapDword2Interface+8 (49XXXXX)] Here is code where crash dump is pointing. Below code is from stl:list file void clear() { // erase all #if _HAS_ITERATOR_DEBUGGING this->_Orphan_ptr(*this, 0); #endif /* _HAS_ITERATOR_DEBUGGING */ _Nodeptr _Pnext; _Nodeptr _Pnode = _Nextnode(_Myhead); _Nextnode(_Myhead) = _Myhead; _Prevnode(_Myhead) = _Myhead; _Mysize = 0; for (; _Pnode != _Myhead; _Pnode = _Pnext) { // delete an element _Pnext = _Nextnode(_Pnode); this->_Alnod.destroy(_Pnode); this->_Alnod.deallocate(_Pnode, 1); } } Crash is pointing to the this->_Alnod.destroy(_Pnode); statement in above code. I am not able to guess it, what could be reason. Any ideas??? How can I make sure, even is there is something wrong with the map , it should not crash?

    Read the article

  • Best way to detect similar email addresses?

    - by Chris
    I have a list of ~20,000 email addresses, some of which I know to be fraudulent attempts to get around a "1 per e-mail" limit. ([email protected], [email protected], [email protected], etc...). I want to find similar email addresses for evaluation. Currently I'm using a levenshtein algorithm to check each e-mail against the others in the list and report any with an edit distance of less than 2. However, this is painstakingly slow. Is there a more efficient approach? The test code I'm using now is: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Threading; namespace LevenshteinAnalyzer { class Program { const string INPUT_FILE = @"C:\Input.txt"; const string OUTPUT_FILE = @"C:\Output.txt"; static void Main(string[] args) { var inputWords = File.ReadAllLines(INPUT_FILE); var outputWords = new SortedSet<string>(); for (var i = 0; i < inputWords.Length; i++) { if (i % 100 == 0) Console.WriteLine("Processing record #" + i); var word1 = inputWords[i].ToLower(); for (var n = i + 1; n < inputWords.Length; n++) { if (i == n) continue; var word2 = inputWords[n].ToLower(); if (word1 == word2) continue; if (outputWords.Contains(word1)) continue; if (outputWords.Contains(word2)) continue; var distance = LevenshteinAlgorithm.Compute(word1, word2); if (distance <= 2) { outputWords.Add(word1); outputWords.Add(word2); } } } File.WriteAllLines(OUTPUT_FILE, outputWords.ToArray()); Console.WriteLine("Found {0} words", outputWords.Count); } } }

    Read the article

  • What makes this "declarator invalid"? C++

    - by nieldw
    I have Vertex template in vertex.h. From my graph.h: 20 template<class edgeDecor, class vertexDecor, bool dir> 21 class Vertex; which I use in my Graph template. I've used the Vertex template successfully throughout my Graph, return pointers to Vertices, etc. Now for the first time I am trying to declare and instantiate a Vertex object, and gcc is telling me that my 'declarator' is 'invalid'. How can this be? 81 template<class edgeDecor, class vertexDecor, bool dir> 82 Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const 83 { 84 /* Construct new Graph with apropriate decorators */ 85 Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); 86 span.E.reserve(this->E.size()); 87 88 typename Vertex<edgeDecor,int,dir> v = new Vertex(INT_MAX); 89 span.V = new vector<Vertex<edgeDecor,int,dir> >(this->V.size,v); 90 }; And gcc is saying: graph.h: In member function ‘Graph<edgeDecor, int, dir> Graph<edgeDecor, vertexDecor, dir>::Dijkstra(Vertex<edgeDecor, vertexDecor, dir>, bool) const’: graph.h:88: error: invalid declarator before ‘v’ graph.h:89: error: ‘v’ was not declared in this scope I know this is probably another noob question, but I'll appreciate any help.

    Read the article

  • visual studio macro - copy a definition or declaration from/to .h to/from .cpp

    - by Michael
    Is it possible to do a macro that copies a definition of a function to a declaration, and also the opposite? For instance class Foo { Foo(int aParameter, int aDefaultParameter = 0); int someMethod(char aCharacter) const; }; from the .h file would be: Foo::Foo(int aParameter, int aDefaultParameter){ // } int Foo::someMethod(char aCharacter) const { return 0; } in the .cpp file. The opposite wouldn't work with the default value, but it would still be cool if it copied the declaration into the class in the header file. Also if it could return a default value as in someMethod (based on the return value from the declaration). Personally I tried to do macrocoding some year ago (I think it was around 2005) but the tutorials and documentation of macros was thin (or I hadn't searched enough). I ended up going through the examples that they had in the IDE but gave up when I figured it would take too long to learn. I would however like to give it a try again. So if there are anyone with knowledge of good tutorials or documentation that aims at Visual Studio .Net (and maybe also covers the above problem) I would probably accept that as an answer as well :)

    Read the article

  • implement SIMD in C++

    - by Hristo
    I'm working on a bit of code and I'm trying to optimize it as much as possible, basically get it running under a certain time limit. The following makes the call... static affinity_partitioner ap; parallel_for(blocked_range<size_t>(0, T), LoopBody(score), ap); ... and the following is what is executed. void operator()(const blocked_range<size_t> &r) const { int temp; int i; int j; size_t k; size_t begin = r.begin(); size_t end = r.end(); for(k = begin; k != end; ++k) { // for each trainee temp = 0; for(i = 0; i < N; ++i) { // for each sample int trr = trRating[k][i]; int ei = E[i]; for(j = 0; j < ei; ++j) { // for each expert temp += delta(i, trr, exRating[j][i]); } } myscore[k] = temp; } } I'm using Intel's TBB to optimize this. But I've also been reading about SIMD and SSE2 and things along that nature. So my question is, how do I store the variables (i,j,k) in registers so that they can be accessed faster by the CPU? I think the answer has to do with implementing SSE2 or some variation of it, but I have no idea how to do that. Any ideas? Thanks, Hristo

    Read the article

  • Why MSMQ won't send a space character?

    - by cyclotis04
    I'm exploring MSMQ services, and I wrote a simple console client-server application that sends each of the client's keystrokes to the server. Whenever hit a control character (DEL, ESC, INS, etc) the server understandably throws an error. However, whenever I type a space character, the server receives the packet but doesn't throw an error and doesn't display the space. Server: namespace QIM { class Program { const string QUEUE = @".\Private$\qim"; static MessageQueue _mq; static readonly object _mqLock = new object(); static XmlSerializer xs; static void Main(string[] args) { lock (_mqLock) { if (!MessageQueue.Exists(QUEUE)) _mq = MessageQueue.Create(QUEUE); else _mq = new MessageQueue(QUEUE); } xs = new XmlSerializer(typeof(string)); _mq.BeginReceive(new TimeSpan(0, 1, 0), new object(), OnReceive); while (Console.ReadKey().Key != ConsoleKey.Escape) { } } static void OnReceive(IAsyncResult result) { Message msg; lock (_mqLock) { try { msg = _mq.EndReceive(result); Console.Write("."); Console.Write(xs.Deserialize(msg.BodyStream)); } catch (Exception ex) { Console.Write(ex); } } _mq.BeginReceive(new TimeSpan(0, 1, 0), new object(), OnReceive); } } } Client: namespace QIM_Client { class Program { const string QUEUE = @".\Private$\qim"; static MessageQueue _mq; static void Main(string[] args) { if (!MessageQueue.Exists(QUEUE)) _mq = MessageQueue.Create(QUEUE); else _mq = new MessageQueue(QUEUE); ConsoleKeyInfo key = new ConsoleKeyInfo(); while (key.Key != ConsoleKey.Escape) { key = Console.ReadKey(); _mq.Send(key.KeyChar.ToString()); } } } } Client Input: Testing, Testing... Server Output: .T.e.s.t.i.n.g.,..T.e.s.t.i.n.g...... You'll notice that the space character sends a message, but the character isn't displayed.

    Read the article

  • No output got after execution.

    - by wilson88
    I am still stuck with getting output for a copied vector. Probably something am not doing right. I get no output. void Auctioneer::accept_bids(const BidList& bid){ BidList list; BidList list2; BidList::const_iterator iter; copy (list.begin(),list.end(), back_inserter(list2)); for(iter=list2.begin(); iter != list2.end(); iter++) { const Bid& bid = *iter; // Get a reference to the Bid object that the iterator points to cout << "Bid id : " << bid.bidId << endl; cout << "Trd id : " << bid.trdId << endl; cout << "Quantity: " << bid.qty << endl; cout << "Price : " << bid.price << endl; cout << "Type : " << bid.type << endl; } }

    Read the article

  • what are all the Optimize tricks that you know for asp.net code ?

    - by Aristos
    After some time of many code programming on asp.net, I discover the very big speed different between string and StringBuilder. I know that is very common and known but I just mention it for start. The second think that I have found to speed up the code, is to use the const, and not the static, for declare my configuration constants value (especial the strings). With the const, the compiler not create new object, but just place the value, on the point that you have ask it, but with the static declaration, is create a new memory object and keep its on the memory. My third trick, is when I search for string, I use hash values, and not the string itself. For example, if I need a List<string SomeValues, and place inside strings that I need to search them, I prefer to use List<int SomeHashValue, and I use the hash value to locate the strings. My forth thought that I was wandering, is if is better to place big strings in one line, or separate them in different lines with the + symbol to be more easy to read out. I make some tests and see that the compiler make a good job is some split the string, in many lines, using the + symbol. What other tricks/tips do you know and use on your programming to make it run faster, and maybe use less memory. Well I know, that some times, to make something run faster, you need more memory, more cache. My priority is on speed. Because Speed Counts.

    Read the article

  • How to give a textbox a fixed width of 17,5 cm?

    - by Natrium
    I have an application with a textbox, and the width of the textbox on the screen must always be 17,5 centimeters on the screen of the user. This is what I tried so far: const double centimeter = 17.5; // the width I need const double inches = centimeter * 0.393700787; // convert centimeter to inches float dpi = GetDpiX(); // get the dpi. 96 in my case. var pixels = dpi*inches; // this should give me the amount of pixels textbox1.Width = Convert.ToInt32(pixels); // set it. Done. private float GetDpiX() { floar returnValue; Graphics graphics = CreateGraphics(); returnValue = graphics.DpiX; graphics.Dispose(); // don’t forget to release the unnecessary resources return returnValue; } But this gives me different sizes with different resolutions. It gives me 13 cm with 1680 x 1050 and 19,5 cm with 1024 x 768. What am I doing wrong?

    Read the article

  • QT QSslError being signaled with the error code set to NoError

    - by Nantucket
    My Problem I compiled OpenSSL into QT to enable OpenSSL support. Everything appeared to go correctly in the compile. However, when I try to use the official HTTP example application that can be found here, everytime I try to download an https page, it will signal two QSslError, each with contents NoError. The types of QSslErrors, including NoError, are documented here, poorly. There is no explanation on why they even included an error type called NoError, or what it means. Bizarrely, the NoError error code seems to be true, as it downloads the remote https document perfectly even while signaling the error. Does anyone have any idea what this means and what could possibly be causing it? Optional Background Reading Here is the relevant part of the code from the example app (this is connected to the network connection's sslErrors signal by the constructor): void HttpWindow::sslErrors(QNetworkReply*,const QList<QSslError> &errors) { QString errorString; foreach (const QSslError &error, errors) { if (!errorString.isEmpty()) errorString += ", "; errorString += error.errorString(); } if (QMessageBox::warning(this, tr("HTTP"), tr("One or more SSL errors has occurred: %1").arg(errorString), QMessageBox::Ignore | QMessageBox::Abort) == QMessageBox::Ignore) { reply->ignoreSslErrors(); } } I have tried the old version of this example, and it produced the same result. I have tried OpenSSL 1.0.0a and 0.9.8o. I have tried tried compiling OpenSSL myself, I have tried using pre-compiled versions of OpenSSL from the net. All produce the same result. If this were my first time using QT with SSL, I would almost think this is the intended result (even though their example application is popping up error warning message windows), if not for the fact that last time I played with QT, using what would now be an old version of QT with an old version of SSL, I distinctly remember everything working fine with no error windows. My system is running Windows 7 x64.

    Read the article

  • Detecting Inheritence during compile time

    - by Jagannath
    I am unable to figure out why this code is returning false. I had the first version of partial specialization. It did not work, I tried with the second version. It did not work either. UPDATE: I wanted to check if "Derived" is publicly derived from "Base". template<class TBase, class TDerived> struct IsDerived { public: enum { isDerived = false }; }; template<class TBase> struct IsDerived<TBase, TBase> { public: enum { isDerived = true }; }; template<class TBase> struct IsDerived<TBase&, TBase&> { public: enum { isDerived = true }; }; int main() { cout << ((IsDerived<Base&, Derived&>::isDerived) ? "true" : "false") << endl; cout << ((IsDerived<const Derived*, const Base*>::isDerived) ? "true" : "false") << endl; }

    Read the article

  • Returning object from function

    - by brainydexter
    I am really confused now on how and which method to use to return object from a function. I want some feedback on the solutions for the given requirements. Scenario A: The returned object is to be stored in a variable which need not be modified during its lifetime. Thus, const Foo SomeClass::GetFoo() { return Foo(); } invoked as: someMethod() { const Foo& l_Foo = someClassPInstance->GetFoo(); //... } Scneraio B: The returned object is to be stored in a variable which will be modified during its lifetime. Thus, void SomeClass::GetFoo(Foo& a_Foo_ref) { a_Foo_ref = Foo(); } invoked as: someMethod() { Foo l_Foo; someClassPInstance-GetFoo(l_Foo); //... } I have one question here: Lets say that Foo cannot have a default constructor. Then how would you deal with that in this situation, since we cant write this anymore: Foo l_Foo Scenario C: Foo SomeClass::GetFoo() { return Foo(); } invoked as: someMethod() { Foo l_Foo = someClassPInstance->GetFoo(); //... } I think this is not the recommended approach since it would incur constructing extra temporaries. What do you think ? Also, do you recommend a better way to handle this instead ?

    Read the article

  • C++ return a "NULL" object if search result not found

    - by aduric
    I'm pretty new to C++ so I tend to design with a lot of Java-isms while I'm learning. Anyway, in Java, if I had class with a 'search' method that would return an object T from a Collection< T that matched a specific parameter, I would return that object and if the object was not found in the collection, I would return a NULL. Then in my calling function I would just check if(T != NULL) { ... } In C++, I'm finding out that I can't return a NULL if the object doesn't exist. I just want to return an 'indicator' of type T that notifies the calling function that no object has been found. I don't want to throw an exception because it's not really an exceptional circumstance. class Node { .... Attr& getAttribute(const string& attribute_name) const { //search collection //if found at i return attributes[i]; //if not found return NULL; } private: vector<Attr> attributes; }

    Read the article

  • How to call a function from another class file

    - by Guy Parker
    I am very familiar with writing VB based applications but am new to Xcode (and Objective C). I have gone through numerous tutorials on the web and understand the basics and how to interact with Interface Builder etc. However, I am really struggling with some basic concepts of the C language and would be grateful for any help you can offer. Heres my problem… I have a simple iphone app which has a view controller (FirstViewController) and a subview (SecondViewController) with associated header and class files. In the FirstViewController.m have a function defined @implementation FirstViewController (void) writeToServer:(const uint8_t ) buf { [oStream write:buf maxLength:strlen((char)buf)]; } It doesn't really matter what the function is. I want to use this function in my SecondViewController, so in SecondViewController.m I import FirstViewController.h import "SecondViewController.h" import "FirstViewController.h" @implementation SecondViewController -(IBAction) SetButton: (id) sender { NSString *s = [@"Fill:" stringByAppendingString: FillLevelValue.text]; NSString *strToSend = [s stringByAppendingString: @":"]; const uint8_t *str = (uint8_t *) [strToSend cStringUsingEncoding:NSASCIIStringEncoding]; FillLevelValue.text = strToSend; [FirstViewController writeToServer:str]; } This last line is where my problem is. XCode tells me that FirstViewController may not respond to writeToServer. And when I try to run the application it crashes when this function is called. I guess I don't fully understand how to share functions and more importantly, the relationship between classes. In an ideal world I would create a global class to place my functions in and call them as required. Any advice gratefully received.

    Read the article

  • Unhandled Exception error message

    - by Joshua Green
    Does anyone know why including a term such as: t = PL_new_term_ref(); would cause an Unhandled Exception error message: 0xC0000005: Access violation reading location 0x0000000c. (Visual Studio 2008) I have a header file: class UserTaskProlog : public ArAction { public: UserTaskProlog( const char* name = " sth " ); ~UserTaskProlog( ); AREXPORT virtual ArActionDesired *fire( ArActionDesired currentDesired ); private: term_t t; }; and a cpp file: UserTaskProlog::UserTaskProlog( const char* name ) : ArAction( name, " sth " ) { char** argv; argv[ 0 ] = "libpl.dll"; PL_initialise( 1, argv ); PlCall( "consult( 'myProg.pl' )" ); } UserTaskProlog::~UserTaskProlog( ) { } ArActionDesired *UserTaskProlog::fire( ArActionDesired currentDesired ) { cout << " something " << endl; t = PL_new_term_ref( ); } Without t=PL_new_term_ref() everything works fine, but when I start adding my Prolog code (declarations first, such as t=PL_new_term_ref), I get this Access Violation error message. I'd appreciate any help. Thanks,

    Read the article

  • How to create a generic C free function .

    - by nomemory
    I have some C structures related to a 'list' data structure. They look like this. struct nmlist_element_s { void *data; struct nmlist_element_s *next; }; typedef struct nmlist_element_s nmlist_element; struct nmlist_s { void (*destructor)(void *data); int (*cmp)(const void *e1, const void *e2); unsigned int size; nmlist_element *head; nmlist_element *tail; }; typedef struct nmlist_s nmlist; This way I can have different data types being hold in "nmlist_element-data" . The "constructor" (in terms of OOP) has the following signature: nmlist *nmlist_alloc(void (*destructor)(void *data)); Where "destructor" is specific function that de-allocated "data" (being hold by the nmlist_element). If I want to have a list containing integers as data, my "destructor" would like this: void int_destructor(void *data) { free((int*)data); } Still i find it rather "unfriendly" for me to write a destructor functions for every simple primitive data type. So is there a trick to write something like this ? (for primitives): void "x"_destructor(void *data, "x") { free(("x" *)data); } PS: I am not a macro fan myself, and in my short experience regarding C, i don't use them, unless necessary.

    Read the article

  • optimize 2D array in C++

    - by Hristo
    I'm dealing with a 2D array with the following characteristics: const int cols = 500; const int rows = 100; int arr[rows][cols]; I access array arr in the following manner to do some work: for(int k = 0; k < T; ++k) { // for each trainee myscore[k] = 0; for(int i = 0; i < N; ++i) { // for each sample for(int j = 0; j < E[i]; ++j) { // for each expert myscore[k] += delta(i, anotherArray[k][i], arr[j][i]); } } } So I am worried about the array 'arr' and not the other one. I need to make this more cache-friendly and also boost the speed. I was thinking perhaps transposing the array but I wasn't sure how to do that. My implementation turns out to only work for square matrices. How would I make it work for non-square matrices? Also, would mapping the 2D array into a 1D array boost the performance? If so, how would I do that? Finally, any other advice on how else I can optimize this... I've run out of ideas, but I know that arr[j][i] is the place where I need to make changes because I'm accessing columns by columns instead of rows by rows so that is not cache friendly at all. Thanks, Hristo

    Read the article

  • 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?

    Read the article

  • Make phone browser open a URL on Symbian S60 3rd Ed programmatically

    - by ardsrk
    On clicking a URL displayed in my application running on a Symbian S60 3rd Edition device should make the phone browser ( which is already open ) open the specified URL. Here is the code: _LIT( KUrlPrefix,"4 " ) void CMunduIMAppUi::OpenInBrowser(const TDesC& aUrl) { HBufC *url = NULL; const TInt KWmlBrowserUid =0x10008D39; TUid id( TUid::Uid( KWmlBrowserUid ) ); TApaTaskList taskList( CEikonEnv::Static()->WsSession() ); TApaTask task = taskList.FindApp( id ); // Checks if the browser is already open if ( task.Exists() ) { HBufC8* parameter = HBufC8::NewL( aUrl.Length()+ KUrlPrefix().Length()); parameter->Des().Copy(KUrlPrefix); parameter->Des().Append(aUrl); task.BringToForeground(); task.SendMessage(TUid::Uid(0), *parameter); // UID not used delete parameter; parameter = NULL; } } When I use this code to open a URL the browser comes to the foreground but does not get directed to the URL. I suspect something is wrong in SendMessage call that is called after the browser is brought to foreground: task.SendMessage(TUid::Uid(0), *parameter); // UID not used

    Read the article

< Previous Page | 61 62 63 64 65 66 67 68 69 70 71 72  | Next Page >