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  • ASIHTTPRequest wrapper usage for Macs

    - by Rob
    I am trying to apply the ASIHTTPRequest wrapper to a very basic Objective C program. I have already copied over the necessary files into my program and after giving myself an extreme headache trying to figure out how it works through their website I thought I would post a question on here. The files copied over were: ASIHTTPRequestConfig.h ASIHTTPRequestDelegate.h ASIProgressDelegate.h ASIInputStream.h ASIInputStream.m ASIHTTPRequest.h ASIHTTPRequest.m ASIFormDataRequest.h ASIFormDataRequest.m My program is very basic: #import <Foundation/Foundation.h> int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; // Defining the various variables. char firstName[20]; char lastName[20]; char rank[5]; int leaveAccrued; int leaveRequested; // User Input. NSLog (@"Please input First Name:"); scanf("%s", &firstName); NSLog (@"Please input Last Name:"); scanf("%s", &lastName); NSLog (@"Please input Rank:"); scanf("%s", &rank); NSLog (@"Please input the number leave days you have accrued:"); scanf("%i", &leaveAccrued); NSLog (@"Please input the number of leave days you are requesting:"); scanf("%i", &leaveRequested); // Print results. NSLog (@"Name: %s %s", firstName, lastName); NSLog (@"Rank: %s", rank); NSLog (@"Leave Accrued: %i", leaveAccrued); NSLog (@"Leave Requested: %i", leaveRequested); [pool drain]; return 0; } How do I utilize the wrapper to export these 5 basic variables to a web server via an http request?

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  • Compiled Haskell libraries with FFI imports are invalid when imported into GHCI

    - by John Millikin
    I am using GHC 6.12.1, in Ubuntu 10.04 When I try to use the FFI syntax for static storage, only modules running in interpreted mode (ie GHCI) work properly. Compiled modules have invalid pointers, and do not work. I'd like to know whether anybody can reproduce the problem, whether this an error in my code or GHC, and (if the latter) whether it's a known issue. I'm using sys_siglist because it's present in a standard library on my system, but I don't believe the actual storage used matters (I discovered this while writing a binding to libidn). If it helps, sys_siglist is defined in <signal.h> as: extern __const char *__const sys_siglist[_NSIG]; I thought this type might be the problem, so I also tried wrapping it in a plain C procedure: #include<stdio.h> const char **test_ffi_import() { printf("C think sys_siglist = %X\n", sys_siglist); return sys_siglist; } However, importing that doesn't change the result, and the printf() call prints the same pointer value as show siglist_a. My suspicion is that it's something to do with static and dynamic library loading. Update: somebody in #haskell suggested this might be 64-bit specific; if anybody tries to reproduce it, can you mention your architecture and whether it worked in a comment? Code as follows: -- A.hs {-# LANGUAGE ForeignFunctionInterface #-} module A where import Foreign import Foreign.C foreign import ccall "&sys_siglist" siglist_a :: Ptr CString -- -- B.hs {-# LANGUAGE ForeignFunctionInterface #-} module B where import Foreign import Foreign.C foreign import ccall "&sys_siglist" siglist_b :: Ptr CString -- -- Main.hs {-# LANGUAGE ForeignFunctionInterface #-} module Main where import Foreign import Foreign.C import A import B foreign import ccall "&sys_siglist" siglist_main :: Ptr CString main = do putStrLn $ "siglist_a = " ++ show siglist_a putStrLn $ "siglist_b = " ++ show siglist_b putStrLn $ "siglist_main = " ++ show siglist_main peekSiglist "a " siglist_a peekSiglist "b " siglist_b peekSiglist "main" siglist_main peekSiglist name siglist = do ptr <- peekElemOff siglist 2 str <- maybePeek peekCString ptr putStrLn $ "siglist_" ++ name ++ "[2] = " ++ show str I would expect something like this output, where all pointer values identical and valid: $ runhaskell Main.hs siglist_a = 0x00007f53a948fe00 siglist_b = 0x00007f53a948fe00 siglist_main = 0x00007f53a948fe00 siglist_a [2] = Just "Interrupt" siglist_b [2] = Just "Interrupt" siglist_main[2] = Just "Interrupt" However, if I compile A.hs (with ghc -c A.hs), then the output changes to: $ runhaskell Main.hs siglist_a = 0x0000000040378918 siglist_b = 0x00007fe7c029ce00 siglist_main = 0x00007fe7c029ce00 siglist_a [2] = Nothing siglist_b [2] = Just "Interrupt" siglist_main[2] = Just "Interrupt"

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  • Help regarding Android NDK

    - by Siva Kumar
    I am a beginner in using Android NDK. I am using Eclipse and I installed cygwin to build the c file to generate the .so file But while building the c file in cygwin I am always getting the error make: ***No rule to make target 'file.c' ... .Stop I tried building different C codes but for every file it says the same error .. Here is the source code: public class ndktest extends Activity { static { System.loadLibrary("ndkt"); } private native void helloLog(String logThis); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); helloLog("this is to test log file"); } } file.c void Java_com_ndktest_helloLog(JNIEnv * env, jobject this, jstring logThis) { jboolean isCopy; const char * szLogThis = (*env)->GetStringUTFChars(env, logThis, &isCopy); (*env)->ReleaseStringUTFChars(env, logThis, szLogThis); } And here is my Android.mk LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_LDLIBS := -llog LOCAL_MODULE := ndkt LOCAL_SRC_FILES := file.c include $(BUILD_SHARED_LIBRARY) I searched for the solution for the cause of error ... but nothing works for me. Can anyone tell me where I am making the mistake ? Thanks, Siva Kumar

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  • embedded SWF isn't shown (SWFLoader)

    - by Trantec
    I embed a swf as ByteArray and load it at runtime with the SWFLoader. Here is the internal swf that I want to load: <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Label id="rLabel" text="From InternalSWF"/> </mx:Application> The embeding swf loads it with the following code: <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" applicationComplete="main();"> <mx:Script> <![CDATA[ import mx.managers.SystemManager; import mx.events.FlexEvent; [Embed(source="../../InternalSWF/bin-release/InternalSWF.swf", mimeType="application/octet-stream")] mimeType="application/octet-stream")] private const internalSWF:Class; public function main(): void { var binary:ByteArray = new internalSWF() as ByteArray; // setup swfloader rSwfLoader.trustContent = true; rSwfLoader.addEventListener( Event.COMPLETE, onSWFLoaded ); rSwfLoader.load(binary); } public function onSWFLoaded( event:Event ): void { } ]]> </mx:Script> <mx:Box> <mx:SWFLoader id="rSwfLoader" height="100%" width="100%" scaleContent="true"/> <mx:Text id="rText" text="from EmbedingSWF"/> </mx:Box> The label "from EmbedingSWF" is shown on both, local and on the webserver. But the label with "From InternalSWF" isn't shown on the webserver, just on the local machine. With some tests I found out that the internal swf is loaded correctly, because it's later added applicationComplete-Function is called. Is this a bug in Adobe-Flash-Player or am I missunderstanding something ? Update: Internet Explorer is fine. Firefox and Chrome not...

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  • Why do I get CA1806 when I catch exception in C++/CLI?

    - by brickner
    I've recently upgraded my project from Visual Studio 2008 to Visual Studio 2010. By enabling Code Analysis and compiling in Release, I'm getting warning CA1806: Do not ignore method results. I've managed to reduce the code that produces the warning to this code: .h file: public ref class Foo { public: void Bar(); }; .cpp file: void Foo::Bar() { try { } catch (const std::exception&) // here I get the warning { } } the warning: CA1806 : Microsoft.Usage : 'Foo::Bar(void)' calls 'Global::__CxxRegisterExceptionObject(void*, void*)' but does not use the HRESULT or error code that the method returns. This could lead to unexpected behavior in error conditions or low-resource situations. Use the result in a conditional statement, assign the result to a variable, or pass it as an argument to another method. If I try to use the exception value or do catch(...) the warning still appears. If I catch managed exceptions instead or compile in Debug I don't get the warning. Why do I get this warning? UPDATE I've decided to open a bug report on Microsoft Connect.

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  • Copy vector of values to vector of pairs in one line

    - by Kirill V. Lyadvinsky
    I have the following types: struct X { int x; X( int val ) : x(val) {} }; struct X2 { int x2; X2() : x2() {} }; typedef std::pair<X, X2> pair_t; typedef std::vector<pair_t> pairs_vec_t; typedef std::vector<X> X_vec_t; I need to initialize instance of pairs_vec_t with values from X_vec_t. I use the following code and it works as expected: int main() { pairs_vec_t ps; X_vec_t xs; // this is not empty in the production code ps.reserve( xs.size() ); { // I want to change this block to one line code. struct get_pair { pair_t operator()( const X& value ) { return std::make_pair( value, X2() ); } }; std::transform( xs.begin(), xs.end(), back_inserter(ps), get_pair() ); } return 0; } What I'm trying to do is to reduce my copying block to one line with using boost::bind. This code is not working: for_each( xs.begin(), xs.end(), boost::bind( &pairs_vec_t::push_back, ps, boost::bind( &std::make_pair, _1, X2() ) ) ); I know why it is not working, but I want to know how to make it working without declaring extra functions and structs?

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  • Template operator linker error

    - by Dani
    I have a linker error I've reduced to a simple example. The build output is: debug/main.o: In function main': C:\Users\Dani\Documents\Projects\Test1/main.cpp:5: undefined reference tolog& log::operator<< (char const (&) [6])' collect2: ld returned 1 exit status It looks like the linker ignores the definition in log.cpp. I also cant put the definition in log.h because I include the file alot of times and it complains about redefinitions. main.cpp: #include "log.h" int main() { log() << "hello"; return 0; } log.h: #ifndef LOG_H #define LOG_H class log { public: log(); template<typename T> log &operator <<(T &t); }; #endif // LOG_H log.cpp: #include "log.h" #include <iostream> log::log() { } template<typename T> log &log::operator <<(T &t) { std::cout << t << std::endl; return *this; }

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  • How to provide js-ctypes in a spidermonkey embedding?

    - by Triston J. Taylor
    Summary I have looked over the code the SpiderMonkey 'shell' application uses to create the ctypes JavaScript object, but I'm a less-than novice C programmer. Due to the varying levels of insanity emitted by modern build systems, I can't seem to track down the code or command that actually links a program with the desired functionality. method.madness This js-ctypes implementation by The Mozilla Devs is an awesome addition. Since its conception, scripting has been primarily used to exert control over more rigorous and robust applications. The advent of js-ctypes to the SpiderMonkey project, enables JavaScript to stand up and be counted as a full fledged object oriented rapid application development language flying high above 'the bar' set by various venerable application development languages such as Microsoft's VB6. Shall we begin? I built SpiderMonkey with this config: ./configure --enable-ctypes --with-system-nspr followed by successful execution of: make && make install The js shell works fine and a global ctypes javascript object was verified operational in that shell. Working with code taken from the first source listing at How to embed the JavaScript Engine -MDN, I made an attempt to instantiate the JavaScript ctypes object by inserting the following code at line 66: /* Populate the global object with the ctypes object. */ if (!JS_InitCTypesClass(cx, global)) return NULL; /* I compiled with: g++ $(./js-config --cflags --libs) hello.cpp -o hello It compiles with a few warnings: hello.cpp: In function ‘int main(int, const char**)’: hello.cpp:69:16: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] hello.cpp:80:20: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] hello.cpp:89:17: warning: NULL used in arithmetic [-Wpointer-arith] But when you run the application: ./hello: symbol lookup error: ./hello: undefined symbol: JS_InitCTypesClass Moreover JS_InitCTypesClass is declared extern in 'dist/include/jsapi.h', but the function resides in 'ctypes/CTypes.cpp' which includes its own header 'CTypes.h' and is compiled at some point by some command during 'make' to yeild './CTypes.o'. As I stated earlier, I am less than a novice with the C code, and I really have no idea what to do here. Please give or give direction to a generic example of making the js-ctypes object functional in an embedding.

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  • How to modulate every texture unit in OpenGL ES 1.1?

    - by Jesse Beder
    I have two textures and a "blend factor", and I'd like to mix them, modulated by the current color; in effect, I want to use the following shader: gl_FragColor = gl_Color * mix(tex0, tex1, blendFactor); I'm using OpenGL ES 1.1, targeting all versions of the iPhone, so I can't use shaders, and I have two texture units. My best attempt is: // texture 0 glActiveTexture(GL_TEXTURE0); image1.Bind(); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); // texture 1 glActiveTexture(GL_TEXTURE1); image2.Bind(); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE); glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_INTERPOLATE); glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_RGB, GL_PREVIOUS); glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR); glTexEnvi(GL_TEXTURE_ENV, GL_SRC1_RGB, GL_TEXTURE); glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_COLOR); glTexEnvi(GL_TEXTURE_ENV, GL_SRC2_RGB, GL_CONSTANT); glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB, GL_SRC_ALPHA); glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_INTERPOLATE); glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_PREVIOUS); glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA); glTexEnvi(GL_TEXTURE_ENV, GL_SRC1_ALPHA, GL_TEXTURE); glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, GL_SRC_ALPHA); glTexEnvi(GL_TEXTURE_ENV, GL_SRC2_ALPHA, GL_CONSTANT); glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_ALPHA, GL_SRC_ALPHA); const float factor[] = { 0, 0, 0, blendFactor }; glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, factor); This has the effect of the shader: gl_FragColor = mix(gl_Color * tex0, tex1, blendFactor); but I don't see how to module texture 1 by the color. Is there any way to have the color provided by a texture unit automatically modulated by the incoming primary color? Or any other way to do what I want that I'm missing? Multiple passes are definitely allowed, but they have to have the proper blend effect; I have glBlend(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); enabled, so it can be tricky to get right with multiple passes.

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  • How to covert UTF8 string to UTF16 in JNI

    - by Er Rahul Rajkumar Gupta
    Can anyone please tell me that what is going on wrong with me in this code.Actually in following line of codes I am taking the path of sdcard in a string in jni (C code) and in concatenate function concatenating these manually using loop.The string returned by concatenate works fine but when I am converting it to jstring it prints garbage value in my logcat. Kindly tell me what is the problem. jstring str=(jstring)env->CallObjectMethod(sdcard,storagestring); const char jclass cfile=env->FindClass("java/io/File"); jmethodID fileid=env->GetMethodID(cfile,"<init>","(Ljava/lang/String;)V"); jclass envir=env->FindClass("android/os/Environment"); jmethodID storageid=env->GetStaticMethodID(envir,"getExternalStorageDirectory","()Ljava/io/File;"); jobject sdcard=env->CallStaticObjectMethod(envir,storageid); jclass sdc=env->GetObjectClass(sdcard); jmethodID storagestring=env->GetMethodID(sdc,"toString","()Ljava/lang/String;"); *nativeString = env->GetStringUTFChars(str, 0); char *s =concatenate(nativeString,"/f1.3gp"); //fpath=s; fpath=env->NewStringUTF(s); jobject fobject=env->NewObject(cfile,fileid,fpath); LOGI("size of char=%d size of string=%d",sizeof("/f1.3gp"),sizeof(fpath)); jmethodID existid=env->GetMethodID(cfile,"exists","()Z"); if(env->CallBooleanMethod(fobject,existid)) { jmethodID delid=env->GetMethodID(cfile,"delete","()Z"); if(env->CallBooleanMethod(fobject,delid)) LOGE("File is deleting...%s",env->NewStringUTF("/f1.3gp")); } jmethodID newfileid=env->GetMethodID(cfile,"createNewFile","()Z"); if(env->CallBooleanMethod(fobject,newfileid)) LOGE("dig dig %s",fpath); jthrowable exc=env->ExceptionOccurred(); if(exc) { env->ExceptionDescribe(); env->ExceptionClear(); } LOGE("creating file %s",fpath); }

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  • {DCC Warning} W1036 Variable '$frame' might not have been initialized?

    - by Gad D Lord
    Any ideas why I get this warning in Delphi XE: [DCC Warning] Form1.pas(250): W1036 Variable '$frame' might not have been initialized procedure TForm1.Action1Execute(Sender: TObject); var Thread: TThread; begin ... Thread := TThread.CreateAnonymousThread( procedure{Anonymos}() procedure ShowLoading(const Show: Boolean); begin /// <------------- WARNING IS GIVEN FOR THIS LINE (line number 250) Thread.Synchronize(Thread, procedure{Anonymous}() begin ... Button1.Enabled := not Show; ... end ); end; var i: Integer; begin ShowLoading(true); try Thread.Synchronize(Thread, procedure{Anonymous}() begin ... // some UI updates end Thread.Synchronize(Thread, procedure{Anonymous}() begin ... // some UI updates end ); finally ShowLoading(false); end; end ).NameThread('Some Thread Name'); Thread.Start; end; I do not have anywhere in my code a variable names frame nor $frame. I am even not sure how $frame with $ sign can be a valid identifier. Smells like compiler magic to me. PS: Of course the real life xosw is having other than Form1, Button1, Action1 names.

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  • server/ client server connection

    - by user312054
    I have a server side program that creates a listening server side socket. The problem occurring is that it seems as if the client side sends a connect request it gets rejected if the server side socket is listening but connects if the server side program is not running. I can see the server side program getting the client request when debugging. It seems as if the client cannot connect to a listening socket. Any suggestions on a resolution? The server side accept code snippet is this. void CSocketListen::OnAccept(int nErrorCode) { CSocket::OnAccept(nErrorCode); CSocketServer* SocketPtr = new CSocketServer(); if (Accept(*SocketPtr)) { // add to list of client sockets connected } else { delete SocketPtr; } The client side code connect is like this. SOCKET cellModem; sockaddr_in handHeld; handHeld.sin_family = AF_INET; //Address family handHeld.sin_addr.s_addr = inet_addr("127.0.0.1"); handHeld.sin_port = htons((u_short)1113); //port to use cellModem=socket(AF_INET,SOCK_STREAM,0); if(cellModem == INVALID_SOCKET) { // log socket failure return false; } else { // log socket success } if (connect(cellModem,(const struct sockaddr*)&handHeld, sizeof(handHeld)) != 0 ) { // log socket connection success } else { // log socket connection failure closesocket(cellModem); }

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  • SDL with OpenGL (freeglut) crashes on call to glutBitmapCharacter

    - by stett
    I have a program using OpenGL through freeglut under SDL. The SDL/OpenGL initialization is as follows: // Initialize SDL SDL_Init(SDL_INIT_VIDEO); // Create the SDL window SDL_SetVideoMode(SCREEN_W, SCREEN_H, SCREEN_DEPTH, SDL_OPENGL); // Initialize OpenGL glClearColor(BG_COLOR_R, BG_COLOR_G, BG_COLOR_B, 1.f); glViewport(0, 0, SCREEN_W, SCREEN_H); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0.0f, SCREEN_W, SCREEN_H, 0.0f, -1.0f, 1.0f); glEnable(GL_TEXTURE_2D); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); I've been using glBegin() ... glEnd() blocks without any trouble to draw primitives. However, in this program when I call any glutBitmapX function, the program simply exits without an error status. The code I'm using to draw text is: glColor3f(1.f, 1.f, 1.f); glRasterPos2f(x, y); glutStrokeString(GLUT_BITMAP_8_BY_13, (const unsigned char*)"test string"); In previous similar programs I've used glutBitmapCharacter and glutStrokeString to draw text and it's seemed to work. The only difference being that I'm using freeglut with SDL now instead of just GLUT as I did in previous programs. Is there some fundamental problem with my setup that I'm not seeing, or is there a better way of drawing text?

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  • vector::erase with pointer member

    - by matt
    I am manipulating vectors of objects defined as follow: class Hyp{ public: int x; int y; double wFactor; double hFactor; char shapeNum; double* visibleShape; int xmin, xmax, ymin, ymax; Hyp(int xx, int yy, double ww, double hh, char s): x(xx), y(yy), wFactor(ww), hFactor(hh), shapeNum(s) {visibleShape=0;shapeNum=-1;}; //Copy constructor necessary for support of vector::push_back() with visibleShape Hyp(const Hyp &other) { x = other.x; y = other.y; wFactor = other.wFactor; hFactor = other.hFactor; shapeNum = other.shapeNum; xmin = other.xmin; xmax = other.xmax; ymin = other.ymin; ymax = other.ymax; int visShapeSize = (xmax-xmin+1)*(ymax-ymin+1); visibleShape = new double[visShapeSize]; for (int ind=0; ind<visShapeSize; ind++) { visibleShape[ind] = other.visibleShape[ind]; } }; ~Hyp(){delete[] visibleShape;}; }; When I create a Hyp object, allocate/write memory to visibleShape and add the object to a vector with vector::push_back, everything works as expected: the data pointed by visibleShape is copied using the copy-constructor. But when I use vector::erase to remove a Hyp from the vector, the other elements are moved correctly EXCEPT the pointer members visibleShape that are now pointing to wrong addresses! How to avoid this problem? Am I missing something?

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  • Weird Qt SSL issue -- error "No Error" shows up, nothing else, and if I ignore it, everything works

    - by houbysoft
    The issue is as follows : in my Qt app, I have a QWebView, which I use to load a HTTPS page. Everything worked fine on my development machine, so I'm now trying to get it to run on a test machine. I ran the app, but the page didn't load (the QWebView was blank). After much debugging, I found the problem is that an SSL error shows up, and the sslErrors() signal is fired. Here is my sslErrors() handling code: void blah::sslErrors(QNetworkReply *reply, const QList<QSslError> &errors) { foreach(QSslError error, errors) { qDebug() << error.errorString() << endl; } reply->ignoreSslErrors(); } The only thing the above code prints is: "No error" So there's no error, but unless I call reply->ignoreSslErrors(), the page doesn't load (on the test machine, on my developer computer no error is reported). Huh? Is this a bug? Is it safe to ignore the error, if I make sure it's of the type "No error"?

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  • Function parameters evaluation order: is undefined behaviour if we pass reference?

    - by bolov
    This is undefined behaviour: void feedMeValue(int x, int a) { cout << x << " " << a << endl; } int main() { int a = 2; int &ra = a; feedMeValue(ra = 3, a); return 0; } because depending on what parameter gets evaluated first we could call (3, 2) or (3, 3). However this: void feedMeReference(int x, int const &ref) { cout << x << " " << ref << endl; } int main() { int a = 2; int &ra = a; feedMeReference(ra = 3, a); return 0; } will always output 3 3 since the second parameter is a reference and all parameters have been evaluated before the function call, so even if the second parameter is evaluated before of after ra = 3, the function received a reference to a wich will have a value of 2 or 3 at the time of the evaluation, but will always have the value 3 at the time of the function call. Is the second example UB? It is important to know because the compiler is free to do anything if he detects undefined behaviour, even if I know it would always yield the same results. *Note: I think that feedMeReference(a = 3, a) is the exact same situation as feedMeReference(ra = 3, a). However it seems not everybody agrees, in the addition to having 2 completely different answers.

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  • How to produce output using show function.

    - by wilson88
    I am trying to use sho to show the output of another function.The first function was used to do sorting, and returned a List. now I want to make a function that uses show() to display the output.This is how I had tried it only to get an error. Its to diplay the results of two the two sorted lists which used this function. map Auctioneer::compareBidList(map& one, map& two) and //**return Sorted.** void show(const char *msg, map<int, Bid*>& Sorted) { cout << msg << endl; show(Sorted); } void compare(map<int, Bid*>& sellers, map<int, Bid*>& buyers) { compare(sellers.begin(), sellers.end(), buyers.begin(),buyers.end(),compareBidList); } //my call in the main after declaration was as follows map<int, Bid*> buyers, sellers; Auctioneer auctioneer; auctioneer.compare(sellers,buyers); show(("Bids after sorting:", sellers,buyers);)

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  • Applying policy based design question

    - by Arthur
    I've not read the Modern C++ Design book but have found the idea of behavior injection through templates interesting. I am now trying to apply it myself. I have a class that has a logger that I thought could be injected as a policy. The logger has a log() method which takes an std::string or std::wstring depending on its policy: // basic_logger.hpp template<class String> class basic_logger { public: typedef String string_type; void log(const string_type & s) { ... } }; typedef basic_logger<std::string> logger; typedef basic_logger<std::wstring> wlogger; // reader.hpp template<class Logger = logger> class reader { public: typedef Logger logger_type; void read() { _logger.log("Reading..."); } private: logger_type _logger; }; Now the questing is, should the reader take a Logger as an argument, like above, or should it take a String and then instantiate a basic_logger as an instance variable? Like so: template<class String> class reader { public: typedef String string_type; typedef basic_logger<string_type> logger_type; // ... private: logger_type _logger; }; What is the right way to go?

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  • accumulator don't compile

    - by Abruzzo Forte e Gentile
    HI All I am using boost accumulators. These 2 lines use to work fine with current version of boost in LInux. accumulator_set< double, stats< tag::covariance<double, tag::covariate1> > > acc_cov; accumulator_set< double, stats< tag::variance > > acc_var; When I moved to a Sun machine where it is installed boost v1.40 I have this building error "/opt/boost/boost/accumulators/framework/depends_on.hpp", line 276: Error:<no tag> cannot be initialized in a constructor. "/opt/boost/boost/fusion/container/list/cons.hpp", line 85: Where: While instantiating "boost::accumulators::detail::accumulator_wrapper<int, int>::accumulator_wrapper(const boost::accumulators::detail::accumulator_wrapper<int, int>&)". "/opt/boost/boost/fusion/container/list/cons.hpp", line 85: Where: Instantiated from non-template code. 1 Error(s) Do you know how can I fix those errors and why I have this issue? Thanks AFG

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  • Need advice on comparing the performance of 2 equivalent linq to sql queries

    - by uvita
    I am working on tool to optimize linq to sql queries. Basically it intercepts the linq execution pipeline and makes some optimizations like for example removing a redundant join from a query. Of course, there is an overhead in the execution time before the query gets executed in the dbms, but then, the query should be processed faster. I don't want to use a sql profiler because I know that the generated query will be perform better in the dbms than the original one, I am looking for a correct way of measuring the global time between the creation of the query in linq and the end of its execution. Currently, I am using the Stopwatch class and my code looks something like this: var sw = new Stopwatch(); sw.Start(); const int amount = 100; for (var i = 0; i < amount; i++) { ExecuteNonOptimizedQuery(); } sw.Stop(); Console.Writeline("Executing the query {2} times took: {0}ms. On average, each query took: {1}ms", sw.ElapsedMilliseconds, sw.ElapsedMilliseconds / amount, amount); Basically the ExecutenNonOptimizedQuery() method creates a new DataContext, creates a query and then iterates over the results. I did this for both versions of the query, the normal one and the optimized one. I took the idea from this post from Frans Bouma. Is there any other approach/considerations I should take? Thanks in advance!

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  • Overloading operator>> to a char buffer in C++ - can I tell the stream length?

    - by exscape
    I'm on a custom C++ crash course. I've known the basics for many years, but I'm currently trying to refresh my memory and learn more. To that end, as my second task (after writing a stack class based on linked lists), I'm writing my own string class. It's gone pretty smoothly until now; I want to overload operator that I can do stuff like cin my_string;. The problem is that I don't know how to read the istream properly (or perhaps the problem is that I don't know streams...). I tried a while (!stream.eof()) loop that .read()s 128 bytes at a time, but as one might expect, it stops only on EOF. I want it to read to a newline, like you get with cin to a std::string. My string class has an alloc(size_t new_size) function that (re)allocates memory, and an append(const char *) function that does that part, but I obviously need to know the amount of memory to allocate before I can write to the buffer. Any advice on how to implement this? I tried getting the istream length with seekg() and tellg(), to no avail (it returns -1), and as I said looping until EOF (doesn't stop reading at a newline) reading one chunk at a time.

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  • How to iterate over modifed std::map values?

    - by Frank
    I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

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  • PDCurses TUI with C++ Win32 console application

    - by Bach
    I have downloaded pdcurses source and was able to successfully include curses.h in my project, linked the pre-compiled library and all good. After few hours of trying out the library, I saw the tuidemo.c in the demos folder, compiled it into an executable and brilliant! exactly what I needed for my project. Now the problem is that it's a C code, and I am working on a C++ project in VS c++ 2008. The files I need are tui.c and tui.h How can I include that C file in my C++ code? I saw few suggestions here but the compiler was not too happy with 100's of warnings and errors. How can I go on including/using that TUI pdcurses includes!? Thanks EDIT: I added extern "C" statement, so my test looks like this now, but I'm getting some other type of error #include <stdio.h> #include <stdlib.h> using namespace std; extern "C" { #include <tui.h> } void sub0(void) { //do nothing } void sub1(void) { //do nothing } int main (int argc, char * const argv[]) { menu MainMenu[] = { { "Asub", sub0, "Go inside first submenu" }, { "Bsub", sub1, "Go inside second submenu" }, { "", (FUNC)0, "" } /* always add this as the last item! */ }; startmenu(MainMenu, "TUI - 'textual user interface' demonstration program"); return 0; } Although it is compiling successfully, it is throwing an Error at runtime: 0xC0000005: Access violation reading location 0x021c52f9 at line startmenu(MainMenu, "TUI - 'textual user interface' demonstration program"); Not sure where to go from here. thanks again.

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  • lambda traits inconsistency across C++0x compilers

    - by Sumant
    I observed some inconsistency between two compilers (g++ 4.5, VS2010 RC) in the way they match lambdas with partial specializations of class templates. I was trying to implement something like boost::function_types for lambdas to extract type traits. Check this for more details. In g++ 4.5, the type of the operator() of a lambda appears to be like that of a free standing function (R (*)(...)) whereas in VS2010 RC, it appears to be like that of a member function (R (C::*)(...)). So the question is are compiler writers free to interpret any way they want? If not, which compiler is correct? See the details below. template <typename T> struct function_traits : function_traits<decltype(&T::operator())> { // This generic template is instantiated on both the compilers as expected. }; template <typename R, typename C> struct function_traits<R (C::*)() const> { // inherits from this one on VS2010 RC typedef R result_type; }; template <typename R> struct function_traits<R (*)()> { // // inherits from this one g++ 4.5 typedef R result_type; }; int main(void) { auto lambda = []{}; function_traits<decltype(lambda)>::result_type *r; // void * } This program compiles on both g++ 4.5 and VS2010 but the function_traits that are instantiated are different as noted in the code.

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  • Need help in reading callgrind output

    - by n179911
    Hi, I have run callgrind with my application like this "valgrind --tool=callgrind MyApplication" and then call 'callgrind_annotate --auto=yes ./callgrind.out.2489' I see output like 768,097,560 PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 18,624,794 /build/buildd/eglibc-2.11.1/elf/dl-lookup.c:do_lookup_x [/lib/ld-2.11.1.so] 18,149,492 /src/js/src/jsgc.cpp:JS_CallTracer'2 [/src/firefox-debug-objdir/js/src/libmozjs.so] 16,328,897 /src/layout/style/nsCSSDataBlock.cpp:nsCSSExpandedDataBlock::DoAssertInitialState() [/src/firefox-debug-objdir/toolkit/library/libxul.so] 13,376,634 /build/buildd/eglibc-2.11.1/nptl/pthread_getspecific.c:pthread_getspecific [/lib/libpthread-2.11.1.so] 13,005,623 /build/buildd/eglibc-2.11.1/malloc/malloc.c:_int_malloc [/lib/libc-2.11.1.so] 10,404,453 ???:0x0000000000009190 [/usr/lib/libpangocairo-1.0.so.0.2800.0] 10,358,646 /src/xpcom/io/nsFastLoadFile.cpp:NS_AccumulateFastLoadChecksum(unsigned int*, unsigned char const*, unsigned int, int) [/src/firefox-debug-objdir/toolkit/library/libxul.so] 8,543,634 /src/js/src/jsscan.cpp:js_GetToken [/src/firefox-debug-objdir/js/src/libmozjs.so] 7,451,273 /src/xpcom/typelib/xpt/src/xpt_arena.c:XPT_ArenaMalloc [/src/firefox-debug-objdir/toolkit/library/libxul.so] 7,335,131 ???:g_type_check_instance_is_a [/usr/lib/libgobject-2.0.so.0.2400.0] I have a few questions: What does the number on the right mean? Does it mean it spend accumulative that long in calling the function on the right? How can I tell how many times that function has been called and Does that include the time spend in calling the functions called by that function? What does line with ??? mean? e.g. ???:0x0000000000009190 [/usr/lib/libpangocairo-1.0.so.0.2800.0] Thank you.

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