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  • File in binary form

    - by Abhi
    Dear All I want to write data into the file in binary form. I was trying using the mentioned below FILE *fp = fopen("binaryoutput.rgb888", "ab+"); for(int m=0; m<height; m++) { for (int n=0; n< width; n++) { temp = (pOutputImg+m*3+n*3); // here temp is a pointer to a unsigned char fprintf(fp,"%u",*temp); } } fclose(fp); I am able to get data which is strored at pOutputImg but not in binary form. Can anyone guide me the correct step.. Thanks in advance

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  • If free() knows the length of my array, why can't I ask for it in my own code?

    - by Chris Cooper
    I know that it's a common convention to pass the length of dynamically allocated arrays to functions that manipulate them: void initializeAndFree(int* anArray, int length); int main(){ int arrayLength = 0; scanf("%d", &arrayLength); int* myArray = (int*)malloc(sizeof(int)*arrayLength); initializeAndFree(myArray, arrayLength); } void initializeAndFree(int* anArray, int length){ int i = 0; for (i = 0; i < length; i++) { anArray[i] = 0; } free(anArray); } but if there's no way for me to get the length of the allocated memory from a pointer, how does free() "automagically" know what to deallocate? Why can't I get in on the magic, as a C programmer? Where does free() get its free (har-har) knowledge from?

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  • How to change input button image using CSS?

    - by Baltimark
    So, I can create an input button with an image using <INPUT type="image" src="/images/Btn.PNG" value=""> But, I can't get the same behavior using CSS. for instance, i've tried <INPUT type="image" class="myButton" value=""> where "myButton" is defined in the css file as .myButton{ background:url(/images/Btn.PNG) no-repeat; cursor:pointer; width: 200px; height: 100px; border: none; } If that's all I wanted to do, I could use the original style, but I want to change the button's appearance on hover (using a myButton:hover class). I know the links are good because I've been able to load them for a background image for other parts of the page (just as a check). I found examples on the web of how to do it using javascript, but I'm looking for a css solution. I'm using Firefox 3.0.3 if that makes a difference. Thanks

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  • Performing time consuming operation on STL container within a lock

    - by Ashley
    I have an unordered_map of an unordered_map which stores a pointer of objects. The unordered map is being shared by multiple threads. I need to iterate through each object and perform some time consuming operation (like sending it through network etc) . How could I lock the multiple unordered_map so that it won't blocked for too long? typedef std::unordered_map<string, classA*>MAP1; typedef std::unordered_map<int, MAP1*>MAP2; MAP2 map2; pthread_mutex_lock(&mutexA) //how could I lock the maps? Could I reduce the lock granularity? for(MAP2::iterator it2 = map2.begin; it2 != map2.end; it2++) { for(MAP1::iterator it1 = *(it2->second).begin(); it1 != *(it2->second).end(); it1++) { //perform some time consuming operation on it1->second eg sendToNetwork(*(it1->second)); } } pthread_mutex_unlock(&mutexA)

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  • How to convert from integer to unsigned char in C, given integers larger than 256?

    - by Alf_InPogform
    As part of my CS course I've been given some functions to use. One of these functions takes a pointer to unsigned chars to write some data to a file (I have to use this function, so I can't just make my own purpose built function that works differently BTW). I need to write an array of integers whose values can be up to 4095 using this function (that only takes unsigned chars). However am I right in thinking that an unsigned char can only have a max value of 256 because it is 1 byte long? I therefore need to use 4 unsigned chars for every integer? But casting doesn't seem to work with larger values for the integer. Does anyone have any idea how best to convert an array of integers to unsigned chars?

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  • Objective-C: Initializing char with char at index of string.

    - by Mr. McPepperNuts
    unichar myChar = [myString characterAtIndex:0]; [myNSMutableArray addObject:myChar]; I am trying to insert the first char of a string into an array, to create an array of chars. the first line does not give me an error. The second line however, provides the following error: warning: passing argument 1 of 'addObject:' makes pointer from integer without a cast This also crashes the application with a "bad address" error. I thought this error was due to a problem with memory allocation. Can someone shed some light on this.

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  • Confused about "override" vs. "new" in C#

    - by iTayb
    I'm having the following classes: class Base { public virtual void Print() { Console.WriteLine("Base"); } } class Der1 : Base { public new virtual void Print() { Console.WriteLine("Der1"); } } class Der2 : Der1 { public override void Print() { Console.WriteLine("Der2"); } } This is my main method: Base b = new Der2(); Der1 d1 = new Der2(); Der2 d2 = new Der2(); b.Print(); d1.Print(); d2.Print(); The output is Base, Der2, Der2. As far as I know, Override won't let previous method to run, even if the pointer is pointing to them. So the first line should output Der2 as well. However Base came out. How is it possible? How the override didn't work there?

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  • Are raw C++ pointers first class objects?

    - by Shailesh Kumar
    According to Wikipedia: An object is first-class when it: can be stored in variables and data structures can be passed as a parameter to a subroutine can be returned as the result of a subroutine can be constructed at runtime has intrinsic identity (independent of any given name) Somebody had once told me that raw pointers are not first class objects while smart pointers like std::auto_ptr are. But to me, a raw pointer (to an object or to a function) in C++ does seem to me to satisfy the conditions stated above to qualify as a first class object. Am I missing something?

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  • Printf ubuntu Segmentation fault (core dumped)

    - by Someone
    I have this code: int a; printf("&a = %u\n",(unsigned)&a); printf("a\n"); printf("b\n"); printf("c\n"); printf("d\n"); I tried to print the pointer of a variable. But it fail on the row printf("a\n"); and says Segmentation fault (core dumped) Output: &a = 134525024 Segmentation fault (core dumped) When I remove the row printf("&a = %u\n",(unsigned)&a); from the code, its success. Output: a b c d What worng in my code?

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  • SWIG-Lua question on class returning another class

    - by John Smith
    I am concreting a question I had earlier. I have two classes in C++ and I use SWIG to wrap them. A method in one class can return a pointer to the other class. How can I get Lua to see it as more than just a userdata? More concretely: I have class fruit { int numberofseeds; //some other stuff about fruit constructors etc... public: getseedcount() { return numberofseeds; } } class tree { fruit * apple; public: //constructors and whatnot fruit * getfruit() { return apple; } } I wrap these two class with SWIG so I can access them in Lua So I can get in Lua the object x=pomona.tree(grannysmith). My question now is: How can I arrange for things so that when I type y=x:getfruit() I will get a pomona:fruit type object? Where I can write something line y:getseedcount()? At the moment all I get is userdata which not edible.

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  • Help for CSS Menu Dropdown, FF OK and IE6 Problem

    - by Taruhku
    IE Problem, FF OK. Please help..???? Screen Shoot problem click here This is my CSS dolphincontainer { position:relative; height:56px; color:#E0E0E0; background:#143D55; width:100%; font-family:Tahoma; left: 0px; } dolphinnav {position:absolute;;height:33px;font-size:12px;font-weight:bold;background:#fff url(images/dolphin_bg.gif) repeat-x bottom left;padding:0 0 0 10px;width:975px;} dolphinnav ul {margin:0;padding:0;list-style-type:none;width:auto;float:left;} dolphinnav ul li {display:block;float:left;margin:0 1px;} dolphinnav ul li a {display:block;float:left;color:#001b2c;text-decoration:none;padding:0 0 0 10px;height:33px;} dolphinnav ul li a span {padding:12px 20px 0 0;height:21px;float:left;font-weight:bold;} dolphinnav ul li a:hover {color:#fff;background:transparent url(images/dolphin_bg-OVER.gif) repeat-x bottom left;} dolphinnav ul li a:hover span {display:block;width:auto;cursor:pointer;} dolphinnav ul li a.current,#dolphinnav ul li a.current:hover {color:#fff;background:#00517e url(images/dolphin_left-ON.gif) no-repeat top left;line-height:275%;} dolphinnav ul li a.current span {display:block;padding:0 20px 0 0;width:auto;background:#00517e url(images/dolphin_right-ON.gif) no-repeat top right;height:33px;} .tuckUp { display:block; width:90px; height:30px; overflow:hidden; cursor:pointer; } .pullDown { width:90px; height:56px; } .item a:link, .item a:visited { display:inline; float:left; background:#fff url(images/dolphin_bg.gif) repeat-x top left;padding:0 0 0 10px; text-align:left; color:#444; font-size:11px; font-weight:bold; text-decoration:none; line-height:25px; margin:0 5px 0px 0px; width:80px; } .item a:hover { display:inline; float:left; background:#39c; color:#FFF; text-decoration:none; text-align:left; font-size:11px; font-weight:700; font-weight:bold; line-height:25px; padding:0 0 0 10px; margin:0 5px 0px 0px; width:80px; } HTML: <div id="dolphincontainer"> <div id="dolphinnav"> <ul> <li><a href="index.php"><span>Home</span></a></li> <li><a href="chooseus.php"><span>Why Choose Us</span></a></li> <li><a href="peraturan.php"><span>Rules</span></a></li> <li class="tuckUp" onmousemove="this.className='pullDown'" onmouseout="this.className='tuckUp'"><a href="#"><span>Transaction</span></a> <div class="item"> <a href="drop1.php">Drop Down 1</a><br /> <a href="drop2.php">Drop Down 2</a></a><br /> <a href="drop3.php">Drop Down 3</a><br /> </div> </li> <li><a href="download.php"><span>Download</span></a></li> <li><a href="aboutus.php"><span>About Us</span></a></li> <li><a href="help.php" class="current"><span>Support</span></a></li> <li><a href="promo.php"><span><font color="#FF0000"><blink>PROMO</blink> </font></span></a></li> </ul> </div> </div>

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  • pass by reference but reference to data and not to variable

    - by dorelal
    This is psesudo code. In what programming language this is possible ? def lab(input) input = ['90'] end x = ['80'] lab(x) puts x #=> value of x has changed from ['80'] to ['90] I have written this in ruby but in ruby I get the final x value of 80 because ruby is pass-by-reference. However what is passed is the reference to the data held by x and not pointer to x itself same is true in JavaScript. So I am wondering if there is any programming language where the following is true.

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  • Multithreading with STL container

    - by Steven
    I have an unordered map which stores a pointer of objects. I am not sure whether I am doing the correct thing to maintain the thread safety. typedef std::unordered_map<string, classA*>MAP1; MAP1 map1; pthread_mutex_lock(&mutexA) if(map1.find(id) != map1.end()) { pthread_mutex_unlock(&mutexA); //already exist, not adding items } else { classA* obj1 = new classA; map1[id] = obj1; obj1->obtainMutex(); //Should I create a mutex for each object so that I could obtain mutex when I am going to update fields for obj1? pthread_mutex_unlock(&mutexA); //release mutex for unordered_map so that other threads could access other object obj1->field1 = 1; performOperation(obj1); //takes some time obj1->releaseMutex(); //release mutex after updating obj1 }

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  • c++/cli pass (managed) delegate to unmanaged code

    - by Ron Klein
    How do I pass a function pointer from managed C++ (C++/CLI) to an unmanaged method? I read a few articles, like this one from MSDN, but it describes two different assemblies, while I want only one. Here is my code: 1) Header (MyInterop.ManagedCppLib.h): #pragma once using namespace System; namespace MyInterop { namespace ManagedCppLib { public ref class MyManagedClass { public: void DoSomething(); }; }} 2) CPP Code (MyInterop.ManagedCppLib.cpp) #include "stdafx.h" #include "MyInterop.ManagedCppLib.h" #pragma unmanaged void UnmanagedMethod(int a, int b, void (*sum)(const int)) { int result = a + b; sum(result); } #pragma managed void MyInterop::ManagedCppLib::MyManagedClass::DoSomething() { System::Console::WriteLine("hello from managed C++"); UnmanagedMethod(3, 7, /* ANY IDEA??? */); } I tried creating my managed delegate and then I tried to use Marshal::GetFunctionPointerForDelegate method, but I couldn't compile.

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  • @OneToyMany property null in Entity after (second) merge

    - by iNPUTmice
    Hi, I'm using JPA (with Hibernate) and Gilead in a GWT project. On the server side I have this method and I'm calling this method twice with the same "campaign". On the second call it throws a null pointer exception in line 4 "campaign.getTextAds()" public List<WrapperTextAd> getTextAds(WrapperCampaign campaign) { campaign = em.merge(campaign); System.out.println("getting textads for "+campaign.getName()); for(WrapperTextAd textad: campaign.getTextAds()) { //do nothing } return new ArrayList<WrapperTextAd>(campaign.getTextAds()); } The code in WrapperCampaign Entity looks like this @OneToMany(mappedBy="campaign") public Set<WrapperTextAd> getTextAds() { return this.textads; }

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  • Openning an App on click of link in email in android?

    - by Amit
    I have a strange requirement for my project.. Suppose I have an app say XYZ installed in an android phone and than I receive an email from the mail server which contains a link like http://XYZ.com/?params(i.e. X=1&Y=2&Z=3) now on click of this link I want to open the XYZ app if it is installed in the phone and in the Activity I would like to get these parameters X,Y and Z and if the app is not installed user should be redirected to play store for downloading XYZ app and after installation app takes charge and behaves as if it was already installed (Opening the first activity with those parameters). How can I achieve that ? I have no idea where to start so even the smallest pointer in right direction will be of great help.

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  • typedef resolution rule

    - by kumar_m_kiran
    Hi All, Can you Please tell me the resolution rule involved in resolving the meaning of the variable in a typedef. Any link related to the same will be very useful. Example #typedef string* pstring; const pstring parr; Here confusion arises whether const'ness is for pointer or the content. Now based on what thumb rule do can we start resolving the above interpretation of the pstring?. Smilarly, If I have a very complex typedef'ed variable, like #typedef void (func*)()(int), I should be able to resolve it using the thumb rule. Thanks in advance for your suggestions

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  • Boost singleton and undefined reference

    - by Ockonal
    Hello, I globally use singleton pattern in my project. To make it easier - boost::singleton. Current project uses Ogre3d library for rendering. Here is some class: class GraphicSystem : public singleton<GraphicSystem> { private: Ogre::RenderWindow *mWindow; public: Ogre::RenderWindow *getWindow() const { return mWindow; } }; In GraphicSystem constructor I fill the mWindow value: mWindow = mRoot->createRenderWindow(...); I cheked it, everything makes normally. So, now I have to use handler for the window in input system (to get window handle). Somewhere else in another class: Ogre::RenderWindow *temp = GraphicSystem::get_mutable_instance().getWindow(); GraphicSystem::get_mutable_instance().getWindow()->getCustomAttribute("WINDOW", &mWindowHandle); temp is 0x00, and there is segfault at last line (getting custon attribute). I can't understand, why does singleton returns undefined pointer for the window. All another singleton-based classes work well.

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  • Can I use memcpy in C++ to copy classes that have no pointers or virtual functions

    - by Shane MacLaughlin
    Say I have a class, something like the following; class MyClass { public: MyClass(); int a,b,c; double x,y,z; }; #define PageSize 1000000 MyClass Array1[PageSize],Array2[PageSize]; If my class has not pointers or virtual methods, is it safe to use the following? memcpy(Array1,Array2,PageSize*sizeof(MyClass)); The reason I ask, is that I'm dealing with very large collections of paged data, as decribed here, where performance is critical, and memcpy offers significant performance advantages over iterative assignment. I suspect it should be ok, as the 'this' pointer is an implicit parameter rather than anything stored, but are there any other hidden nasties I should be aware of?

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  • AS2: How do I swapDepth of a Shape and a TextField?

    - by Alex Jordan
    AS2 this.createTextField("lbl_txt", this.getNextHighestDepth(), 70, 5, 150, 30) lbl_txt.autoSize = true; lbl_txt.text = "Hello"; var fmt:TextFormat = new TextFormat(); fmt.bold = true; fmt.color = 0x000000; fmt.underline = true; fmt.font = "Arial"; lbl_txt.setTextFormat(fmt); Timeline Layers action button_layer (button_layer is a animation on rollOver) arrow background Desired Result button_layer and action to be topmost layers and cursor to remain a pointer and not switch to text cursor on rollOver. action button_layer arrow lbl_txt (TextField created by AS) background

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  • "Cannot use fixed local inside lambda expression"

    - by JulianR
    I have an XNA 3.0 project that compiled just fine in VS2008, but that gives compile errors in VS2010 (with XNA 4.0 CTP). The error: Cannot use fixed local 'depthPtr' inside an anonymous method, lambda expression, or query expression depthPtr is a fixed float* into an array, that is used inside a Parallel.For lambda expression from System.Threading. As I said, this compiled and ran just fine on VS2008, but it does not on VS2010, even when targeting .NET 3.5. Has this changed in .NET 4.0, and even so, shouldn't it still compile when I choose .NET 3.5 as the target framework? Searching for the term "Cannot use fixed local" yields exactly one (useless) result, both in Google and Bing. If this has changed, what is the reason for this? I can imagine capturing a fixed pointer-type in a closure could get a bit weird, is that why? So I'm guessing this is bad practice? And before anyone asks: no, the use of pointers is not absolutely critical here. I would still like to know though :)

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  • How to make an NSURL that contains a | (pipe character)?

    - by aks
    Hi all, I am trying to access google maps' forward geocoding service from my iphone app. When i try to make an NSURL from a string with a pipe in it I just get a nil pointer. NSURL *searchURL = [NSURL URLWithString:@"http://maps.google.com/maps/api/geocode/json?address=6th+and+pine&bounds=37.331689,-122.030731|37.331689,-122.030731&sensor=false"]; I dont see any other way in the google api to send bounds coordinates with out a pipe. Any ideas about how I can do this?

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  • CSS menu is flickering when scrolling through it with hover effects

    - by kritop
    I hope i described the problem well!? You can see it here: http://dealmob.de/index_dev.html when u hover over the menu up and down fast u see the that its not staying, insteads its flickering like you would change the margins/paddings by few pixels. Any advice on how to solve this problem? thanks a lot like requested: #topcities { float:right; } #topcities li { padding-left:5px; width:100px; } #topcities li:hover { cursor:pointer; color:#000; background: url(images/hover_menue_back.jpg) repeat-x #FFF; -moz-border-radius: 5px; -webkit-border-radius: 5px; border:grey 1px solid; width:100px; }

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  • Unable to get Processor Speed in Device

    - by mukesh
    Hi i am using QueryperformanceFrequency to get the No of cycle i.e processor speed. But it is showing me the wornd value. It is written in the specicfication is the Processor is about 400MHz, but what we aregetting through code is something 16MHz. Please porvide any pointer : The code for Wince device is: enter code here LARGE_INTEGER FrequnecyCounter; QueryPerformanceFrequency(&FrequnecyCounter); CString temp; temp.Format(L"%lld",FrequnecyCounter.QuadPart)`AfxMessageBox(temp); Thanks, Mukesh

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