Search Results

Search found 3592 results on 144 pages for 'pointer'.

Page 121/144 | < Previous Page | 117 118 119 120 121 122 123 124 125 126 127 128 | Next Page >

Multi-reader IPC solution?

- by gct

I'm working on a framework in C++ (just for fun for now), that lets the user write plugins that use a standard API to stream data between each other. There's going to be three basic transport mechanisms for the data: files, sockets, and some kind of IPC piping system. The system is set up so that for the non-file transport, each stream can have multiple readers. IE once a server socket it setup, multiple computers can connect and stream the data. I'm a little stuck at the multi-reader IPC system though. All my plugins run in threads so they live in the same address space, so some kind of shared memory system would work fine, I was thinking I'd write my own circular buffer with a write pointer and read pointers chassing it around the buffer, but I have my doubts that I can achieve the same performance as something like linux pipes. I'm curious what people would suggest for a multi-reader solution to something like this? Is the overhead for pipes or domain sockets low enough that I could just open a connection to each reader and issue separate writes to each reader? This is intended to be significant volumes of data (tens of mega-samples/sec), so performance is a must.

Read the article
CSS style submit like href tag

- by seth.vargo

Hi all, I have a button class that I wrote in CSS. It essentially displays block, adds some styles, etc. Whenever I add the class to a tags, it works fine - the a tag spans the entire width of its container like display:block should do... However, when I add the button class to an input button, Chrome, Safari, and Firefox all add a margin-right: 3px... I've used the DOM inspector in both Chrome and Safari and NO WHERE should it be adding a extra 3px padding. I tried adding margin: 0 !important; and/or margin-right: 0 !important to my button class in my CSS, but the browser STILL renders a 3px right margin! Is this a known issue, and is there a CSS-based solution (i.e. not jQuery/javascript) CODE FOLLOWS: .button { position: relative; display: block; margin: 0; border: 1px solid #369; color: #fff; font-weight: bold; padding: 11px 20px; line-height: 18px; text-align: center; text-transform: uppercase; cursor: hand; cursor: pointer; }

Read the article
Write to memory buffer instead of file with libjpeg?

- by Richard Knop

I have found this function which uses libjpeg to write to a file: int write_jpeg_file( char *filename ) { struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; /* this is a pointer to one row of image data */ JSAMPROW row_pointer[1]; FILE *outfile = fopen( filename, "wb" ); if ( !outfile ) { printf("Error opening output jpeg file %s\n!", filename ); return -1; } cinfo.err = jpeg_std_error( &jerr ); jpeg_create_compress(&cinfo); jpeg_stdio_dest(&cinfo, outfile); /* Setting the parameters of the output file here */ cinfo.image_width = width; cinfo.image_height = height; cinfo.input_components = bytes_per_pixel; cinfo.in_color_space = color_space; /* default compression parameters, we shouldn't be worried about these */ jpeg_set_defaults( &cinfo ); /* Now do the compression .. */ jpeg_start_compress( &cinfo, TRUE ); /* like reading a file, this time write one row at a time */ while( cinfo.next_scanline < cinfo.image_height ) { row_pointer[0] = &raw_image[ cinfo.next_scanline * cinfo.image_width * cinfo.input_components]; jpeg_write_scanlines( &cinfo, row_pointer, 1 ); } /* similar to read file, clean up after we're done compressing */ jpeg_finish_compress( &cinfo ); jpeg_destroy_compress( &cinfo ); fclose( outfile ); /* success code is 1! */ return 1; } I would actually need to write the jpeg compressed image just to memory buffer, without saving it to a file, to save time. Could somebody give me an example how to do it? I have been searching the web for a while but the documentation is very rare if any and examples are also difficult to come by.

Read the article
How is external memory, internal memory, and cache organized?

- by goldenmean

Consider a system as follows:= A hardware board having say ARM Cortex-A8 and Neon Vector coprocessor, and Embedded Linux OS running on Cortex-A8. On this environment, if there is some application - say, a video decoder is executing - then: How is it decided that which buffers would be in external memory, which ones would be allocated in internal SRAM, etc. When one says calloc/malloc on such system/code, the pointer returned is from which memory: internal or external? Can a user make buffers to be allocated to the memories of his choice (internal/external)? In ARM architectures, there is another memory called as Tightly coupled memory (TCM). What is that and how can user enable and use it? Can I declare buffers in this memory? Do I need to see the memory map (if any) of the hardware board to understand about all these different physical memories present in a typical hardware board? How much of a role does the OS play in distinguishing these different memories? Sorry for multiple questions, but i think they all are interlinked.

Read the article
Returning pointers in a thread-safe way.

- by Roddy

Assume I have a thread-safe collection of Things (call it a ThingList), and I want to add the following function. Thing * ThingList::findByName(string name) { return &item[name]; // or something similar.. } But by doing this, I've delegated the responsibility for thread safety to the calling code, which would have to do something like this: try { list.lock(); // NEEDED FOR THREAD SAFETY Thing *foo = list.findByName("wibble"); foo->Bar = 123; list.unlock(); } catch (...) { list.unlock(); throw; } Obviously a RAII lock/unlock object would simplify/remove the try/catch/unlocks, but it's still easy for the caller to forget. There are a few alternatives I've looked at: Return Thing by value, instead of a pointer - fine unless you need to modify the Thing Add function ThingList::setItemBar(string name, int value) - fine, but these tend to proliferate Return a pointerlike object which locks the list on creation and unlocks it again on destruction. Not sure if this is good/bad practice... What's the right approach to dealing with this?

Read the article
Modelling in Agile Development

- by bertzzie

I'm writing a bachelor dissertation report where I'm developing a system with Agile methodology. Given that the development is an one man show, of course the "Agile" I did was not really agile at all (from my understanding at least). So I want some perspective from SO crowds, who is of course a professional, real world, developer with tons of experience. I think real world experience is better than the theory and experiments that I did. My question is: Do we model during development time when using Agile? UML? DFD? Or a Functional Specification is enough1? If modelling is not really necessary, what do we use to communicate to the user, as the user almost always won't understand UML or DFD? For my system, I use UI & UX Design with heavy prototyping, but then I don't have time to draw UML any more. Which one is better? 1 http://www.joelonsoftware.com/articles/fog0000000036.html I hope the question's not "subjective and argumentative" as I know this question exist because of my lack of understanding in the agile development. If it is, could someone just give me a pointer or reference about that? Possible duplicate: Do you use UML in Agile development practices?

Read the article
[C++][OpenMP] Proper use of "atomic directive" to lock STL container

- by conradlee

I have a large number of sets of integers, which I have, in turn, put into a vector of pointers. I need to be able to update these sets of integers in parallel without causing a race condition. More specifically. I am using OpenMP's "parallel for" construct. For dealing with shared resources, OpenMP offers a handy "atomic directive," which allows one to avoid a race condition on a specific piece of memory without using locks. It would be convenient if I could use the "atomic directive" to prevent simultaneous updating to my integer sets, however, I'm not sure whether this is possible. Basically, I want to know whether the following code could lead to a race condition vector< set<int>* > membershipDirectory(numSets, new set<int>); #pragma omp for schedule(guided,expandChunksize) for(int i=0; i<100; i++) { set<int>* sp = membershipDirectory[5]; #pragma omp atomic sp->insert(45); } (Apologies for any syntax errors in the code---I hope you get the point) I have seen a similar example of this for incrementing an integer, but I'm not sure whether it works when working with a pointer to a container as in my case.

Read the article
How to store an interger value of 4 bytes in a memory of chunk which is malloced as type char

- by Adi

Dear all, Hello Guys!! This is my first post in the forum . I am really looking forward to having good fun in this site. My question is : int mem_size = 10; char *start_ptr; if((start_ptr= malloc(mem_size*1024*1024*sizeof(char)))==NULL) {return -1;} I have allocated a chunk of memory of type char and size is say 10 MB (i.e mem_size = 10 ); Now I want to store the size information in the header of the memory chunk, To make myself more clear Lets Say : start_ptr = 0xaf868004 (This is the value I got from my execution, it changes every time) Now I want to put the size information in the start of this pointer.. i.e *start_ptr = mem_size*1024*1024; But I am not able to put this information in the start_ptr. I think the reason is because my ptr is of type char which only takes one byte but I am trying to store int which takes 4 bytes, is the problem . I am not sure how to fix this problem.. I would greatly appreciate your suggestions. Cheers!! Aditya

Read the article
Documentation about difference between javacript src and javascript library in grails

- by damian

I know that if you write in a view: <g:javascript src="myscript.js" /> <g:javascript src="myscript.js" /> <g:javascript src="myscript.js" />  <g:javascript library="myscript" /> <g:javascript library="myscript" /> <g:javascript library="myscript" /> It will out output: <script type="text/javascript" src="/vip/js/myscript.js"></script> <script type="text/javascript" src="/vip/js/myscript.js"></script> <script type="text/javascript" src="/vip/js/myscript.js"></script>  <script type="text/javascript" src="/vip/js/myscript.js"></script> Conclution: with library it will try to include only once. I have been try to find documentation about it without success. Do you have any pointer?

Read the article
Jquery drag /drop and clone

- by Sajeev

Hi I need to achive this .. I have a set of droppable items ( basically I am droping designs on a apparel ) and I am dropping a clone.. If I don't like the dropped object (designs) - I want to delete that by doing something like hidden . But I am unable to do that. Please help me.. here is the code var clone; $(document).ready(function(){ $(".items").draggable({helper: 'clone',cursor: 'hand'}); $(".droparea").droppable({ accept: ".items", hoverClass: 'dropareahover', tolerance: 'pointer', drop: function(ev, ui) { var dropElemId = ui.draggable.attr("id"); var dropElem = ui.draggable.html(); clone = $(dropElem).clone(); // clone it and hold onto the jquery object clone.id="newId"; clone.css("position", "absolute"); clone.css("top", ui.absolutePosition.top); clone.css("left", ui.absolutePosition.left); clone.draggable({ containment: 'parent' ,cursor: 'crosshair'}); $(this).append(clone); alert("done dragging "); /lets assume I have a delete button when I click that clone should dissapear so that I can drop another design - but the following code has no effect //and the item is still visible , how to make it dissapear ? $('#newId').css("visibility","hidden"); } }); });

Read the article
How to pass data to a C++0x lambda function that will run in a different thread?

- by Dimitri C.

In our company we've written a library function to call a function asynchronously in a separate thread. It works using a combination of inheritance and template magic. The client code looks as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, &DemoThread::SomeFunction, stringToPassByValue); Since the introduction of lambda functions I'd like to use it in combination with lambda functions. I'd like to write the following client code: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=]() { const std::string someCopy = stringToPassByValue; }); Now, with the Visual C++ 2010 this code doesn't work. What happens is that the stringToPassByValue is not copied. Instead the "capture by value" feature passes the data by reference. The result is that if the function is executed after stringToPassByValue has gone out of scope, the application crashes as its destructor is called already. So I wonder: is it possible to pass data to a lambda function as a copy? Note: One possible solution would be to modify our framework to pass the data in the lambda parameter declaration list, as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=](const std::string stringPassedByValue) { const std::string someCopy = stringPassedByValue; } , stringToPassByValue); However, this solution is so verbose that our original function pointer solution is both shorter and easier to read. Update: The full implementation of AsyncCall is too big to post here. In short, what happens is that the AsyncCall template function instantiates a template class holding the lambda function. This class is derived from a base class that contains a virtual Execute() function, and upon an AsyncCall() call, the function call class is put on a call queue. A different thread then executes the queued calls by calling the virtual Execute() function, which is polymorphically dispatched to the template class which then executes the lambda function.

Read the article
Java abstract visitor - guarantueed to succeed? If so, why?

- by disown

I was dealing with hibernate, trying to figure out the run-time class behind proxied instances by using the visitor pattern. I then came up with an AbstractVisitable approach, but I wonder if it will always produce correct results. Consider the following code: interface Visitable { public void accept(Visitor v); } interface Visitor { public void visit(Visitable visitorHost); } abstract class AbstractVisitable implements Visitable { @Override public void accept(Visitor v) { v.visit(this); } } class ConcreteVisitable extends AbstractVisitable { public static void main(String[] args) { final Visitable visitable = new ConcreteVisitable(); final Visitable proxyVisitable = (Visitable) Proxy.newProxyInstance( Thread.currentThread().getContextClassLoader(), new Class<?>[] { Visitable.class }, new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { return method.invoke(visitable, args); } }); proxyVisitable.accept(new Visitor() { @Override public void visit(Visitable visitorHost) { System.out.println(visitorHost.getClass()); } }); } } This makes a ConcreteVisitable which inherits the accept method from AbstractVisitable. In c++, I would consider this risky, since this in AbstractVisitable could be referencing to AbstractVisitable::this, and not ConcreteVisitable::this. I was worried that the code under certain circumstances would print class AbstractVisible. Yet the code above outputs class ConcreteVisitable, even though I hid the real type behind a dynamic proxy (the most difficult case I could come up with). Is the abstract visitor approach above guaranteed to work, or are there some pitfalls with this approach? What guarantees are given in Java with respect to the this pointer?

Read the article
open Fancybox in tabs

- by Prashant

Hello all. I am using PHP + jQuery + Fancybox in my project. I have multiple tabs that get created dynamically. I have got a star icon on every tab header and on clicking them I want to open a fancybox. My tabs are basically ul-li with following dynamic code. $("#tabs").append("<li class='current'><a class='tab' id='tab_" + tabCnt + "<a href='#loginBox_div' class='login_link'> <img src='star.png' style='cursor:pointer'/> </a>" + "<a href='javascript:void(0);' class='remove'>x</a></li>"); in my index file : $(document).ready(function() { $("a.login_link").fancybox({ 'titlePosition' : 'inside', 'transitionIn' : 'none', 'transitionOut' : 'none' }); }); The problem is that when I click on star icon of first tab, the loginBox_div (fancybox) opens properly. But when my second tab is created and when I click on its star icon, the fancybox is not opening although the class is applied in second and successive tabs. No javascript errors too. Please show me the way. Thank you.

Read the article
How to get address of va_arg?

- by lionbest

I hack some old C API and i got a compile error with the following code: void OP_Exec( OP* op , ... ) { int i; va_list vl; va_start(vl,op); for( i = 0; i < op->param_count; ++i ) { switch( op->param_type[i] ) { case OP_PCHAR: op->param_buffer[i] = va_arg(vl,char*); // ok it works break; case OP_INT: op->param_buffer[i] = &va_arg(vl,int); // error here break; // ... more here } } op->pexec(op); va_end(vl); } The error with gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu9) was: main.c|55|error: lvalue required as unary ‘&’ operand So why exactly it's not possible here to get a pointer to argument? How to fix it? This code is executed very often with different OP*, so i prefer to not allocate extra memory. Is it possible to iterate over va_list knowing only the size of arguments?

Read the article
why BOOST_FOREACH cannot handle const boost::ptr_map?

- by psaghelyi

void main() { typedef boost::ptr_map<int, char> MyMap; MyMap mymap; mymap[1] = 'a'; mymap[2] = 'b'; mymap[3] = 'c'; BOOST_FOREACH(MyMap::value_type value, mymap) { std::cout << value.first << " " << value.second << std::endl; } MyMap const & const_mymap = mymap; BOOST_FOREACH(MyMap::value_type value, const_mymap) { std::cout << value.first << " " << value.second << std::endl; } } The following error message comes from GCC at the second BOOST_FOREACH error: conversion from 'boost::ptr_container_detail::ref_pair<int, const char* const>' to non-scalar type 'boost::ptr_container_detail::ref_pair<int, char* const>' requested I reckon that this is the weakness of the pointer container's ref_pair...

Read the article
Apples, oranges, and pointers to the most derived c++ class

- by Matthew Lowe

Suppose I have a bunch of fruit: class Fruit { ... }; class Apple : public Fruit { ... }; class Orange: public Fruit { ... }; And some polymorphic functions that operate on said fruit: void Eat(Fruit* f, Pesticide* p) { } void Eat(Apple* f, Pesticide* p) { ingest(f,p); } void Eat(Orange* f, Pesticide* p) { peel(f,p); ingest(f,p); } OK, wait. Stop right there. Note at this point that any sane person would make Eat() a virtual member function of the Fruit classes. But that's not an option, because I am not a sane person. Also, I don't want that Pesticide* in the header file for my fruit class. Sadly, what I want to be able to do next is exactly what member functions and dynamic binding allow: typedef list<Fruit*> Fruits; Fruits fs; ... for(Fruits::iterator i=fs.begin(), e=fs.end(); i!=e; ++i) Eat(*i); And obviously, the problem here is that the pointer we pass to Eat() will be a Fruit*, not an Apple* or an Orange*, therefore nothing will get eaten and we will all be very hungry. So what I really want to be able to do instead of this: Eat(*i); is this: Eat(MAGIC_CAST_TO_MOST_DERIVED_CLASS(*i)); But to my limited knowledge, such magic does not exist, except possibly in the form of a big nasty if-statement full of calls to dynamic_cast. So is there some run-time magic of which I am not aware? Or should I implement and maintain a big nasty if-statement full of dynamic_casts? Or should I suck it up, quit thinking about how I would implement this in Ruby, and allow a little Pesticide to make its way into my fruit header?

Read the article
MFC/CCriticalSection: Simple lock situation hangs

- by raph.amiard

I have to program a simple threaded program with MFC/C++ for a uni assignment. I have a simple scenario in wich i have a worked thread which executes a function along the lines of : UINT createSchedules(LPVOID param) { genProgThreadVal* v = (genProgThreadVal*) param; // v->searcherLock is of type CcriticalSection* while(1) { if(v->searcherLock->Lock()) { //do the stuff, access shared object , exit clause etc.. v->searcherLock->Unlock(); } } PostMessage(v->hwnd, WM_USER_THREAD_FINISHED , 0,0); delete v; return 0; } In my main UI class, i have a CListControl that i want to be able to access the shared object (of type std::List). Hence the locking stuff. So this CList has an handler function looking like this : void Ccreationprogramme::OnLvnItemchangedList5(NMHDR *pNMHDR, LRESULT *pResult) { LPNMLISTVIEW pNMLV = reinterpret_cast<LPNMLISTVIEW>(pNMHDR); if((pNMLV->uChanged & LVIF_STATE) && (pNMLV->uNewState & LVNI_SELECTED)) { searcherLock.Lock(); // do the stuff on shared object searcherLock.Unlock(); // do some more stuff } *pResult = 0; } The searcherLock in both function is the same object. The worker thread function is passed a pointer to the CCriticalSection object, which is a member of my dialog class. Everything works but, as soon as i do click on my list, and so triggers the handler function, the whole program hangs indefinitely.I tried using a Cmutex. I tried using a CSingleLock wrapping over the critical section object, and none of this has worked. What am i missing ?

Read the article
How to get at JSON in grails 2.0

- by Mikey

I am sending myself JSON like so with jQuery: $.ajax ({ type: "POST", url: 'http://localhost:8080/myproject/myController/myAction', dataType: 'json', async: false, //json object to sent to the authentication url data: {"stuff":"yes", "listThing":[1,2,3], "listObjects":[{"one":"thing"},{"two":"thing2"}]}, success: function () { alert("Thanks!"); } }) I send this to a controller and do println params And I know I'm already in trouble... [stuff:yes, listObjects[1][two]:thing2, listObjects[0][one]:thing, listThing[]:[1, 2, 3], action:myAction, controller:myController] I cannot figure out how to get at most of these values... I can get "yes" with params.stuff, but I cant do params.listThing.each{} or params.listObjects.each{} What am I doing wrong? UPDATE: I make the controller do this to try the two suggestions so far: println params println params.stuff println params.list('listObjects') println params.listThing def thisWontWork = JSON.parse(params.listThing) render("omg l2json") look how weird the parameters look at the end of the null pointer exception when I try the answers: [stuff:yes, listObjects[1][two]:thing2, listObjects[0][one]:thing, listThing[]:[1, 2, 3], action:l2json, controller:rateAPI] yes [] null | Error 2012-03-25 22:16:13,950 ["http-bio-8080"-exec-7] ERROR errors.GrailsExceptionResolver - NullPointerException occurred when processing request: [POST] /myproject/myController/myAction - parameters: stuff: yes listObjects[1][two]: thing2 listObjects[0][one]: thing listThing[]: 1 listThing[]: 2 listThing[]: 3 UPDATE 2 I am learning things, but this can't be right: println params['listThing[]'] println params['listObjects[0][one]'] prints [1, 2, 3] thing It seems like this is some part of grails new JSON marshaling. This is somewhat inconvenient for my purposes of hacking around with the values. How would I get all these individual params back into a big groovy object of nested maps and lists? Maybe I am not doing what I want with jQuery?

Read the article
grailsApplication access in Grails unit Test

- by Reza

I am trying to write unit tests for a service which use grailsApplication.config to do some settings. It seems that in my unit tests that service instance could not access the config file (null pointer) for its setting while it could access that setting when I run "run-app". How could I configure the service to access grailsApplication service in my unit tests. class MapCloudMediaServerControllerTests { def grailsApplication @Before public void setUp(){ grailsApplication.config= ''' video{ location="C:\\tmp\\" // or shared filesystem drive for a cluster yamdi{ path="C:\\FFmpeg\\ffmpeg-20121125-git-26c531c-win64-static\\bin\\yamdi" } ffmpeg { fileExtension = "flv" // use flv or mp4 conversionArgs = "-b 600k -r 24 -ar 22050 -ab 96k" path="C:\\FFmpeg\\ffmpeg-20121125-git-26c531c-win64-static\\bin\\ffmpeg" makethumb = "-an -ss 00:00:03 -an -r 2 -vframes 1 -y -f mjpeg" } ffprobe { path="C:\\FFmpeg\\ffmpeg-20121125-git-26c531c-win64-static\\bin\\ffprobe" params="" } flowplayer { version = "3.1.2" } swfobject { version = "" qtfaststart { path= "C:\\FFmpeg\\ffmpeg-20121125-git-26c531c-win64-static\\bin\\qtfaststart" } } ''' } @Test void testMpegtoFlvConvertor() { log.info "In test Mpg to Flv Convertor function!" def controller=new MapCloudMediaServerController() assert controller!=null controller.videoService=new VideoService() assert controller.videoService!=null log.info "Is the video service null? ${controller.videoService==null}" controller.videoService.grailsApplication=grailsApplication log.info "Is grailsApplication null? ${controller.videoService.grailsApplication==null}" //Very important part for simulating the HTTP request controller.metaClass.request = new MockMultipartHttpServletRequest() controller.request.contentType="video/mpg" controller.request.content= new File("..\\MapCloudMediaServer\\web-app\\videoclips\\sample3.mpg").getBytes() controller.mpegtoFlvConvertor() byte[] videoOut=IOUtils.toByteArray(controller.response.getOutputStream()) def outputFile=new File("..\\MapCloudMediaServer\\web-app\\videoclips\\testsample3.flv") outputFile.append(videoOut) } }

Read the article
Getting ellipses function parameters without an initial argument

- by Tox1k

So I've been making a custom parser for a scripting language, and I wanted to be able to pass only ellipses arguments. I don't need or want an initial variable, however Microsoft and C seem to want something else. FYI, see bottom for info. I've looked at the va_* definitions #define _crt_va_start(ap,v) ( ap = (va_list)_ADDRESSOF(v) + _INTSIZEOF(v) ) #define _crt_va_arg(ap,t) ( *(t *)((ap += _INTSIZEOF(t)) - _INTSIZEOF(t)) ) #define _crt_va_end(ap) ( ap = (va_list)0 ) and the part I don't want is the v in va_start. As a little background I'm competent in goasm and I know how the stack works so I know what's happening here. I was wondering if there is a way to get the function stack base without having to use inline assembly. Ideas I've had: #define im_va_start(ap) (__asm { mov [ap], ebp }) and etc... but really I feel like that's messy and I'm doing it wrong. struct function_table { const char* fname; (void)(*fptr)(...); unsigned char maxArgs; }; function_table mytable[] = { { "MessageBox", &tMessageBoxA, 4 } }; ... some function that sorts through a const char* passed to it to find the matching function in mytable and calls tMessageBoxA with the params. Also, the maxArgs argument is just so I can check that a valid number of parameters is being sent. I have personal reasons for not wanting to send it in the function, but in the meantime we can just say it's because I'm curious. This is just an example; custom libraries are what I would be implementing so it wouldn't just be calling WinAPI stuff. void tMessageBoxA(...) { // stuff to load args passed MessageBoxA(arg1, arg2, arg3, arg4); } I'm using the __cdecl calling convention and I've looked up ways to reliably get a pointer to the base of the stack (not the top) but I can't seem to find any. Also, I'm not worried about function security or typechecking.

Read the article
android opengl es texture mapping into polygons

- by kamil

I wrote opengl es code for android to map textures on a square but i want to draw texture on polygons. When user moved the image, texture will be mapped on polygons have more vertexes. I tried the arrays combination below for pentagon but i could not find the correct triangle combination in indices array. public float vertices[] = { // -1.0f, 1.0f, 0.0f, //Top Left // -1.0f, -1.0f, 0.0f, //Bottom Left // 1.0f, -1.0f, 0.0f, //Bottom Right // 1.0f, 1.0f, 0.0f //Top Right -1.0f, 1.0f, 0.0f, //Top Left -1.0f, -1.0f, 0.0f, //Bottom Left 1.0f, -1.0f, 0.0f, //Bottom Right 1.0f, 1.0f, 0.0f, //Top Right 0.4f, 1.4f, 0.0f }; /** Our texture pointer */ private int[] textures = new int[1]; /** The initial texture coordinates (u, v) */ private float texture[] = { //Mapping coordinates for the vertices // 1.0f, 0.0f, // 1.0f, 1.0f, // 0.0f, 1.0f, // 0.0f, 0.0f, // 0.0f, 1.0f, // 0.0f, 0.0f, // 1.0f, 0.0f, // 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.7f, }; /** The initial indices definition */ private byte indices[] = { //2 triangles // 0,1,2, 2,3,0, 0,1,2, 2,3,4, 3,4,0, //triangles for five vertexes }; i draw with the code below gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer);

Read the article
Behavior difference between UIView.subviews and [NSView subviews]

- by zpasternack

I have a piece of code in an iPhone app, which removes all subviews from a UIView subclass. It looks like this: NSArray* subViews = self.subviews; for( UIView *aView in subViews ) { [aView removeFromSuperview]; } This works fine. In fact, I never really gave it much thought until I tried nearly the same thing in a Mac OS X app (from an NSView subclass): NSArray* subViews = [self subviews]; for( NSView *aView in subViews ) { [aView removeFromSuperview]; } That totally doesn’t work. Specifically, at runtime, I get this: *** Collection <NSCFArray: 0x1005208a0> was mutated while being enumerated. I ended up doing it like so: NSArray* subViews = [[self subviews] copy]; for( NSView *aView in subViews ) { [aView removeFromSuperview]; } [subViews release]; That's fine. What’s bugging me, though, is why does it work on the iPhone? subviews is a copy property: @property(nonatomic,readonly,copy) NSArray *subviews; My first thought was, maybe @synthesize’d getters return a copy when the copy attribute is specified. The doc is clear on the semantics of copy for setters, but doesn’t appear to say either way for getters (or at least, it’s not apparent to me). And actually, doing a few tests of my own, this clearly does not seem to be the case. Which is good, I think returning a copy would be problematic, for a few reasons. So the question is: how does the above code work on the iPhone? NSView is clearly returning a pointer to the actual array of subviews, and perhaps UIView isn’t. Perhaps it’s simply an implementation detail of UIView, and I shouldn’t get worked up about it. Can anyone offer any insight?

Read the article
Accessing program information that gdb sees in C++

- by anon

I have a program written in C++, on Linux, compiled with -g. When I run it under gdb, I can 1) set breakpoints 2) at those breakpoints, print out variables 3) see the stackframe 4) given a variable that's a structure, print out parts of the structure (i.e. how ddd displays information). Now, given that my program is compiled with "-g" -- is there anyway that I can access this power within my program itself? I.e. given that my program is compiled with "-g", is there some std::vector<string> getStackFrame(); function I can call to get the current stackframe at the current point of execution? Given a pointer to an object and it's type ... can I do std::vector getClassMember(class_name); ? I realize the default answer is "no, C++ doesn't support that level of introspection" -- however, recall I'm on linux, my program is compiled with "-g", and gdb can do it, so clearly the inforamtion is there. Question is: is there some API for accessing it? EDIT: PS Naysers, I'd love to see a reason for closing this question.

Read the article
How to DRY on CRUD parts of my Rails app?

- by kolrie

I am writing an app which - similarly to many apps out there - is 90% regular CRUD things and 10% "juice", where we need nasty business logic and more flexibility and customization. Regarding this 90%, I was trying to stick to the DRY principle as much as I can. As long as controllers go, I have found resource_controller to really work, and I could get rid of all the controllers on that area, replacing them with a generic one. Now I'd like to know how to get the same with the views. On this app I have an overall, application.html.erb layout and then I must have another layout layer, common for all CRUD views and finally a "core" part: On index.html.erb all I need to generate a simple table with the fields and labels I indicate. For new and edit, also generic form edition, indicating labels and fields (with a possibility of providing custom fields if needed). I am not sure I will need show, but if I do it would be the same as new and edit. What plugins and tools (or even articles and general pointer) would help me to get that done? Thanks, Felipe.

Read the article
Is this 2D array initialization a bad idea?

- by Brendan Long

I have something I need a 2D array for, but for better cache performance, I'd rather have it actually be a normal array. Here's the idea I had but I don't know if it's a terrible idea: const int XWIDTH = 10, YWIDTH = 10; int main(){ int * tempInts = new int[XWIDTH * YWIDTH]; int ** ints = new int*[XWIDTH]; for(int i=0; i<XWIDTH; i++){ ints[i] = &tempInts[i*YWIDTH]; } // do things with ints delete[] ints[0]; delete[] ints; return 0; } So the idea is that instead of newing a bunch of arrays (and having them placed in different places in memory), I just point to an array I made all at once. The reason for the delete[] (int*) ints; is because I'm actually doing this in a class and it would save [trivial amounts of] memory to not save the original pointer. Just wondering if there's any reasons this is a horrible idea. Or if there's an easier/better way. The goal is to be able to access the array as ints[x][y] rather than ints[x*YWIDTH+y].

Read the article

< Previous Page | 117 118 119 120 121 122 123 124 125 126 127 128 | Next Page >