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  • Why does a delegate with no parameters compile?

    - by Ryan
    I'm confused why this compiles: private delegate int MyDelegate(int p1, int p2); private void testDelegate() { MyDelegate imp = delegate { return 1; }; } MyDelegate should be a pointer to a method that takes two int parameters and returns another int, right? Why am I allowed to assign a method that takes no parameters? Interestingly, these doesn't compile (it complains about the signature mismatches, as I'd expect) private void testDelegate() { // Missing param MyDelegate imp = delegate(int p1) { return 1; }; // Wrong return type MyDelegate imp2 = delegate(int p1, int p2) { return "String"; }; } Thanks for any help! Ryan

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  • Drupal: Programmatically saving imagefield images

    - by Ace
    Hey there! I'm trying to write a sync function that saves some data to nodes, which works fine, until I try to save the thumbnail image associated with the node. I've managed to download the file and put it in my sites/default/files folder, but what's the best way to tell Drupal, "put this file in that CCK imagefield"? EDIT To clarify a bit.. I sync the thumbnails separately (since one image can be used by several nodes)... I would like the initial thumbnail sync to save the files in the correct folder (not a temp one) and just point the imagefield to this file... That's what annoys me with field_file_save_file(), it saves a new file instead of just making a pointer.. Any advice?

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  • Array of char *

    - by user353060
    Hello, I am having problems with array pointers. I've looked through Google and my attempts are futile so far. What I would like to do is, I have a char name[256]. I will be 10 of those. Hence, I would need to keep track of each of them by pointers. Trying to create a pointer to them. int main() { char superman[256] = "superman"; char batman[256] = "batman"; char catman[256] = "catman"; char *names[10]; names[0] = superman; names[1] = batman; system("pause"); return 0; } How do I actually traverse an array of pointers?

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  • Objective C LValue required as unary '&' operand

    - by Bob
    Hello! In my code, I get this error when I try to get a pointer to my class property. (I wrote a small *.OBJ file translator in Python, discarding the normals) CODE: //line: line of text const char *str = [line UTF8String]; Point3D *p1, *p2, *p3; p1 = [Point3D makeX:0 Y:0 Z:0]; p2 = [Point3D makeX:0 Y:0 Z:0]; p3 = [Point3D makeX:0 Y:0 Z:0]; sscanf(str, "t %f,%f,%f %f,%f,%f %f,%f,%f",(&[p1 x]),&([p1 y]),&([p1 z]),&([p2 x]),&([p2 y]),&([p2 z]),&([p3 x]),&([p3 y]),&([p3 z])); Triangle3D *tri = [Triangle3D make:p1 p2:p2 p3:p3];

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  • Handle/Grip bar convention

    - by tomdemuyt
    Greetings, Because textarea elements do not resize with jquery.touch ( http://plugins.jquery.com/project/touch ), I've put an textarea in a table where the first row allows the user to drag the table around and resize it with the textarea growing/shrinking/moving along. It works well, except that users dont seem to 'get' that they can use the bar to resize/move. I was trying to find some 'grip bar' graphics but google isnt helping me. What is the best way to show users that an element can be moved/resized ? Pointer to graphics ( generators ) would be great. Or, does any one know how to make textarea's movable/resizable ? T.

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  • Reading in 4 bytes at a time

    - by alphomega
    I have a big file full of integers that I'm loading in. I've just started using C++, and I'm trying out the filestream stuff. From everything I've read, it appears I can only read in bytes, So I've had to set up a char array, and then cast it as a int pointer. Is there a way I can read in 4 bytes at a time, and eliminate the need for the char array? const int HRSIZE = 129951336; //The size of the table char bhr[HRSIZE]; //The table int *dwhr; int main() { ifstream fstr; /* load the handranks.dat file */ std::cout << "Loading table.dat...\n"; fstr.open("table.dat"); fstr.read(bhr, HRSIZE); fstr.close(); dwhr = (int *) bhr; }

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  • C optimization breaks algorithm

    - by Halpo
    I am programming an algorithm that contains 4 nested for loops. The problem is at at each level a pointer is updated. The innermost loop only uses 1 of the pointers. The algorithm does a complicated count. When I include a debugging statement that logs the combination of the indexes and the results of the count I get the correct answer. When the debugging statement is omitted, the count is incorrect. The program is compiled with the -O3 option on gcc. Why would this happen?

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  • A programming language for teaching data structures and algorithms with? [closed]

    - by Andreas Grech
    Possible Duplicate: Choice of programming language for learning data structures and algorithms Teachers have different opinions on what programming language they would choose to teach data structures and algorithms with. Some would prefer a lower level language such as C because it allows the student to learn more about what goes on beyond the abstractions in terms of memory allocation and deallocation and pointers and pointer arithmetic. On the other hand, others would say that they would prefer a higher level language like Java because it allows the student to learn more about the concepts of the structures and the algorithm design rather than 'waste time' and fiddle around with memory segmentation faults and all the blunders that come with languages where memory management is manual. What is your take on this issue? And also, please post any references you may know of that also discuss this argument.

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  • How does C++ free the memory when a constructor throws an exception and a custom new is used

    - by Joshua
    I see the following constructs: new X will free the memory if X constructor throws. operator new() can be overloaded. The canonical definition of an operator new overload is void *operator new(heap h) and the corrisponding operator delete. The most common operator new overload is pacement new, which is void *operator new(void *p) { return p; } You almost always cannot call delete on the pointer given to placement new. This leads to a single question. How is memory cleaned up when X constructor throws and an overloaded new is used?

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  • Double indirection and structures passed into a function

    - by ZPS
    I am curious why this code works: typedef struct test_struct { int id; } test_struct; void test_func(test_struct ** my_struct) { test_struct my_test_struct; my_test_struct.id=267; *my_struct = &my_test_struct; } int main () { test_struct * main_struct; test_func(&main_struct); printf("%d\n",main_struct->id); } This works, but pointing to the memory address of a functions local variable is a big no-no, right? But if i used a structure pointer and malloc, that would be the correct way, right? void test_func(test_struct ** my_struct) { test_struct *my_test_struct; my_test_struct = malloc(sizeof(test_struct)); my_test_struct->id=267; *my_struct = my_test_struct; } int main () { test_struct * main_struct; test_func(&main_struct); printf("%d\n",main_struct->id); }

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  • typedef declaration syntax

    - by mt_serg
    Some days ago I looked at boost sources and found interesting typedef. There is a code from "boost\detail\none_t.hpp": namespace boost { namespace detail { struct none_helper{}; typedef int none_helper::*none_t ; } // namespace detail } // namespace boost I didn't see syntax like that earlier and can't explain the sense of that. This typedef introduces name "none_t" as pointer to int in boost::detail namespace. What the syntax is? And what difference between "typedef int none_helper::*none_t" and for example "typedef int *none_t" ?

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  • SSL_CTX_set_cert_verify_callback vs. SSL_CTX_set_verify

    - by BreakPoint
    Hello, Can anyone tell me what is the difference between SSL_CTX_set_cert_verify_callback and SSL_CTX_set_verify? From OpenSSL docs: SSL_CTX_set_cert_verify_callback() sets the verification callback function for ctx. SSL objects that are created from ctx inherit the setting valid at the time when SSL_new(3) is called. and: SSL_CTX_set_verify() sets the verification flags for ctx to be mode and specifies the verify_callback function to be used. If no callback function shall be specified, the NULL pointer can be used for verify_callback. So I'm trying to understand which callback to send for each one (from client side). Thanks experts.

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  • What's void *userData exactly?

    - by mystify
    In a C function declaration, I have seen this parameter definition: void *userData so, what exactly is that? My guess: the void says it can be anything arbitrary, or even nothing. Almost similar to id of objective-c. It just allows to pass in whatever data structure you like. The star in front of userData says, that the argument must be passed in by reference. So when using this stuff in the function body, typically it must be casted and dereferenced. So if I pass in an pointer to SomeClass instance, I would get that like this: SomeClass *myObj = (SomeClass*)userData; In the case I had nothing special to pass along, I would provide NULL as argument. Are my assumptions correct? Or did I get something wrong?

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  • Grid view update event form javascript

    - by pranay
    I have grid control select <%--Select--% </ItemTemplate> </asp:TemplateField> </columns> <pagersettings mode="NumericFirstLast" position="Top" pagebuttoncount="5" /> <pagerstyle backcolor="Pink" /> </cc:AppEngineGridView> my code on row create protected override void OnRowCreated(GridViewRowEventArgs e) { try { if (e.Row.RowType == DataControlRowType.DataRow) { e.Row.ID = this.ID + "_" + e.Row.RowIndex; e.Row.Attributes.Add("onmouseover", "this.style.cursor='pointer';this.style.font.weight='bolder';"); e.Row.Attributes.Add("onclick", "DoNav('" + ((LinkButton)e.Row.FindControl("lbtn1")).ClientID + "');"); } } protected void grduser_RowUpdating(object sender, GridViewUpdateEventArgs e) { grdview_RowClickCommand(sender, e); } Javascript : function DoNav(id) { $("#"+id).click(); } Now my question is when i click on the row it do post back but it didnt call rowupdate event How can do this i.e using javascript to call row update command of the grid.

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  • trying to make an accordion menu from a list - jquery indexhibit

    - by orionrush
    Hello - Im teaching my self javascript & jquery so this might be a bit of a low brow question or entirely too much code for anyone to wade through, but Im hoping for some feedback. I have looked around and haven't found a thread that looks like it will deals neatly with my question. Im using the cms indexhibit (cant create a new tag!) and trying to create an accordion style menu from the menu list it generates. I basically have the behaviour Im after, modifying an existing bit of work but there are quite a few foibles, which are no doubt a conflict between the .click and .toggle and a confused use if statements. I basically want to start from scratch and redo this so I can a) learn from my mistakes b) understand what's happening. Im having trouble now because I dont know where to go from here, or how to trouble shoot it. Can anyone give me a quick analysis how the the script in the head of the document work together? Also any insight into the nature of the conflicts Im seeing and what approach might take to remedy them? If you were going to start afresh what would be your approach? Here is a test to see it in action (warts and all): http://stillstatic.nfshost.com/ This script goes into the document head: <script type='text/javascript'> //im not entirely clear as to what this achieves path = 'path/to/script/'; $(document).ready(function() { setTimeout('move_up()', 1); expandingMenu(0); expandingMenu(1); expandingMenu(2); expandingMenu(3); expandingMenu(4); //etc }); </script> the generated list: <ul> <li class='section-title active_menu'>blogs</li> <li><a class="active" href='#' onclick="do_click();">3</a></li> </ul> <ul> //this menu section dose not have a label: class .section-title <li><a href='#' onclick="do_click();">1</a></li> <li><a href='#' onclick="do_click();">2</a></li> </ul> <ul> //this menu section is not the 'active menu' this is achieved by the jquery script <li class='section-title'>writing</li> <li><a href='#' onclick="do_click();">4</a></li> <li><a href='#' onclick="do_click();">5</a></li> </ul> The meat of in an external script: function expandingMenu(num) { var speed = 500; var menu_title = $("#menu ul").eq(num).children(":first"); // ie. first child be the title with the class .section-title unless the user turned it off var menu_items = $("#menu ul").eq(num).children().filter(function (index) { return index 0; }); // ie. any li NOT in position 0, below li.section-title if (menu_items.is(".active") == true) { menu_title.addClass("active_menu"); //Add a class to the active list so we can style it. } if (menu_title.is(".section-title") == true){ // this if prevents interference with users who turn off the section titling if ((menu_items.is(".active") == false) && (menu_items.is(":visible")) ) { menu_items.hide(0);// first we hide the inactive exhibits } $('li').click(function (){ if ( (menu_title.is(":visible") == true) ){ menu_items.hide(speed); } if ( (menu_items.is(":hidden") == true ) && (('')) ){// ?! without this second condition things break down. . . menu_items.show(speed); } }) menu_title.css({cursor:"pointer"}).toggle( // add click functions + pointer to menu_title function () { menu_items.show(speed);//Open it up }, function () { // this function could even be empty but without the if things get weird if (menu_items.is(".xx")) menu_items.hide(speed); //Take the menu item off of active duty! } ) } }

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  • Why doesn't Perl threading work when I call readdir beforehand?

    - by Kevin
    Whenever I call readdir before I create a thread, I get an error that looks like this: perl(2820,0x7fff70c33ca0) malloc: * error for object 0x10082e600: pointer being freed was not allocated * set a breakpoint in malloc_error_break to debug Abort trap What's strange is that it happens when I call readdir before I create a thread (i.e. readdir is not called in any concurrent code). I don't even use the results from readdir, just making the call to it seems to screw things up. When I get rid of it, things seem to work fine. Some example code is below: opendir(DIR, $someDir); my @allFiles = readdir(DIR); close(DIR); my $thread = threads-create(\&sub1); $thread-join(); sub sub1 { print "in thread\n" }

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  • jQuery .submit() woes with IE8

    - by Jitesh
    I am trying to submit a delete link click via a http post to my asp.net mvc controller. While my code below works for chrome it does not work in IE8. Any pointer will be very useful. Setup:- Browser: IE8 jQuery: 1.4.1 MVC: 2.0 The delete link is:- <a title="Delete contact" href="/Contacts/Delete/<%= Model.Contact.Id %>" class="delete" rel="Are you sure you want to delete <%= Html.Encode(Model.Contact.Name) %>?">Delete</a> and the jqeury handler for the click of delete is $("a.delete").click(function() { if (confirm($(this).attr("rel"))) { var form = "<form method='POST' action='" + $(this).attr("href") + '" style='display:none;'></form>"; $(form).submit(); } return false; });

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  • How do I split up a long value (32 bits) into four char variables (8bits) using C?

    - by Jordan S
    I have a 32 bit long variable, CurrentPosition, that I want to split up into 4, 8bit characters. How would I do that most efficiently in C? I am working with an 8bit MCU, 8051 architectecture. unsigned long CurrentPosition = 7654321; unsigned char CP1 = 0; unsigned char CP2 = 0; unsigned char CP3 = 0; unsigned char CP4 = 0; // What do I do next? Should I just reference the starting address of CurrentPosition with a pointer and then add 8 two that address four times? It is little Endian. ALSO I want CurrentPosition to remain unchanged.

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  • Making a video with opencv and ffmpeg. How to find the right color format?

    - by luc
    I have a webcam video recorder program built with python, opencv and ffmpeg It works ok except that the color of the video is more blue than the reality. The problem seems to come from color format of images. It seems that OpenCv is giving BGR images and ffmpeg+libx264 is expecting YUV420p. I've read that YUV420p correspond to YCbCr. opencv has no conversion from BGR to YCbCr. It only has a conversion to YCrCb. I have made some searchs and tried different alternatives to try converting opencv image to something that could be ok for ffmpeg+libx264. None is working. At this point, I am a bit lost and I would appreciate any pointer that could help me to fix this color issue.

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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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  • jQuery click event not working when mouse moves from one div to another with button held down

    - by Acorn
    I've made a page that uses jQuery to allow you to place <div>s on the page based on your mouse coordinates when you click. The page And here's the javascript: $('document').ready(function() { $("#canvas").click(function(e){ var x = e.pageX - this.offsetLeft; var y = e.pageY - this.offsetTop; $(document.createElement('div')).css({'left':x + 'px', 'top':y + 'px'}).addClass('tile').appendTo('#canvas'); }); }); I've found that if you mousedown in the div#canvas and mouseup with your pointer over a placed <div> (or vice versa) then a new <div> doesn't get placed. Why is this?

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  • Which tool can list writing access to a specific variable in C?

    - by Lichtblitz
    Unfortunately I'm not even sure how this sort of static analysis is called. It's not really control flow analysis because I'm not looking for function calls and I don't really need data flow analysis because I don't care about the actual values. I just need a tool that lists the locations (file, function) where writing access to a specific variable takes place. I don't even care if that list contained lines that are unreachable. I could imagine that writing a simple parser could suffice for this task but I'm certain that there must be a tool out there that does this simple analysis. As a poor student I would appreciate free or better yet open source tools and if someone could tell me how this type of static analysis is actually called, I would be equally grateful! EDIT: I forgot to mention there's no pointer arithmetic in the code base.

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  • not able to select hidden link - selenium

    - by Maddy
    I have to select web link when i mouse hover to particular frame in the webpage, the button(link to next page) will be visible. WebElement mainElement = driver.findElement(By.xpath(<frame xpath >)); Actions builder = new Actions(driver); builder.moveToElement(mainElement); WebElement button1 = driver.findElement(By.xpath("//*[@id='currentSkills']/div[1]/div/a")); builder.moveToElement(button1).click().perform(); I am still unable to select the particular link when i execute, the following error am getting org.openqa.selenium.ElementNotVisibleException: Element is not currently visible and so may not be interacted with (WARNING: The server did not provide any stacktrace information) Command duration or timeout: 131 milliseconds But when i hover mouse pointer to the particular frame during AUT(just to move to particular frame without clicking anything), then test is executing sucessfully. I know this can be handled by JS. But i want to find out is there any solution within selenium webdriver Your help is much appreciated... Thanks Madan

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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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