Search Results

Search found 18464 results on 739 pages for 'virtual functions'.

Page 541/739 | < Previous Page | 537 538 539 540 541 542 543 544 545 546 547 548  | Next Page >

  • Does C++ require a destructor call for each placement new?

    - by Josh Haberman
    I understand that placement new calls are usually matched with explicit calls to the destructor. My question is: if I have no need for a destructor (no code to put there, and no member variables that have destructors) can I safely skip the explicit destructor call? Here is my use case: I want to write C++ bindings for a C API. In the C API many objects are accessible only by pointer. Instead of creating a wrapper object that contains a single pointer (which is wasteful and semantically confusing). I want to use placement new to construct an object at the address of the C object. The C++ object will do nothing in its constructor or destructor, and its methods will do nothing but delegate to the C methods. The C++ object will contain no virtual methods. I have two parts to this question. Is there any reason why this idea will not work in practice on any production compiler? Does this technically violate the C++ language spec?

    Read the article

  • Return from parent sub in Perl

    - by JS Bangs
    I want to write a subroutine which causes the caller to return under certain conditions. This is meant to be used as a shortcut for validating input to a function. What I have so far is: sub needs($$) { my ($condition, $message) = @_; if (not $condition) { print "$message\n"; # would like to return from the *parent* here } return $condition; } sub run_find { my $arg = shift @_; needs $arg, "arg required" or return; needs exists $lang{$arg}, "No such language: $arg" or return; # etc. } The advantage of returning from the caller in needs would then be to avoid having to write the repetitive or return inside run_find and similar functions.

    Read the article

  • portable way to deal with 64/32 bit time_t

    - by MK
    I have some code which is built both on Windows and Linux. Linux at this point is always 32bit but Windows is 32 and 64bit. Windows wants to have time_t be 64 bit and Linux still has it as 32 bit. I'm fine with that, except in some places time_t values are converted to strings. So when time_T is 32 bit it should be done with %d and when it is 64bit with %lld... what is the smart way to do this? Also: any ideas how I may find all places where time_t's are passed to printf-style functions to address this issue?

    Read the article

  • Can I run multiple websites under a single membership database?

    - by higgsy
    Hi all, I'm trying to plan a series of websites that all share many of the resources such as css/jscript/images/content etc. For this reason I wanted to run all of the websites under the same application and IIS profile, but depending on the URL being used change the masterpage and theme/skin. The ASP.NET membership database seems as if it was designed with this goal in mind because it allows you to setup multiple applications, however I believe the purpose for which this was built was to allow applications to be run under virtual directories/fodlers, not on seperate urls. Is it possible to map a url to a particular application? Thanks in advance Al

    Read the article

  • Could someone explain __declspec(naked) please?

    - by Scott
    I'm looking into porting a script engine written for Windows to Linux; it's for Winamp's visualization platform AVS. I'm not sure if it's even possible at the moment. From what I can tell the code is taking the addresses of the C functions nseel_asm_atan and nseel_asm_atan_end and storing them inside a table that it can reference during code execution. I've looked at MS's documentation, but I'm unsure what __declspec(naked) really does. What is prolog and epilog code mentioned in the documentation? Is that related to Windows calling conventions? Is this portable? Know of any Linux-based examples using similar techniques? static double (*__atan)(double) = &atan; __declspec ( naked ) void nseel_asm_atan(void) { FUNC1_ENTER *__nextBlock = __atan(*parm_a); FUNC_LEAVE } __declspec ( naked ) void nseel_asm_atan_end(void) {}

    Read the article

  • How to OrderBy on a generic IEnumerable (IEnumerable<T>) using LINQ in C#?

    - by Jeffrey
    In my generic repository I have below method: public virtual IEnumerable<T> GetAll<T>() where T : class { using (var ctx = new DataContext()) { ctx.ObjectTrackingEnabled = false; var table = ctx.GetTable<T>().ToList().AsReadOnly(); return table; } } T is a Linq to Sql class and I want to be able to OrderBy on a particular property. Say if T has property name "SortOrder" then do OrderBy on this property. But I am not sure how I can achieve this. So I need some helps. Thank you!

    Read the article

  • Updating variables in XSL

    - by Stroboskop
    Is there any way in XSL to update a global variable? I want to check what elements i already transformed and act accordingly. That would require me to somehow add the names of the elements to some sort of list and update it each time a new element is transformed. But since xsl:variable isn't "variable" in the sense one would expect, i have no way of adding anything to it once it has been defined. I have multiple included data files, so using xsl functions that only know the current set of nodes will not help.

    Read the article

  • CLR - Common language runtime detected an invalid program in VS.NET

    - by Jimmy
    I have been using Visual Studio 2008 quite long but lately I am getting this message when I am developing an application in C#: Common language runtime detected an invalid program This happens when I try to enter to the properties of a component (text masked box properties, tool box property etc..). But it really became a problem when I tried to launch an other solution that I downloaded from the Developer's 5 star program of Microsoft and it didn't allowed me to launch at all and just got the same problem... I looked for the answer at google but just got some clues about people having the same vague error but in different situations like in ASP.NET I would appreciate any help with this issue... :( I do not want to reinstall VS, that will be my last resource... Update: I never figured out what the problem was so I installed a virtual machine with Windows XP on it, there I only have Visual Studio and Netbeans.

    Read the article

  • What is the difference between an object's scope and it's context in javascript?

    - by DKinzer
    In the vernacular, scope and context have a lot in common. Which is why I get confused when I read references to both, such as in the quote below from an article on closures: Scope refers to where variables and functions are accessible, and in what context it is being executed. (@robertnyman) As far as I can tell, context is just a reference to an object. Can someone please explain what exactly is context, as used, for instance, in the jQuery syntax, $(selector, context). And is an object's scope the same at it's context?

    Read the article

  • Getting the last element of a Postgres array, declaratively

    - by Wojciech Kaczmarek
    How to obtain the last element of the array in Postgres? I need to do it declaratively as I want to use it as a ORDER BY criteria. I wouldn't want to create a special PGSQL function for it, the less changes to the database the better in this case. In fact, what I want to do is to sort by the last word of a specific column containing multiple words. Changing the model is not an option here. In other words, I want to push Ruby's sort_by {|x| x.split[-1]} into the database level. I can split a value into array of words with Postgres string_to_array or regexp_split_to_array functions, then how to get its last element?

    Read the article

  • strtok program crashing.

    - by baskin
    Hi, the program for strtok given on http://www.opengroup.org/onlinepubs/000095399/functions/strtok.html crashes everytime.. #include <string.h> ... char *token; char *line = "LINE TO BE SEPARATED"; char *search = " "; /* Token will point to "LINE". */ token = strtok(line, search); /* Token will point to "TO". */ token = strtok(NULL, search); If I use a char array for variable 'line', it works. i.e. char line[] = "LINE TO BE SEPARATED" works. Kindly explain.

    Read the article

  • C++ Vector at/[] operator speed

    - by sub
    In order to give functions the option to modify the vector I can't do curr = myvec.at( i ); doThis( curr ); doThat( curr ); doStuffWith( curr ); But I have to do: doThis( myvec.at( i ) ); doThat( myvec.at( i ) ); doStuffWith( myvec.at( i ) ); (as the answers of my other question pointed out) I'm going to make a hell lot of calls to myvec.at() then. How fast is it, compared to the first example using a variable to store the result? Is there a different option for me? Can I somehow use pointers? When it's getting serious there will be thousands of calls to myvec.at() per second. So every little performance-eater is important.

    Read the article

  • How to list all items in custom taxonomy with a permanlink in Wordpress

    - by Constant M
    Hi, Not sure how to word this. I've set up a type in Wordpress called Products. I also have two taxonomies linked to Products called Brands and Categories. When you create a product you can set to which Brand and Category the product belong to. It works perfectly when using the type as permalink to list everything within a type http://sitename.com/products but I can't seem to get the taxonomies working in the same way, ie. list all the items within a taxonomy (like an archive, I suppose): http://sitename.com/brands http://sitename.com/categories Is this possible, and if so, what could I possibly be doing wrong? I would try and set up some rewrite rules in functions.php, but I don't know what the query string looks like if you want to list items in a taxonomy, and if this is even possible. If it helps, I'm using the plugins More Types and Ultimate Taxonomy Manager to create the types and taxonomies.

    Read the article

  • Compiling C-dll for Python OR SWIG-module creation, how to continue ??

    - by ljuju
    I reference this file "kbdext.c" and its headerfile listed on http://www.docdroppers.org/wiki/index.php?title=Writing_Keyloggers (the listings are at the bottom). I've been trying to compile this into a dll for use in Python or Visual Basic, but have not succeeded. I'm not familiar with C or GCC to sort out the problems or do the dll compile correctly. (I also get an error about snprintf not being declared when doing a regular compile of all the files). What are the steps I should do to make all functions available for other languages and external apps? Or is it perhaps easier to use SWIG and make a python module, instead of compiling a DLL?

    Read the article

  • How to use YT thumb in plugin

    - by Frank Morrison
    I'm using two plugins on my wordpress site: Auto post youtube Pulls a youtube video then drafts it for me. I use this on my index page beside the post code and the thumbnail appears great: <?php tern_wp_youtube_image(); ?> Top Ten Which I use to display the most viewed posts on a page. Not looking great at the moment, but will fix styling later. This is the code to display popular posts: <?php if(function_exists('tptn_show_pop_posts')) tptn_show_pop_posts(); ?> Is it possible for me to use the youtube image in the popular post function? Or is it because they are seperate they cannot work together without a lot of code? Thanks in advance! Some links incase anybody wants to check them out http://wordpress.org/extend/plugins/top-10/ http://www.ternstyle.us/products/plugins/wordpress/wordpress-automatic-youtube-video-posts/wordpress-automatic-youtube-video-posts-functions

    Read the article

  • misleading plot issue in mathematica

    - by Qiang Li
    I want to study some "strange" functions by plotting them out in mathematica. One example is the following: mod2[x_] := Which[Mod[x, 2] >= 1, -2 + Mod[x, 2], True, Mod[x, 2]]; f[x_] := Which[-1 <= x <= 1, Abs[x], True, Abs[mod2[x]]]; fn[x_, n_] := Sum[(3/4)^i*f[4^n*x], {i, 0, n}] Plot[{fn[x, 0], fn[x, 1], fn[x, 2], fn[x, 5]}, {x, -2, 2}] However, the plot I got from mma is misleading, in the sense that the maxima and minima of fn[x, 5] should be on the same two levels. But due to high oscillation of the function, and the fact that clearly mma only takes limited number of points to draw the function, you see the plot exhibit strange behavior. Is there any option in plot to remedy for this? Many thanks.

    Read the article

  • Selenium selected option in dropdown not displayed correctly

    - by luckyfool
    I have the following issue with Selenium Webdriver. There are two dropdown menus on a page i am testing "brand" and "items". The options of "items" depend on which brand you choose. I am trying to iterate through all possible choices and print brand-item pairs. I use two possible ways to pick an option from each dropdown menu Using Select(): def retryingSelectOption(name,n): result=False attempts=0 while attempts<5: try: element=Select(driver.find_element_by_name(name)) element.select_by_index(n) print element.all_selected_options[0].text result=True break except StaleElementReferenceException: pass attempts+=1 return result And using .click(): def retryingClickOption(name,n): result=False attempts=0 while attempts<5: try: driver.find_element_by_name(name).find_elements_by_tag_name("option")[n].click() result=True break except StaleElementReferenceException: pass attempts+=1 return result My problem is that at ,what seem to me as random moments (sometimes it works sometimes it does not), even though the above functions return True and printing out the selected option shows me the correct answer, the browser still displays the previous option. So basically Selenium tells me i have picked the right option but the browser displays the previous one.No idea what is wrong.

    Read the article

  • Profiling help required

    - by Mick
    I have a profiling issue - imagine I have the following code... void main() { well_written_function(); badly_written_function(); } void well_written_function() { for (a small number) { highly_optimised_subroutine(); } } void badly_written_function() { for (a wastefully and unnecessarily large number) { highly_optimised_subroutine(); } } void highly_optimised_subroutine() { // lots of code } If I run this under vtune (or other profilers) it is very hard to spot that anything is wrong. All the hotspots will appear in the section marked "// lots of code" which is already optimised. The badly_written_function() will not be highlighted in any way even though it is the cause of all the trouble. Is there some feature of vtune that will help me find the problem? Is there some sort of mode whereby I can find the time taken by badly_written_function() and all of its sub-functions?

    Read the article

  • matrix = *((fxMatrix*)&d3dMatrix); //Evil?

    - by Xilliah
    I've been using matrix = *((fxMatrix*)&d3dMatrix); for quite a while. It worked fine until my screen turned black and received a bucket of frustration on my desk. fxMatrix contains 4 fxVectors. fxVector used to be 16 bytes, but now it was suddenly 20. This was because it inherited fxStreamable, which added the vTable. So one solution is of course just to not inherit fxStreamable, and leave a comment saying that it must always be 16 bytes and never more. Another solution would be to make conversion functions, and copy the matrix completely. This makes it more secure, but has an impact on the performance. I suppose this is the best idea. Another solution is to not convert at all, and stick to D3DXMATRIX, but this makes the engine inconsistent and I personally really dislike this idea. What is your opinion?

    Read the article

  • MySQL LEFT JOIN, GROUP BY and ORDER BY not working as required

    - by Simon
    I have a table 'products' => ('product_id', 'name', 'description') and a table 'product_price' => ('product_price_id', 'product_id', 'price', 'date_updated') I want to perform a query something like SELECT `p`.*, `pp`.`price` FROM `products` `p` LEFT JOIN `product_price` `pp` ON `pp`.`product_id` = `p`.`product_id` GROUP BY `p`.`product_id` ORDER BY `pp`.`date_updated` DESC As you can probably guess the price changes often and I need to pull out the latest one. The trouble is I cannot work out how to order the LEFT JOINed table. I tried using some of the GROUP BY functions like MAX() but that would only pull out the column not the row. Thanks.

    Read the article

  • C++ Basic Class Layout

    - by Spencer
    Learning C++ and see the class laid out like this: class CRectangle { int x, y; public: void set_values (int,int); int area () {return (x*y);} }; void CRectangle::set_values (int a, int b) { x = a; y = b; } I know Java and methods(functions) in Java are written within the class. The class looks like a Java interface. I know I can write the class like this: class CRectangle { int x, y; public: void set_values (int a, int b) { x = a; y = b; }; int area () {return (x*y);} }; But is there a difference or standard?

    Read the article

  • C++: Switching from MSVC to G++: Global Variables

    - by feed the fire
    I recently switched to Linux and wanted to compile my Visual Studio 2010 C++ source code, which uses only the STL, on G++. My Linux machine currently isn't available but I can try to tell you what is going on, first: As I try to compile my project, all global variables I use in main and which perfectly work on MSVC result in myGlobalVar is not defined in this scope errors. My project is built nearly the same as the example below: // myclass.h class myClass { // .... }; extern myClass globalInstance; // myclass.cpp #include "myclass.h" // myClass functions located here myClass globalInstance; // main.cpp #include "myclass.h" int main( ) { // Accessing globalInstance results in an error: Not defined in this scope } What am I doing wrong? Where are the differences between G++ and MSVC in terms of global variables?

    Read the article

  • JavaScript constructors inside a namespace

    - by Joe
    I have read that creating a namespace for JavaScript projects helps to reduce conflicts with other libraries. I have some code with a lot of different types of objects for which I have defined constructor functions. Is it good practice to put these inside the namespace as well? For example: var shapes = { Rectangle: function(w, h) { this.width = w; this.height = h; } }; which can be called via: var square = new shapes.Rectangle(10,10);

    Read the article

  • Vector of objects

    - by Paul
    I've got a abstract class class A { public: virtual void somefunction() = ; }; and some different classes that inherit this class: class Ab { public: void somefunction(); }; etc. I want to make a vector containing some objects of these classes (how many depends on input parameters) so I can access these easily later. However I'm a bit lost on how to do this. My best idea is vector<A> *objectsVector; Ab AbObject; objectsVector.push_back(AbObject); However this gives me a huge amout of errors from various .h files in /usr/include/c++ How should i solve this?

    Read the article

  • Change a registry value in vb.net

    - by mhofer
    Hello, I have searched a lot to find a solution for my problem, but I can't find any specific solution. I need to change a value which is stored under HKEY_LOCAL_MACHINE\SOFTWARE\APP_NAME. It is not possible to use .NET's registry functions, since they have drastic restrictions. The following snippet should solve my problem: Dim regKey As RegistryKey Dim ver As Decimal regKey = My.Computer.Registry.LocalMachine.OpenSubKey("HKEY_LOCAL_MACHINE\SOFTWARE\APP_NAME", True) regKey.SetValue("IP", "192.168.10.15:18500") regKey.Close() Unfortunately, I get a NullReferenceExeption when I try to set the value. What should I do? I have imported Microsoft.Win32 and RegistryKey doesn't accept any constructor... cheers mike

    Read the article

< Previous Page | 537 538 539 540 541 542 543 544 545 546 547 548  | Next Page >