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  • Overriding vs Virtual

    - by anonymous
    What is the purpose of using the reserved word virtual in front of functions? If I want a child class to override a parent function, I just declare the same function such as "void draw(){}". class Parent{ public: void say(){ std::cout << "1"; }}; class Child : public Parent{public:void say(){ std::cout << "2"; } }; int main() { Child* a = new Child(); a->say(); return 0; } The output is 2. So again, why would the reserved word "virtual" be necessary in the header of say() ? Thanks a bunch.

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  • Why I have to redeclare a virtual function while overriding [C++]

    - by Neeraj
    #include <iostream> using namespace std; class Duck { public: virtual void quack() = 0; }; class BigDuck : public Duck { public: // void quack(); (uncommenting will make it compile) }; void BigDuck::quack(){ cout << "BigDuckDuck::Quack\n"; } int main() { BigDuck b; Duck *d = &b; d->quack(); } Consider this code, the code doesn't compiles. However when I declare the virtual function in the subclass, then it compiles fine. The compiler already has the signature of the function which the subclass will override, then why a redeclaration is required? Any insights.

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  • Apache virtual host does not work properly

    - by Jori
    I have read a lot of information all over the Internet regarding this subject, and can not figure out what I'am doing wrong. I'm trying to host two websites under different names locally under Windows 7 with Apaches Virtual Hosting functionality. This is what I have done already: In the httpd.conf file I uncommented the following line, so that the virtual host configuration file will be included in the main configuration sequence. # Virtual hosts Include conf/extra/httpd-vhosts.conf This is how I edited my httpd-vhosts.conf: # # Virtual Hosts # # If you want to maintain multiple domains/hostnames on your # machine you can setup VirtualHost containers for them. Most configurations # use only name-based virtual hosts so the server doesn't need to worry about # IP addresses. This is indicated by the asterisks in the directives below. # # Please see the documentation at # <URL:http://httpd.apache.org/docs/2.2/vhosts/> # for further details before you try to setup virtual hosts. # # You may use the command line option '-S' to verify your virtual host # configuration. # # Use name-based virtual hosting. # NameVirtualHost *:80 # # VirtualHost example: # Almost any Apache directive may go into a VirtualHost container. # The first VirtualHost section is used for all requests that do not # match a ServerName or ServerAlias in any <VirtualHost> block. # #<VirtualHost *:80> # ServerAdmin [email protected] # DocumentRoot "C:/apache/docs/dummy-host.localhost" # ServerName dummy-host.localhost # ServerAlias www.dummy-host.localhost # ErrorLog "logs/dummy-host.localhost-error.log" # CustomLog "logs/dummy-host.localhost-access.log" common #</VirtualHost> # #<VirtualHost *:80> # ServerAdmin [email protected] # DocumentRoot "C:/apache/docs/dummy-host2.localhost" # ServerName dummy-host2.localhost # ErrorLog "logs/dummy-host2.localhost-error.log" # CustomLog "logs/dummy-host2.localhost-access.log" common #</VirtualHost> <VirtualHost *:80> ServerName arterieur DocumentRoot "J:/webcontent/www20" <Directory "J:/webcontent/www20"> Order allow,deny Allow from all </Directory> </VirtualHost> As you can see I commented the Virtual Host examples out and added my own one (I did one for this example). Also am I sure that J:\webcontent\www20 exists. At last I edited the Windows host file located in: C:\Windows\System32\drivers\etc\hosts, now it looks this: # Copyright (c) 1993-2009 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # 102.54.94.97 rhino.acme.com # source server # 38.25.63.10 x.acme.com # x client host # localhost name resolution is handled within DNS itself. # 127.0.0.1 localhost # ::1 localhost 127.0.0.1 arterieur Then I restarted Apache with the Apache Service Monitor, and it gave me the following fatal error: The requested operation has failed!, I tried to look at the apache/logs/error.log file but I did not log anything, I guess it only logs the errors after startup. Does anyone knows what I'am doing wrong?

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  • Problems Allocating Objects of Derived Class Where Base Class has Abstract Virtual Functions

    - by user1743901
    I am trying to get this Zombie/Human agent based simulation running, but I am having problems with these derived classes (Human and Zombie) who have parent class "Creature". I have 3 virtual functions declared in "Creature" and all three of these are re-declared AND DEFINED in both "Human" and "Zombie". But for some reason when I have my program call "new" to allocate memory for objects of type Human or Zombie, it complains about the virtual functions being abstract. Here's the code: definitions.h #ifndef definitions_h #define definitions_h class Creature; class Item; class Coords; class Grid { public: Creature*** cboard; Item*** iboard; int WIDTH; int HEIGHT; Grid(int WIDTHVALUE, int HEIGHTVALUE); void FillGrid(); //initializes grid object with humans and zombies void Refresh(); //calls Creature::Die(),Move(),Attack(),Breed() on every square void UpdateBuffer(char** buffer); bool isEmpty(int startx, int starty, int dir); char CreatureType(int xcoord, int ycoord); char CreatureType(int startx, int starty, int dir); }; class Random { public: int* rptr; void Print(); Random(int MIN, int MAX, int LEN); ~Random(); private: bool alreadyused(int checkthis, int len, int* rptr); bool isClean(); int len; }; class Coords { public: int x; int y; int MaxX; int MaxY; Coords() {x=0; y=0; MaxX=0; MaxY=0;} Coords(int X, int Y, int WIDTH, int HEIGHT) {x=X; y=Y; MaxX=WIDTH; MaxY=HEIGHT; } void MoveRight(); void MoveLeft(); void MoveUp(); void MoveDown(); void MoveUpRight(); void MoveUpLeft(); void MoveDownRight(); void MoveDownLeft(); void MoveDir(int dir); void setx(int X) {x=X;} void sety(int Y) {y=Y;} }; class Creature { public: bool alive; Coords Location; char displayletter; Creature() {Location.x=0; Location.y=0;} Creature(int i, int j) {Location.setx(i); Location.sety(j);} virtual void Attack() =0; virtual void AttackCreature(Grid G, int attackdirection) =0; virtual void Breed() =0; void Die(); void Move(Grid G); int DecideSquare(Grid G); void MoveTo(Grid G, int dir); }; class Human : public Creature { public: bool armed; //if armed, chances of winning fight increased for next fight bool vaccinated; //if vaccinated, no chance of getting infected int bitecount; //if a human is bitten, bite count is set to a random number int breedcount; //if a human goes x steps without combat, will breed if next to a human int starvecount; //if a human does not eat in x steps, will die Human() {displayletter='H';} Human(int i, int j) {displayletter='H';} void Attack(Grid G); void AttackCreature(Grid G, int attackdirection); void Breed(Grid G); //will breed after x steps and next to human int DecideAttack(Grid G); }; class Zombie : public Creature { public: Zombie() {displayletter='Z';} Zombie(int i, int j) {displayletter='Z';} void Attack(Grid G); void AttackCreature(Grid G, int attackdirection); void Breed() {} //does nothing int DecideAttack(Grid G); void AttackCreature(Grid G, int attackdirection); }; class Item { }; #endif definitions.cpp #include <cstdlib> #include "definitions.h" Random::Random(int MIN, int MAX, int LEN) //constructor { len=LEN; rptr=new int[LEN]; //allocate array of given length for (int i=0; i<LEN; i++) { int random; do { random = rand() % (MAX-MIN+1) + MIN; } while (alreadyused(random,LEN,rptr)); rptr[i]=random; } } bool Random::alreadyused(int checkthis, int len, int* rptr) { for (int i=0; i<len; i++) { if (rptr[i]==checkthis) return 1; } return 0; } Random::~Random() { delete rptr; } Grid::Grid(int WIDTHVALUE, int HEIGHTVALUE) { WIDTH = WIDTHVALUE; HEIGHT = HEIGHTVALUE; //builds 2d array of creature pointers cboard = new Creature**[WIDTH]; for(int i=0; i<WIDTH; i++) { cboard[i] = new Creature*[HEIGHT]; } //builds 2d array of item pointers iboard = new Item**[WIDTH]; for (int i=0; i<WIDTH; i++) { iboard[i] = new Item*[HEIGHT]; } } void Grid::FillGrid() { /* For each creature pointer in grid, randomly selects whether to initalize as zombie, human, or empty square. This methodology can be changed to initialize different creature types with different probabilities */ int random; for (int i=0; i<WIDTH; i++) { for (int j=0; j<HEIGHT; j++) { Random X(1,100,1); //create a single random integer from [1,100] at X.rptr random=*(X.rptr); if (random < 20) cboard[i][j] = new Human(i,j); else if (random < 40) cboard[i][j] = new Zombie(i,j); else cboard[i][j] = NULL; } } //at this point every creature pointer should be pointing to either //a zombie, human, or NULL with varying probabilities } void Grid::UpdateBuffer(char** buffer) { for (int i=0; i<WIDTH; i++) { for (int j=0; j<HEIGHT; j++) { if (cboard[i][j]) buffer[i][j]=cboard[i][j]->displayletter; else buffer[i][j]=' '; } } } bool Grid::isEmpty(int startx, int starty, int dir) { Coords StartLocation(startx,starty,WIDTH,HEIGHT); switch(dir) { case 1: StartLocation.MoveUp(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 2: StartLocation.MoveUpRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 3: StartLocation.MoveRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 4: StartLocation.MoveDownRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 5: StartLocation.MoveDown(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 6: StartLocation.MoveDownLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 7: StartLocation.MoveLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 8: StartLocation.MoveUpLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; } return 1; } char Grid::CreatureType(int xcoord, int ycoord) { if (cboard[xcoord][ycoord]) //if there is a creature at location xcoord,ycoord return (cboard[xcoord][ycoord]->displayletter); else //if pointer at location xcoord,ycoord is null, return null char return '\0'; } char Grid::CreatureType(int startx, int starty, int dir) { Coords StartLocation(startx,starty,WIDTH,HEIGHT); switch(dir) { case 1: StartLocation.MoveUp(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 2: StartLocation.MoveUpRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 3: StartLocation.MoveRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 4: StartLocation.MoveDownRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 5: StartLocation.MoveDown(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 6: StartLocation.MoveDownLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 7: StartLocation.MoveLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 8: StartLocation.MoveUpLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); } //if function hasn't returned by now, square being looked at is pointer to null return '\0'; //return null char } void Coords::MoveRight() {(x==MaxX)? (x=0):(x++);} void Coords::MoveLeft() {(x==0)? (x=MaxX):(x--);} void Coords::MoveUp() {(y==0)? (y=MaxY):(y--);} void Coords::MoveDown() {(y==MaxY)? (y=0):(y++);} void Coords::MoveUpRight() {MoveUp(); MoveRight();} void Coords::MoveUpLeft() {MoveUp(); MoveLeft();} void Coords::MoveDownRight() {MoveDown(); MoveRight();} void Coords::MoveDownLeft() {MoveDown(); MoveLeft();} void Coords::MoveDir(int dir) { switch(dir) { case 1: MoveUp(); break; case 2: MoveUpRight(); break; case 3: MoveRight(); break; case 4: MoveDownRight(); break; case 5: MoveDown(); break; case 6: MoveDownLeft(); break; case 7: MoveLeft(); break; case 8: MoveUpLeft(); break; case 0: break; } } void Creature::Move(Grid G) { int movedir=DecideSquare(G); MoveTo(G,movedir); } int Creature::DecideSquare(Grid G) { Random X(1,8,8); //X.rptr now points to 8 unique random integers from [1,8] for (int i=0; i<8; i++) { int dir=X.rptr[i]; if (G.isEmpty(Location.x,Location.y,dir)) return dir; } return 0; } void Creature::MoveTo(Grid G, int dir) { Coords OldLocation=Location; Location.MoveDir(dir); G.cboard[Location.x][Location.y]=this; //point new location to this creature G.cboard[OldLocation.x][OldLocation.y]=NULL; //point old location to NULL } void Creature::Die() { if (!alive) { delete this; this=NULL; } } void Human::Breed(Grid G) { if (!breedcount) { Coords BreedLocation=Location; Random X(1,8,8); for (int i=0; i<8; i++) { BreedLocation.MoveDir(X.rptr[i]); if (!G.cboard[BreedLocation.x][BreedLocation.y]) { G.cboard[BreedLocation.x][BreedLocation.y])=new Human(BreedLocation.x,BreedLocation.y); return; } } } } int Human::DecideAttack(Grid G) { Coords AttackLocation=Location; Random X(1,8,8); int attackdir; for (int i=0; i<8; i++) { attackdir=X.rptr[i]; switch(G.CreatureType(Location.x,Location.y,attackdir)) { case 'H': break; case 'Z': return attackdir; case '\0': break; default: break; } } return 0; //no zombies! } int AttackRoll(int para1, int para2) { //outcome 1: Zombie wins, human dies //outcome 2: Human wins, zombie dies //outcome 3: Human wins, zombie dies, but human is bitten Random X(1,100,1); int roll= *(X.rptr); if (roll < para1) return 1; else if (roll < para2) return 2; else return 3; } void Human::AttackCreature(Grid G, int attackdirection) { Coords AttackLocation=Location; AttackLocation.MoveDir(attackdirection); int para1=33; int para2=33; if (vaccinated) para2=101; //makes attackroll > para 2 impossible, never gets infected if (armed) para1-=16; //reduces chance of zombie winning fight int roll=AttackRoll(para1,para2); //outcome 1: Zombie wins, human dies //outcome 2: Human wins, zombie dies //outcome 3: Human wins, zombie dies, but human is bitten switch(roll) { case 1: alive=0; //human (this) dies return; case 2: G.cboard[AttackLocation.x][AttackLocation.y]->alive=0; return; //zombie dies case 3: G.cboard[AttackLocation.x][AttackLocation.y]->alive=0; //zombie dies Random X(3,7,1); //human is bitten bitecount=*(X.rptr); return; } } int Zombie::DecideAttack(Grid G) { Coords AttackLocation=Location; Random X(1,8,8); int attackdir; for (int i=0; i<8; i++) { attackdir=X.rptr[i]; switch(G.CreatureType(Location.x,Location.y,attackdir)) { case 'H': return attackdir; case 'Z': break; case '\0': break; default: break; } } return 0; //no zombies! } void Zombie::AttackCreature(Grid G, int attackdirection) { int reversedirection; if (attackdirection < 9 && attackdirection>0) { (attackdirection<5)? (reversedirection=attackdirection+4):(reversedirection=attackdirection-4); } else reversedirection=0; //this should never happen //when a zombie attacks a human, the Human::AttackZombie() function is called //in the "reverse" direction, utilizing that function that has already been written Coords ZombieLocation=Location; Coords HumanLocation=Location; HumanLocation.MoveDir(attackdirection); if (G.cboard[HumanLocation.x][HumanLocation.y]) //if there is a human there, which there should be G.cboard[HumanLocation.x][HumanLocation.y]->AttackCreature(G,reversedirection); } void Zombie::Attack(Grid G) { int attackdirection=DecideAttack(G); AttackCreature(G,attackdirection); } main.cpp #include <cstdlib> #include <iostream> #include "definitions.h" using namespace std; int main(int argc, char *argv[]) { Grid G(500,500); system("PAUSE"); return EXIT_SUCCESS; }

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  • I&rsquo;m going to have to stop using MS Virtual PC 2007

    - by John Breakwell
    Originally posted on: http://geekswithblogs.net/Plumbersmate/archive/2013/10/23/irsquom-going-to-have-to-stop-using-ms-virtual-pc.aspxFor many years now I’ve been happily chucking around Windows XP virtual hard disks and loading them with Virtual PC. Sadly I’m going to have to turn to something modern as the virtual processor is no longer up to scratch, as I found when trying to install Windows 8.1 evaluation. In the past this would have been a Blue Screen but they’re handled differently in Windows 8, usually with a frowning emoticon. 0x0000005D means UNSUPPORTED_PROCESSOR and the solution would be to enable No-Execute Memory Protection in the BIOS. Virtual PC is ancient so the AMI BIOS has no such setting on any of the menus. Off now to find a virtualisation product I like.

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  • How to Install KVM and Create Virtual Machines on Ubuntu

    - by Chris Hoffman
    If you’re using Linux, you don’t need VirtualBox or VMware to create virtual machines. You can use KVM – the kernel-based virtual machine – to run both Windows and Linux in virtual machines. You can use KVM directly or with other command-line tools, but the graphical Virtual Machine Manager (Virt-Manager) application will feel most familiar to people that have used other virtual machine programs. How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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  • The HTG Guide To Speeding Up Your Virtual Machines

    - by Chris Hoffman
    Virtual machines are demanding beasts, providing virtual hardware and running multiple operating systems on your computer at once. Upgrading your hardware (particularly your RAM and CPU) will always help speed up virtual machines, but there’s more you can do. These tips will help you squeeze every last drop of performance out of your virtual machine, whether you’re using VirtualBox, VMware, Parallels, or any other virtual machine program. How To Create a Customized Windows 7 Installation Disc With Integrated Updates How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using?

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  • Powerpoint not drawing in slide properly...

    - by commradepolski
    So got another issue to post about. I have a user here who uses powerpoint a lot, Office 07 with SP2. When he opens up the presentation, powerpoint opens fine without errors, but does not draw in the main slide properly. So to better explain that, the list on the left hand side, that shows the slides and what order they are in, loads up fine. You can see the slides and the content etc. When you click on a slide, to edit it, it does not draw in on the editing screen. Not really sure how to explain that. The screen where the work on the slide is done, is what is affected. This is a screen shot from my pc not the users. So instead of the screen saying "Click to add title" it would be improperly drawn such that if I were to drag an explorer window across it, it would leave a trail. I have tried reinstalling office, updating it, as well as giving the user a new windows image and nothing has helped. Any help or advice is appreciated.

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  • Create a virtual serial port for widcomm stack under 32feet

    - by i13m
    Hi, all Currently I am doing a project involves a bluetooth communication setup between a PDA and a small embedded device. This small embedded device can only be communicated with a virtual serial port over a bluetooth link. The PDA is the ipaq running with windows mobile 6, and I am using c#. I had done a program which can communication with the serial port over bluetooth. But the only issue is every time I run this program, I have to active the bluetooth radio, and manually pairing this device with the pda via the bluetooth manager. What I want to do is when running this program, it can establish the bluetooth connection between the pda and the embedded module. So I am using functions from the 32feet prject. This is one issue is I cant make the virutal serial port part, as I think the 32feet project can only make virual serial ports for the window bluetooth stack but not the widcomm bluetooth stact, which the ipaq is using. Therefore, are there any existing c# classes or stacks that can make virtual serial port under widcomm for windows mobile 6. Thanks

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  • Doing coding in Linux through a virtual machine on Windows VS partitioning

    - by ihaveitnow
    I already have experience with setting up virtual machines, running them and other minor tasks. Im a gamer, so I wont get rid of windows (for now at least...) but I do want to be a great programmer and to be involved with the Open-Source community. Id like to know if its a good idea to do my programming in linux through a virtual machine, vs giving it a partitioned section of the HDD. Id like to know about performance pros and cons and functionality. All responses are appreciated, thanks in advance. The type of programming I intend to dive into : Android Dev, Web Dev, Desktop Dev...More Android and Web right now though. So im looking at C#,C,C++,Java,PHP,HTML,MySQL...Off the top of the dome. I do web designing as well, so dreamweaver is added as an "essential". But im sure I can do dreamweaver files and upload them to the server after programming in Linux...Right? And any info on IDE's in Linux for the above mentioned are appreciated, but i would prefer going the coding route and understanding the essence of whats happening "under the covers" Thanks to all for reading, I appreciate it. Hope this isnt confusing :S

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  • Has anyone setup tomcat to run virtual hosts using mod_jk

    - by Adam
    I work in OSX primarily with mostly PHP. Normally I work locally using MAMP and virtual hosts setup in my httpd.conf so that I can point a browser to http://some-project and have as many projects as I need setup. We have a project coming up where we need to serve JSP pages and I would like to set up my local apache server to serve only JSP files to Tomcat and everything else to MAMP using the same virtual hosts setup in: ~/applications/MAMP/conf/apache/httpd.conf So far I have: Successfully installed Tomcat Placed mod_jd.so in ~/applications/MAMP/Library/modules/mod_jk.so Added the module by placing: LoadModule jk_module modules/mod_jk.so in ~/applications/MAMP/conf/apache/httpd.conf Created /Library/Tomcat/Home/conf/jk/workers.properties and added the following lines: workers.tomcat_home=/Library/Tomcat workers.java_home=/System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Home ps=/ worker.list=ajp12, ajp13 worker.ajp13.port=8009 worker.ajp13.host=localhost worker.ajp12.type=ajp13 worker.ajp13.mount=/*.jsp added the following lines: JkWorkersFile /Library/Tomcat/Home/conf/workers.properties JkLogFile /Library/Tomcat/Home/logs/mod_jk.log JkLogLevel debug to ~/applications/MAMP/conf/apache/httpd.conf I cannot start my MAMP however when these last two lines are present in my httpd.conf. Does anyone work like this? Any tips? Any clear ideas of what I'm doing wrong?

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  • How to control virtual memory management in linux?

    - by chmike
    I'm writing a program that uses an mmap file to hold a huge buffer organized as an array of 64 MB blocks. The blocks are used to aggregate data received from different hosts through the network. As a consequence the total data size written in each block is not known in advance. Most of the time it is only 2MB but in some cases it can be up to 20MB or more. The data doesn't stay long in the buffer. 90% is deleted after less than a second and the rest is transmitted to another host. I would like to know if there is a way to tell the virtual memory manager that ram pages are not dirty anymore when data is deleted. Should I use mmap and munmap when a block is used and released to control the virtual memory ? What would be the overhead of doing this ? Also, some colleagues expressed concerns about the performance impact of allocating such a big mmap space. I expect it to behave like a swap file so that only dirty pages are to be considered.

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  • C++ Virtual Methods for Class-Specific Attributes or External Structure

    - by acanaday
    I have a set of classes which are all derived from a common base class. I want to use these classes polymorphically. The interface defines a set of getter methods whose return values are constant across a given derived class, but vary from one derived class to another. e.g.: enum AVal { A_VAL_ONE, A_VAL_TWO, A_VAL_THREE }; enum BVal { B_VAL_ONE, B_VAL_TWO, B_VAL_THREE }; class Base { //... virtual AVal getAVal() const = 0; virtual BVal getBVal() const = 0; //... }; class One : public Base { //... AVal getAVal() const { return A_VAL_ONE }; BVal getBVal() const { return B_VAL_ONE }; //... }; class Two : public Base { //... AVal getAVal() const { return A_VAL_TWO }; BVal getBVal() const { return B_VAL_TWO }; //... }; etc. Is this a common way of doing things? If performance is an important consideration, would I be better off pulling the attributes out into an external structure, e.g.: struct Vals { AVal a_val; VBal b_val; }; storing a Vals* in each instance, and rewriting Base as follows? class Base { //... public: AVal getAVal() const { return _vals->a_val; }; BVal getBVal() const { return _vals->b_val; }; //... private: Vals* _vals; }; Is the extra dereference essentially the same as the vtable lookup? What is the established idiom for this type of situation? Are both of these solutions dumb? Any insights are greatly appreciated

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  • Images not shown when publishing MVC application to virtual directory inside default web-site

    - by Michael Sagalovich
    Hi! I am developing an application using ASP.NET MVC 1 and VS2008. When I deploy it to the default web-site in my IIS6 on WinXP, all images are shown correctly, path to any given image is localhost/Content/ImagesUI/[image].[ext] When I deploy it to the virtual directory, created inside the same site, any image request returns IIS standard 404 error page, while the path is localhost/[DirectoryName]/Content/ImagesUI/[image].[ext] - that seems to be correct, true? I am mapping .* to c:\windows\microsoft.net\framework\v2.0.50727\aspnet_isapi.dll in both site and directory configurations. When this mapping is removed, images are shown correctly. However, all other URLs do not work, of course. When I am trying to open an image in browser using the URL to it, aspnet_wp.exe process is not even started (I restarted IIS to test it) - I merely get 404 or the image, depending on the presence of * mapping. Thus, I suppose it has nothing to do neither with routes registered for MVC, nor with ASP. The solution that I found is to make Content folder a virtual directory and remove * mapping from its configuration. While that's OK to some extent, I want a better solution, which will explain and eliminate the cause of the problem, not just workaround it. Thanks for your help!

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  • Remote Desktop to Your Azure Virtual Machine

    - by Shaun
    The Windows Azure Team had just published their new development portal this week and the SDK 1.3. Within this new release there are a lot of cool feature available. The one I’m looking forward to is Remote Desktop Access to your running Windows Azure Virtual Machine.   Configuration Remote Desktop Access It would be very simple to make the azure service enable the remote desktop access. First of all let’s create a new windows azure project from the Visual Studio. In this example I just created a normal MVC 2 web role without any modifications. Then we right-click the azure project node in the solution explorer window and select “Publish”. Then let’s select the “Deploy your Windows Azure project to Windows Azure” on the top radio button. And then select the credential, deployment service/slot, storage and label as susal. You must have the Management API Certificates uploaded to your Windows Azure account, and install the certification on you machine before in order to use this one-click deployment feature. If you are familiar with this dialog you will notice that there’s a linkage named “Configure Remote Desktop connections”. Here is where you need to make this service enable the remote desktop feature. After clicked this link we will set the configuration of the remote desktop access authorization information. There are 4 steps we need to do to configure our access. Certificates: We need either create or select a certificate file in order to encypt the access cerdenticals. In this example I will use the certificate file for my Management API. Username: The remote desktop user name to access the virtual machine. Password: The password for the access. Expiration: The access cerdentals would be expired after 1 month by default but we can amend here. After that we clicked the OK button to back to the publish dialog.   The next step is to back to the new windows azure portal and navigate to the hosted services list. I created a new hosted service and upload the certificate file onto this service. The user name and password access to the azure machine must be encrypted from the local machine, and then send to the windows azure platform, then decrypted on the azure side by the same file. This is why we need to upload the certificate file onto azure. We navigated to the “Hosted Services, Storage Accounts & CDN"” from the left panel and created a new hosted service named “SDK13” and selected the “Certificates” node. Then we clicked the “Add Certificates” button. Then we select the local certificate file and the password to install it into this azure service.   The final step would be back to our Visual Studio and in the pulish dialog just click the OK button. The Visual Studio will upload our package and the configuration into our service with the remote desktop settings.   Remote Desktop Access to Azure Virtual Machine All things had been done, let’s have a look back on the Windows Azure Development Portal. If I selected the web role that I had just published we can see on the toolbar there’s a section named “Remote Access”. In this section the Enable checkbox had been checked which means this role has the Remote Desktop Access feature enabled. If we want to modify the access cerdentals we can simply click the Configure button. Then we can update the user name, password, certificates and the expiration date.   Let’s select the instance node under the web role. In this case I just created one instance for demo. We can see that when we selected the instance node, the Connect button turned enabled. After clicked this button there will be a RDP file downloaded. This is a Remote Desctop configuration file that we can use to access to our azure virtual machine. Let’s download it to our local machine and execute. We input the user name and password we specified when we published our application to azure and then click OK. There might be some certificates warning dislog appeared. This is because the certificates we use to encryption is not signed by a trusted provider. Just select OK in these cases as we know the certificate is safty to us. Finally, the virtual machine of Windows Azure appeared.   A Quick Look into the Azure Virtual Machine Let’s just have a very quick look into our virtual machine. There are 3 disks available for us: C, D and E. Disk C: Store the local resource, diagnosis information, etc. Disk D: System disk which contains the OS, IIS, .NET Frameworks, etc. Disk E: Sotre our application code. The IIS which hosting our webiste on Azure. The IP configuration of the azure virtual machine.   Summary In this post I covered one of the new feature of the Azure SDK 1.3 – Remote Desktop Access. We can set the access per service and all of the instances of this service could be accessed through the remote desktop tool. With this feature we can deep into the virtual machines of our instances to see the inner information such as the system event, IIS log, system information, etc. But we should pay attention to modify the system settings. 2 reasons from what I know for now: 1. If we have more than one instances against our service we should ensure that all system settings we modifed are applied to all instances/virtual machines. Otherwise, as the machines are under the azure load balance proxy our application process may doesn’t work due to the defferent settings between the instances. 2. When the virtual machine encounted some problem and need to be translated to another physical machine all settings we made would be disappeared.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Move "XP Mode" from Windows Virtual PC to VirtualBox?

    - by JoelFan
    I installed "XP Mode" in Windows 7 (which uses Windows Virtual PC to host XP). I have now discovered that VirtualBox, which I have installed on the same Windows 7 machine, refuses to run at the same time as Windows Virtual PC (it gives me an error about not running multiple visualization programs). Is there any way I can convert the "XP Mode" image so that it will run inside VirtualBox instead of Windows Virtual PC? That way I will be able to run XP as well as other VM's at the same time.

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  • How to get Virtual PC to recognize MIDI devices?

    - by bparker
    Hey all. I have an XP Pro virtual machine running inside Virtual PC 2007. My host machine is x64 Windows 7. I have a MIDI keyboard hooked up to my machine via a Turtle Beach USB to MIDI 1x1 cable. I have installed the driver and software on my host machine and ran a soundcheck, and everything appears to be working fine. Playback is sent to the MIDI device with no problems. However, when I attempt to install the driver and run a soundcheck in my XP virtual machine, the device is not found. Other USB devices (mouse, keyboard, flash drives) work fine in the virtual machine, but not they MIDI keyboard. I'm not sure what steps to take in order to troubleshoot the and get the VM to start recognizing the MIDI keyboard. Any help or suggestions would be greatly appreciated. Thanks.

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  • Windows 7 XP Mode - Is it possible to have multiple XP Mode Virtual PCs?

    - by STW
    Windows 7's XP Mode virtual PC supports some features that aren't 'stock' with an XP Virtual PC such as a different start-up dialog, no Shutdown button, etc. Possibly the most significant is that applications installed within the XP Mode VM appear within the Windows 7 start-menu. I have a need for multiple XP Mode VM's--is it possible to have 2 or more XP Mode VM's, or to otherwise enable these extra integration features in an XP Virtual PC?

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  • Windows 7 XP Mode - Is it possible to have multiple XP Mode Virtual PCs?

    - by Yoooder
    Win7's XP Mode virtual PC supports some features that aren't 'stock' with an XP Virtual PC such as a different start-up dialog, no Shutdown button, etc. Possibly the most significant is that applications installed within the XP Mode VM appear within the Windows 7 start-menu. I have a need for multiple XP Mode VM's--is it possible to have 2 or more XP Mode vm's, or to otherwise enable these extra integration features in an XP Virtual PC?

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  • How do UEFI and virtual machines relate to each other?

    - by Iterator
    I am trying to get my head around UEFI (Unified Extensible Firmware Interface) and it's not entirely clear to me how this affects virtual machines. Thus, there are three parts to this question: Is UEFI an advance in hardware support for virtualization? All other things being equal, would a machine with UEFI be more likely to run a virtual machine more efficiently than one without, or does UEFI cause any performance hits that negate any speed improvements from a virtual machine? Would the difference in execution be visible to code running in a virtual machine? (In theory, it shouldn't, but in practice?)

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  • Is there a way to pin a virtual PC VHD to the Windows 7 taskbar?

    - by Corey
    I have a virtual HD for Windows XP mode, and wanted to pin it to the task bar. However, trying to pin the shortcut to the VHD file actually pins the "virtual machines" folder instead. Clicking on it opens the explorer window and I have to click on the VHD to actually open Windows XP. It does know I'm trying to pin the file, and if I right-click the taskbar icon, has the file under "pinned," but the default action is what's under "Task" (which is to open the virtual machines folder in explorer). Is there a way to pin the actual VHD to the taskbar, so it's just one click to restore the virtual machine?

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  • How to prevent response to who-has requests on virtual eth interface?

    - by user42881
    Hi, we use small embedded X86 linux servers equipped with a single physical ethernet port as a gateway for an IP video surveillance application. Each downstream IP cam is mapped to a separate virtual IP address like this: real eth0 IP address= 192.168.1.1, camera 1 (eth0:1) =192.168.1.61, camera 2 (eth0:2) =192.168.1.62, etc. etc. all on the same eth0 physical port. This approach works well, except that a specific third-party windows video recording application running on a separate PC on the same LAN, automatically pings the virtual IPs looking for unique who-has responses on system startup and, when it gets back the same eth0 MAC address for each virtual interface, freaks out and won't allow us to subsequently manually enter those addresses. The windows app doesn't mind, tho, if it receives no answer to the who-has ping. My question - how can we either (a) shut off the who-has responses just for the virtual eth0:x interfaces while keeping them for the primary physical eth0 port, or, in the alternative, spoof a valid but different MAC address for each virtual interface? Thanks!

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