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• Should *'s go next to the type or the variable name? [closed]

  - by derekerdmann

  Possible Duplicate: int* i; or int *i; or int * i; When working in C or C++, how should pointers be declared? Like this: char* derp; or this: char *derp; I typically use the first method, because the variable is a character pointer, but I know that it can create confusion when declaring multiple variables at once: char* herp, derp; herp becomes a character pointer, while derp is just a character. I know it often comes down to coding style, but which one is "better?" Should I sacrifice clarity to eliminate potential confusion?

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• Lvalue required error [migrated]

  - by ankur.trapasiya

  While working with pointers i wrote the following code, int main() { int a[]={10,20,30,40,50}; int i; for(i=0;i<5;i++) { printf("\n%d",*a); a++; } return 0; } Now as per my understanding array name itself is an address in c and the pointer arithmetic done is here is correct as per my knowledge. But when i try to run the code it is giving me "Lvalue Required" error. So what is the exact reason for occuring Lvalue required error because before this also i have come across situations where this error is there. Secondly why the arithmetic on the pointer is not legal here in this case?

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• Smart Array P400 - Accelerator Replacement Battery Failure

  - by inflammable

  TL;DR - Is the immediate failure of a replacement battery, for a failed battery, on a battery backed accelerator for a Smart Array P400 controller a common occurrence? Or are we likely to have an storage controller with an impending and critical fault? We have a slightly confusing situation with a Smart Array P400 storage controller with the 512mb battery backed accelerator addon on an HP DL380 server. The storage controller is (afaik) running the latest firmware and driver: Model: Smart Array P400 Controller Status: OK Firmware Version: 7.24 Serial Number: *snip* Rebuild Priority: Medium Expand Priority: Medium Number Of Ports: 2 The storage diagnostic (both on the both boot-up screen for the controller and within the 'Management Homepage' and the 'HP Array Diagnostic Utility') recently starting showing the following status a fault for the battery for the accelerator: Accelerator Status: Temporarily Disabled Error Code: Cache Disabled Low Batteries Serial Number: *snip* Total Memory: 524288 KB Read Cache: 25% Write Cache: 75% Battery Status: Failed Read Errors: 0 Write Errors: 0 We replaced the battery with a new unit (a visual inspection of the P400 card showing nothing unusual) and saw the same fault - but expected this to disappear over the course of a few hours/days as it charged. This didn't happy, and the fault status remains the same as above. Given the battery is a genuine part from HP, I wouldn't have expected a replacement battery to fail straight away, or to be dead-on-arrival (is that naivety on my part?). Is the immediate failure of a replacement battery, for a failed battery, on a battery backed accelerator a common occurrence? Or are we likely to have an storage controller with an impending and critical fault? Is there any diagnostic that could tell me more about the failed battery, without cracking the server open again? Many thanks!

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• Smart card driven membership and door entry system

  - by Rob G

  I'm looking at putting in a smart card driven system at my local sports club (which doesn't have oodles of money), and since they're willing to pay for hardware, and I'm willing to do the technical setup, I was wondering if anyone had any experience in setting something like this up. Writing any software needed is not the problem, I've pretty much got that covered with various open source projects out there and custom code I'll write, but it's more the hardware side I'm not too sure about and I'm looking for advice from people out there. I'm sure there are numerous complications, but on the surface it looks fairly simple. I'd basically like to enable members to swipe/touch a smart card at the door to gain entry to the club, walk up to a touch screen PC and swipe/touch a card reader there to "login" to the system I create, which will allow them to book club facilities etc. I may even want that same card to then activate things like lights or music when they enter the room they've booked. Pretty Eutopian I know, but still, we'd like to get as close as we can. As I said, the software shouldn't be a problem, and on the hardware side, so far I'm looking at: All in one touch screen PC running Windows 7 or Ubuntu USB card reader (not sure which one to buy) Smart Cards (again, never bought these before) Door/lighting hardware that could be triggered (not sure here either) If anyone has any advice on implementing something like this - especially the items I'm not sure about above, and of course anything I've missed out that's crucial, I'd be most grateful. Recommended hardware that you've used for something like this would be fantastic!

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• How to @synthesize a C-Style array of pointers?

  - by Peter Hajas

  I have a property defined in a class like so: @interface myClass UIImageView *drawImage[4]; ... @property (nonatomic, retain) UIImageView **drawImage; ... @synthesize drawImage; // This fails to compile I have found similar questions on StackOverflow and elsewhere, but none that really address this issue. What is the most Objective-C kosher way to do this?

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• Pointers, am I doing them correctly? Objective-c/cocoa

  - by Chris

  I have this in my @interface struct track currentTrack; struct track previousTrack; int anInt; Since these are not objects, I do not have to have them like int* anInt right? And if setting non-object values like ints, boolean, etc, I do not have to release the old value right (assuming non-GC environment)? The struct contains objects: typedef struct track { NSString* theId; NSString* title; } *track; Am I doing that correctly? Lastly, I access the struct like this: [currentTrack.title ...]; currentTrack.theId = @"asdf"; //LINE 1 I'm also manually managing the memory (from a setter) for the struct like this: [currentTrack.title autorelease]; currentTrack.title = [newTitle retain]; If I'm understanding the garbage collection correctly, I should be able to ditch that and just set it like LINE 1 (above)? Also with garbage collection, I don't need a dealloc method right? If I use garbage collection does this mean it only runs on OS 10.5+? And any other thing I should know before I switch to garbage collected code? Sorry there are so many questions. Very new to objective-c and desktop programming. Thanks

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• Using `<List>` when dealing with pointers in C#.

  - by Gorchestopher H

  How can I add an item to a list if that item is essentially a pointer and avoid changing every item in my list to the newest instance of that item? Here's what I mean: I am doing image processing, and there is a chance that I will need to deal with images that come in faster than I can process (for a short period of time). After this "burst" of images I will rely on the fact that I can process faster than the average image rate, and will "catch-up" eventually. So, what I want to do is put my images into a <List> when I acquire them, then if my processing thread isn't busy, I can take an image from that list and hand it over. My issue is that I am worried that since I am adding the image "Image1" to the list, then filling "Image1" with a new image (during the next image acquisition) I will be replacing the image stored in the list with the new image as well (as the image variable is actually just a pointer). So, my code looks a little like this: while (!exitcondition) { if(ImageAvailabe()) { Image1 = AcquireImage(); ImgList.Add(Image1); } if(ImgList.Count 0) { ProcessEngine.NewImage(ImgList[0]); ImgList.RemoveAt(0); } } Given the above, how can I ensure that: - I don't replace all items in the list every time Image1 is modified. - I don't need to pre-declare a number of images in order to do this kind of processing. - I don't create a memory devouring monster. Any advice is greatly appreciated.

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• how to Clean up(destructor) a dynamic Array of pointers??

  - by Ahmed Sharara

  Is that Destructor is enough or do I have to iterate to delete the new nodes?? #include "stdafx.h" #include<iostream> using namespace std; struct node{ int row; int col; int value; node* next_in_row; node* next_in_col; }; class MultiLinkedListSparseArray { private: char *logfile; node** rowPtr; node** colPtr; // used in constructor node* find_node(node* out); node* ins_node(node* ins,int col); node* in_node(node* ins,node* z); node* get(node* in,int row,int col); bool exist(node* so,int row,int col); //add anything you need public: MultiLinkedListSparseArray(int rows, int cols); ~MultiLinkedListSparseArray(); void setCell(int row, int col, int value); int getCell(int row, int col); void display(); void log(char *s); void dump(); }; MultiLinkedListSparseArray::MultiLinkedListSparseArray(int rows,int cols){ rowPtr=new node* [rows+1]; colPtr=new node* [cols+1]; for(int n=0;n<=rows;n++) rowPtr[n]=NULL; for(int i=0;i<=cols;i++) colPtr[i]=NULL; } MultiLinkedListSparseArray::~MultiLinkedListSparseArray(){ // is that destructor enough?? cout<<"array is deleted"<<endl; delete [] rowPtr; delete [] colPtr; }

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• Dereferencing deleted pointers always result in an Access Violation ??

  - by m3rLinEz

  I have a very simple C++ code here: char *s = new char[100]; strcpy(s, "HELLO"); delete [] s; int n = strlen(s); If I run this code from Visual C++ 2008 by pressing F5 (Start Debugging,) this always result in crash (Access Violation.) However, starting this executable outside the IDE, or using the IDE's Ctrl+F5 (Start without Debugging) doesn't result in any crash. What could be the difference? I also want to know if it's possible to stably reproduce the Access Violation crash caused from accessing deleted area? Is this kind of crash rare in real-life?

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• C++ vector of strings, pointers to functions, and the resulting frustration.

  - by Kyle

  So I am a first year computer science student, for on of my final projects, I need to write a program that takes a vector of strings, and applies various functions to these. Unfortunately, I am really confused on how to use pointer to pass the vector from function to function. Below is some sample code to give an idea of what I am talking about. I also get an error message when I try to deference any pointer. thanks. #include <iostream> #include <cstdlib> #include <vector> #include <string> using namespace std; vector<string>::pointer function_1(vector<string>::pointer ptr); void function_2(vector<string>::pointer ptr); int main() { vector<string>::pointer ptr; vector<string> svector; ptr = &svector[0]; function_1(ptr); function_2(ptr); } vector<string>::pointer function_1(vector<string>::pointer ptr) { string line; for(int i = 0; i < 10; i++) { cout << "enter some input ! \n"; // i need to be able to pass a reference of the vector getline(cin, line); // through various functions, and have the results *ptr.pushback(line); // reflectedin main(). But I cannot use member functions } // of vector with a deferenced pointer. return(ptr); } void function_2(vector<string>::pointer ptr) { for(int i = 0; i < 10; i++) { cout << *ptr[i] << endl; } }

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• Pointers to a typed variable in C#: Interfase, Generic, object or Class? (Boxing/Unboxing)

  - by PaulG

  First of all, I apologize if this has been asked a thousand times. I read my C# book, I googled it, but I can't seem to find the answer I am looking for, or I am missing the point big time. I am very confused with the whole boxing/unboxing issue. Say I have fields of different classes, all returning typed variables (e.g. 'double') and I would like to have a variable point to any of these fields. In plain old C I would do something like: double * newVar; newVar = &oldVar; newVar = &anotherVar; ... In C#, it seems I could do an interfase, but would require that all fields be properties and named the same. Breaks apart when one of the properties doesn't have the same name or is not a property. I could also create a generic class returning double, but seems a bit absurd to create a class to represent a 'double', when a 'double' class already exists. If I am not mistaken, it doesn't even need to be generic, could be a simple class returning double. I could create an object and box the typed variable to the newly created object, but then I would have to cast every time I use it. Of course, I always have the unsafe option... but afraid of getting to unknown memory space, divide by zero and bring an end to this world. None of these seem to be the same as the old simple 'double * variable'. Am I missing something here?

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• Incorrect data when passing pointer a list of pointers to a function. (C++)

  - by Phil Elm

  I'm writing code for combining data received over multiple sources. When the objects received (I'll call them MyPacket for now), they are stored in a standard list. However, whenever I reference the payload size of a partial MyPacket, the value shows up as 1 instead of the intended size. Here's the function code: MyPacket* CombinePackets(std::list<MyPacket*>* packets, uint8* current_packet){ uint32 total_payload_size = 0; if(packets->size() <= 0) return NULL; //For now. std::list<MyPacket*>::iterator it = packets->begin(); //Some minor code here, not relevant to the problem. for(uint8 index = 0; index < packets->size(); index++){ //(*it)->GetPayloadSize() returns 1 when it should show 1024. I've tried directly accessing the variable and more, but I just can't get it to work. total_payload_size += (*it)->GetPayloadSize(); cout << "Adding to total payload size value: " << (*it)->GetPayloadSize() << endl; std::advance(it,1); } MyPacket* packet = new MyPacket(); //Byte is just a typedef'd unsigned char. packet->payload = (byte) calloc(total_payload_size, sizeof(byte)); packet->payload_size = total_payload_size; it = packets->begin(); //Go back to the beginning again. uint32 big_payload_index = 0; for(uint8 index = 0; index < packets->size(); index++){ if(current_packet != NULL) *current_packet = index; for(uint32 payload_index = 0; payload_index < (*it)->GetPayloadSize(); payload_index++){ packet->payload[big_payload_index] = (*it)->payload[payload_index]; big_payload_index++; } std::advance(it,1); } return packet; } //Calling code std::list<MyPacket*> received = std::list<MyPacket*>(); //The code that fills it is here. std::list<MyPacket*>::iterator it = received.begin(); cout << (*it)->GetPayloadSize() << endl; // Outputs 1024 correctly! MyPacket* final = CombinePackets(&received,NULL); cout << final->GetPayloadSize() << endl; //Outputs 181, which happens to be the number of elements in the received list. So, as you can see above, when I reference (*it)-GetPayloadSize(), it returns 1 instead of the intended 1024. Can anyone see the problem and if so, do you have an idea on how to fix this? I've spent 4 hours searching and trying new solutions, but they all keep returning 1... EDIT:

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• Can I replace the binding operator with the smart match operator in Perl?

  - by sid_com

  How can I write this with the smart match operator (~~)? use 5.010; my $string = '12 23 34 45 5464 46'; while ( $string =~ /(\d\d)\s/g ) { say $1; }

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• what is function pointers in vbscript?

  - by Anil

  can some one clarify what is function pointers in vb script

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• Accessing smart card with Java

  - by Tom Brito

  I'm trying to learn about how does Java access smart cards, due to a project analysis. I wonder if there is any kind of virtual smart card which I could use to make some tests with Java? By the way, I've read about Java Card, and looks like it is used to run Java in cards, not to smart card data access, right?

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• Using std::bad_alloc for C pointers

  - by otibom

  I'm using a library written in C in a C++ project. I'd like to use C++ exceptions to handle C errors. In particular, it would be nice to have an exception thrown if an allocation fails. I can do this in constructors of classes which hold C-style pointers to C structs : if (c_object == NULL) throw std::bad_alloc(); But if the class is responsible for several C objects they are no ways of free-ing all already allocated pointers since the destructor isn't called. I have a feeling I could use smart-pointers, but I don't have much experience with them. What's more, I have to have access to the original C pointers to use the C api properly. Is there an elegant solution to this ?

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• Pointers and collection of pointers in C++. How to properly delete.

  - by Julen

  Hello, This is a newbe question but I have alwasy doubts with pointers in C++. This is the situation. I have a class A which as a collection (a vector actually) of pointers of class B. This same class A has another collection of pointers to class C. Finally the objects of class B have also a collection to pointers to class C which point to the same instances the class A points to. My question is, if I delete a member of class-C-type pointer in class B, what happens to the pointer in class A that points to the deleted instance of class C? How this situation has to be treated? Thanks a lot in advance! Julen.

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• Smart card authentication to a Cisco switch?

  - by murisonc

  We have our Cisco network devices configured to authenticate network administrators using their domain accounts via RADIUS running on a Windows 2008R2 server with the network protection role. This works great for logging into the switch via SSH when configuring the devices. We are now in the beginning stages of deploying smart cards for logins. Does anyone know of a way to login to a Cisco switch using a smart card instead of a domain username and password? The SSH client we are using is Putty. Workstations are Windows 7. RADIUS is running on Windows 2008R2. We are running our own certificate authority on Windows 2008; network is not connected to the Internet. We prefer to not have to purchase additional proprietary devices for this functionality.

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• APC UPS replace battery light and apcupsd reporting "replace battery"

  - by mgjk

  We have an APC Smart UPS 1500. The "Replace Battery" light is on, and apcupsd reports: Emergency! Batteries have failed on UPS xxxx. Change them NOW However, from this article, http://sturgeon.apcc.com/kbasewb2.nsf/for+external/f39c4312fcaf7b948525679a005ebb78?OpenDocument it seems that it's not so clear that the UPS battery needs to be replaced. Stranger, according to the information on the UPS, an 11 minute runtime at 42.9% load running at 27.7V isn't so bad. Any thoughts about what to try next? We're a non-profit, money is an object. It would be a shame to replace a battery with a year or so left in it. # apcaccess status APC : 001,041,1017 DATE : Thu Mar 29 13:01:41 EDT 2012 HOSTNAME : oreilly2 VERSION : 3.14.6 (16 May 2009) debian UPSNAME : xxxx CABLE : Custom Cable Smart MODEL : Smart-UPS 1500 UPSMODE : Stand Alone STARTTIME: Thu Mar 29 12:57:30 EDT 2012 STATUS : ONLINE LINEV : 112.3 Volts LOADPCT : 42.9 Percent Load Capacity BCHARGE : 100.0 Percent TIMELEFT : 11.0 Minutes MBATTCHG : 5 Percent MINTIMEL : 3 Minutes MAXTIME : 0 Seconds OUTPUTV : 112.3 Volts SENSE : High DWAKE : -01 Seconds DSHUTD : 090 Seconds LOTRANS : 106.0 Volts HITRANS : 127.0 Volts RETPCT : 000.0 Percent ITEMP : 23.8 C Internal ALARMDEL : Always BATTV : 27.7 Volts LINEFREQ : 60.0 Hz LASTXFER : No transfers since turnon NUMXFERS : 0 TONBATT : 0 seconds CUMONBATT: 0 seconds XOFFBATT : N/A SELFTEST : NO STATFLAG : 0x07000008 Status Flag SERIALNO : AS0603298896 BATTDATE : 2006-01-14 NOMOUTV : 120 Volts NOMBATTV : 24.0 Volts FIRMWARE : 601.3.D USB FW:1.5 APCMODEL : Smart-UPS 1500 END APC : Thu Mar 29 13:02:12 EDT 2012 Error when running upstest You are using a SMART cable type, so I'm entering SMART test mode mode.type = USB_UPS Setting up the port ... Hello, this is the apcupsd Cable Test program. This part of apctest is for testing Smart UPSes. Please select the function you want to perform. 1) Query the UPS for all known values 2) Perform a Battery Runtime Calibration 3) Abort Battery Calibration 4) Monitor Battery Calibration progress 5) Program EEPROM 6) Enter TTY mode communicating with UPS 7) Quit Select function number: 2 First ensure that we have a good link and that the UPS is functionning normally. Simulating UPSlinkCheck ... YWrote: Y Got: getline failed. Apparently the link is not up. Giving up.

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• How to handle failure to release a resource which is contained in a smart pointer?

  - by cj

  How should an error during resource deallocation be handled, when the object representing the resource is contained in a shared pointer? Smart pointers are a useful tool to manage resources safely. Examples of such resources are memory, disk files, database connections, or network connections. // open a connection to the local HTTP port boost::shared_ptr<Socket> socket = Socket::connect("localhost:80"); In a typical scenario, the class encapsulating the resource should be noncopyable and polymorphic. A good way to support this is to provide a factory method returning a shared pointer, and declare all constructors non-public. The shared pointers can now be copied from and assigned to freely. The object is automatically destroyed when no reference to it remains, and the destructor then releases the resource. /** A TCP/IP connection. */ class Socket { public: static boost::shared_ptr<Socket> connect(const std::string& address); virtual ~Socket(); protected: Socket(const std::string& address); private: // not implemented Socket(const Socket&); Socket& operator=(const Socket&); }; But there is a problem with this approach. The destructor must not throw, so a failure to release the resource will remain undetected. A common way out of this problem is to add a public method to release the resource. class Socket { public: virtual void close(); // may throw // ... }; Unfortunately, this approach introduces another problem: Our objects may now contain resources which have already been released. This complicates the implementation of the resource class. Even worse, it makes it possible for clients of the class to use it incorrectly. The following example may seem far-fetched, but it is a common pitfall in multi-threaded code. socket->close(); // ... size_t nread = socket->read(&buffer[0], buffer.size()); // wrong use! Either we ensure that the resource is not released before the object is destroyed, thereby losing any way to deal with a failed resource deallocation. Or we provide a way to release the resource explicitly during the object's lifetime, thereby making it possible to use the resource class incorrectly. There is a way out of this dilemma. But the solution involves using a modified shared pointer class. These modifications are likely to be controversial. Typical shared pointer implementations, such as boost::shared_ptr, require that no exception be thrown when their object's destructor is called. Generally, no destructor should ever throw, so this is a reasonable requirement. These implementations also allow a custom deleter function to be specified, which is called in lieu of the destructor when no reference to the object remains. The no-throw requirement is extended to this custom deleter function. The rationale for this requirement is clear: The shared pointer's destructor must not throw. If the deleter function does not throw, nor will the shared pointer's destructor. However, the same holds for other member functions of the shared pointer which lead to resource deallocation, e.g. reset(): If resource deallocation fails, no exception can be thrown. The solution proposed here is to allow custom deleter functions to throw. This means that the modified shared pointer's destructor must catch exceptions thrown by the deleter function. On the other hand, member functions other than the destructor, e.g. reset(), shall not catch exceptions of the deleter function (and their implementation becomes somewhat more complicated). Here is the original example, using a throwing deleter function: /** A TCP/IP connection. */ class Socket { public: static SharedPtr<Socket> connect(const std::string& address); protected: Socket(const std::string& address); virtual Socket() { } private: struct Deleter; // not implemented Socket(const Socket&); Socket& operator=(const Socket&); }; struct Socket::Deleter { void operator()(Socket* socket) { // Close the connection. If an error occurs, delete the socket // and throw an exception. delete socket; } }; SharedPtr<Socket> Socket::connect(const std::string& address) { return SharedPtr<Socket>(new Socket(address), Deleter()); } We can now use reset() to free the resource explicitly. If there is still a reference to the resource in another thread or another part of the program, calling reset() will only decrement the reference count. If this is the last reference to the resource, the resource is released. If resource deallocation fails, an exception is thrown. SharedPtr<Socket> socket = Socket::connect("localhost:80"); // ... socket.reset();

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• Error Ubuntu 11.10 despues de instalar [Error after installing Ubuntu 11.10]

  - by manue

  instale ubuntu 11.10, termino de instalar y no tiene nada, ni aplicaciones, ni esa barrita lateral de unity, no tiene nada, ni si quiera la barra donde aparece la hora; porque? y me aparece un cuadro diciendo que hay un error en el disco y que el fallo es inminente , que es? SMART no entiendo, ayuda Y en otro disco duro con windows xp sp3 se bloquea cuando lo instalo desde el live cd, y desde wubi aparece esto enter link description here que hacer? English translation (via Google Translate, edited) I have installed ubuntu 11.10, after finishing the installing there is nothing, no applications, no the sidebar called unity, there is nothing, not even the bar where time appears, why?. I get a box saying there is an error on the disk and that failure is imminent. What is SMART, I do not understand, help In my other hard drive, with windows xp sp3, it crashes when I try install from the live cd using wubi, this appears, what to do?

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• SSD becomes hot, disk failure warning

  - by Aegluin

  I have a two weeks old SSD (Kingston SSDnow 64GB). Yesterday, the computer shutdown twice and after rebooting I was bombarded with disk failure warnings. I usually take such warnings serious (and backed up), but skeptical. After cooling down, the laptop boots again and the only red Smart value was the temperature (Ubuntu did not show the temperature of failure, but the at that time 29°). After refreshing the Smart status and doing a "self test", everything is green. Before contacting Kingston support, I would like to know whether it could be due to a software issue: Is it possible that it is false alarm, and how can I check? I installed Ubuntu 12.04 32bit and took care of alignment. I supposed Ubuntu set up with optimal settings for SSDs, how can I check that there was no mistake? The current temperature is around 40-56°. Is such a temperature abnormal for SSDs? Output of sudo smartctl --all /dev/sda: http://pastebin.ubuntu.com/1175940/

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• Why can't Java/C# implement RAII?

  - by mike30

  Question: Why can't Java/C# implement RAII? Clarification: I am aware the garbage collector is not deterministic. So with the current language features it is not possible for an object's Dispose() method to be called automatically on scope exit. But could such a deterministic feature be added? My understanding: I feel an implementation of RAII must satisfy two requirements: 1. The lifetime of a resource must be bound to a scope. 2. Implicit. The freeing of the resource must happen without an explicit statement by the programmer. Analogous to a garbage collector freeing memory without an explicit statement. The "implicitness" only needs to occur at point of use of the class. The class library creator must of course explicitly implement a destructor or Dispose() method. Java/C# satisfy point 1. In C# a resource implementing IDisposable can be bound to a "using" scope: void test() { using(Resource r = new Resource()) { r.foo(); }//resource released on scope exit } This does not satisfy point 2. The programmer must explicitly tie the object to a special "using" scope. Programmers can (and do) forget to explicitly tie the resource to a scope, creating a leak. In fact the "using" blocks are converted to try-finally-dispose() code by the compiler. It has the same explicit nature of the try-finally-dispose() pattern. Without an implicit release, the hook to a scope is syntactic sugar. void test() { //Programmer forgot (or was not aware of the need) to explicitly //bind Resource to a scope. Resource r = new Resource(); r.foo(); }//resource leaked!!! I think it is worth creating a language feature in Java/C# allowing special objects that are hooked to the stack via a smart-pointer. The feature would allow you to flag a class as scope-bound, so that it always is created with a hook to the stack. There could be a options for different for different types of smart pointers. class Resource - ScopeBound { /* class details */ void Dispose() { //free resource } } void test() { //class Resource was flagged as ScopeBound so the tie to the stack is implicit. Resource r = new Resource(); //r is a smart-pointer r.foo(); }//resource released on scope exit. I think implicitness is "worth it". Just as the implicitness of garbage collection is "worth it". Explicit using blocks are refreshing on the eyes, but offer no semantic advantage over try-finally-dispose(). Is it impractical to implement such a feature into the Java/C# languages? Could it be introduced without breaking old code?

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• uninitialized local variable

  - by blitzeus

  This code compiles and runs though gives a Microsoft compiler error that I cant fix warning C4700: uninitialized local variable 'ptr4D' used. This is in the last line of the code, I think #include <iostream> using namespace std; const int DIM0 = 2, DIM1 = 3, DIM2 = 4, DIM3 = 5; void TestDeclar(); int main(){ TestDeclar(); cout << "Done!\n"; return 0; } void TestDeclar(){ //24 - array of 5 floats float xa[DIM3], xb[DIM3], xc[DIM3], xd[DIM3], xe[DIM3], xf[DIM3]; float xg[DIM3], xh[DIM3], xi[DIM3], xj[DIM3], xk[DIM3], xl[DIM3]; float xm[DIM3], xn[DIM3], xo[DIM3], xp[DIM3], xq[DIM3], xr[DIM3]; float xs[DIM3], xt[DIM3], xu[DIM3], xv[DIM3], xw[DIM3], xx[DIM3]; //6 - array of 4 pointers to floats float *ya[DIM2] = {xa, xb, xc, xd}, *yb[DIM2] = {xe, xf, xg, xh}; float *yc[DIM2] = {xi, xj, xk, xl}, *yd[DIM2] = {xm, xn, xo, xp}; float *ye[DIM2] = {xq, xr, xs, xt}, *yf[DIM2] = {xu, xv, xw, xx}; //2 - array of 3 pointers to pointers of floats float **za[DIM1] = {ya, yb, yc}; float **zb[DIM1] = {yd, ye, yf}; //array of 2 pointers to pointers to pointers of floats float ***ptr4D[DIM0] = {za, zb}; cout << &***ptr4D[DIM0] << '\n'; }

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• moving raid 10 to another identical server both on Smart Array 6i controllers

  - by SalimQrdl

  I have dead HP DL 380G4 with RAID 1+0 with 1 logical volume from 4x72GB drives on built-in Smart Array 6i 128Mb BBWC. It was shut down properly. It seems it was usual death for Proliant with ILO led 2,3,8 lighting. I want to move array to another identical server with same raid firmware level. What is the best strategy?: I have RAID 1+0 on bay 0 bay 1 bay 2 bay 3 As I understand bay0+bay1 are in RAID 1 , bay2+bay3 are in RAID 1, and both RAID 1 pairs are in RAID 0. So should I : Clear RAID config on new server, insert bay 0, bay 2 and power-on or Create RAID 1+0 with 1 logical volume from clear HDDs , and then poweroff ,remove HDDs and insert 2 HDDs(bay 0, bay 2) from old RAID 1+0. then power-on. (each hdd has its raid position info stored but may be could work on same config) According to documentation for Smart Array 6i it could be possible to migrate. however one requirement point is unclear for me Before you move drives, the following conditions must be met: • The array is in its original configuration. " What is orginal and non-original config for RAID 1+0? Another point "If you want to move an array to another controller, you must also consider the following additional limitations: • All drives in the array must be moved at the same time." I want to move one hdd from each RAID 1 pair. to have mirrors untouched just in case. Do they mean to move all 4 simultaniously? Smart Array 6i User Guide: Moving Drives and Arrays You can move drives to other ID positionson the same array controller. You can also move a complete arrayfrom one controller to another, even if the controllers are on different servers. Before you move drives, the following conditions must be met: • If moving thedrives to a different server, the new server must have enough empty bays to accommodate all the drives simultaneously. • The move will not result in more than 14 physical drives per controller channel. • No controller will be configured with more than 32 logical volumes. • The array has no failed or missing drives. • The array is in its original configuration. • The controller is not reading from or writing to any of the spare drives in the array. • The controller is not running capacity expansion, capacity extension, or RAID or stripe size migration. • The controller is using the latestfirmware version (recommended). If you want to move an array to another controller, you must also consider the following additional limitations: • All drives in the array must be moved at the same time. • In most cases, a moved array (and the logical drives that it contains) can still undergo arraycapacity expansion, logical drive capacity extension, or migration of RAID level orstripe size. When all the conditions have been met: Back up all data before removing any drives or changing configuration. This step is requiredif you are moving data-containing drives from a controller that does not have a battery-backed cache. Power down the system. If you are moving an array from a controller that contains a RAID ADG logical volume to a controller that does not support RAID ADG: Move the drives. Power up the system. If a 1724 POST message is displayed, drive positions were changed successfully and the configuration was updated. If a 1785 (NotConfigured)POST message is displayed: a. Power down the system immediately to prevent data loss. b. Return the drives to their original locations. c. Restore the data from backup, if necessary. Check the new drive configuration byrunning ORCA or ACU ("Configuring an Array" on page 9).

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