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  • NSMutableDictionary, alloc, init and reiniting...

    - by Marcos Issler
    In the following code: //anArray is a Array of Dictionary with 5 objs. //here we init with the first NSMutableDictionary *anMutableDict = [[NSMutableDictionary alloc] initWithDictionary:[anArray objectAtIndex:0]]; ... use of anMutableDict ... //then want to clear the MutableDict and assign the other dicts that was in the array of dicts for (int i=1;i<5;i++) { [anMutableDict removeAllObjects]; [anMutableDict initWithDictionary:[anArray objectAtIndex:i]]; } Why this crash? How is the right way to clear an nsmutabledict and the assign a new dict? Thanks guy's. Marcos.

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  • An interesting case of delete and destructor (C++)

    - by Viet
    I have a piece of code where I can call destructor multiple times and access member functions even the destructor was called with member variables' values preserved. I was still able to access member functions after I called delete but the member variables were nullified (all to 0). And I can't double delete. Please kindly explain this. Thanks. #include <iostream> using namespace std; template <typename T> void destroy(T* ptr) { ptr->~T(); } class Testing { public: Testing() : test(20) { } ~Testing() { printf("Testing is being killed!\n"); } int getTest() const { return test; } private: int test; }; int main() { Testing *t = new Testing(); cout << "t->getTest() = " << t->getTest() << endl; destroy(t); cout << "t->getTest() = " << t->getTest() << endl; t->~Testing(); cout << "t->getTest() = " << t->getTest() << endl; delete t; cout << "t->getTest() = " << t->getTest() << endl; destroy(t); cout << "t->getTest() = " << t->getTest() << endl; t->~Testing(); cout << "t->getTest() = " << t->getTest() << endl; //delete t; // <======== Don't do it! Double free/delete! cout << "t->getTest() = " << t->getTest() << endl; return 0; }

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  • Finding leaks under GeneralBlock-16?

    - by erastusnjuki
    If ObjectAlloc cannot deduce type information for the block, it uses 'GeneralBlock'. Any strategies to get leaks from this block that may eliminate the need of my 'trial and error' methods that I use? The Extended Detail thing doesn't really do it for me as I just keep guessing.

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  • How to manipulate *huge* amounts of data

    - by Alejandro
    Hi there! I'm having the following problem. I need to store huge amounts of information (~32 GB) and be able to manipulate it as fast as possible. I'm wondering what's the best way to do it (combinations of programming language + OS + whatever you think its important). The structure of the information I'm using is a 4D array (NxNxNxN) of double-precission floats (8 bytes). Right now my solution is to slice the 4D array into 2D arrays and store them in separate files in the HDD of my computer. This is really slow and the manipulation of the data is unbearable, so this is no solution at all! I'm thinking on moving into a Supercomputing facility in my country and store all the information in the RAM, but I'm not sure how to implement an application to take advantage of it (I'm not a professional programmer, so any book/reference will help me a lot). An alternative solution I'm thinking on is to buy a dedicated server with lots of RAM, but I don't know for sure if that will solve the problem. So right now my ignorance doesn't let me choose the best way to proceed. What would you do if you were in this situation? I'm open to any idea. Thanks in advance!

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  • Oracle Database In-Memory

    - by Mike.Hallett(at)Oracle-BI&EPM
    Normal 0 false false false EN-GB X-NONE X-NONE Larry Ellison unveiled the next major milestone in database technology, Oracle Database In-Memory, on June 10, 2014. Oracle Database In-Memory will be generally available in July 2014 and can be used with all hardware platforms on which Oracle Database 12c is supported. This option will accelerate database performance by orders of magnitude for analytics, data warehousing, and reporting while also speeding up online transaction processing (OLTP). It allows any existing Oracle Database-compatible application to automatically and transparently take advantage of columnar in-memory processing, without additional programming or application changes. Benefits Fast ad-hoc analytics without the need to pre-create indexes Completely transparent to existing applications Faster mixed workload OLTP No database size limit Industrial strength availability and security Robustness and maturity of Oracle Database 12c To find out more see Oracle Database In-Memory Comment from Rittman Mead on Oracle In-Memory Option Launch  ... and I will let you know how this unfolds in regards to advantages for OBI11g and Exalytics and Big Data over the coming months. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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  • Remove pointer object whose reference is mantained in three different lists

    - by brainydexter
    I am not sure how to approach this problem: 'Player' class mantains a list of Bullet* objects: class Player { protected: std::list< Bullet* > m_pBullet_list; } When the player fires a Bullet, it is added to this list. Also, inside the constructor of bullet, a reference of the same object is updated in CollisionMgr, where CollisionMgr also mantains a list of Bullet*. Bullet::Bullet(GameGL*a_pGameGL, Player*a_pPlayer) : GameObject( a_pGameGL ) { m_pPlayer = a_pPlayer; m_pGameGL->GetCollisionMgr()->AddBullet(this); } class CollisionMgr { void AddBullet(Bullet* a_pBullet); protected: std::list< Bullet*> m_BulletPList; } In CollisionMgr.Update(); based on some conditions, I populate class Cell which again contain a list of Bullet*. Finally, certain conditions qualify a Bullet to be deleted. Now, these conditions are tested upon while iterating through a Cell's list. So, if I have to delete the Bullet object, from all these places, how should I do it so that there are no more dangling references to it? std::list< Bullet*>::iterator bullet_it; for( bullet_it = (a_pCell->m_BulletPList).begin(); bullet_it != (a_pCell->m_BulletPList).end(); bullet_it++) { bool l_Bullet_trash = false; Bullet* bullet1 = *bullet_it; // conditions would set this to true if ( l_Bullet_Trash ) // TrashBullet( bullet1 ); continue; } Also, I was reading about list::remove, and it mentions that it calls the destructor of the object we are trying to delete. Given this info, if I delete from one list, the object does not exist, but the list would still contain a reference to it..How do I handle all these problems ? Can someone please help me here ? Thanks PS: If you want me to post more code or provide explanation, please do let me know.

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  • JVMTI: FollowReferences : how to skip Soft/Weak/Phantom references?

    - by Jayan
    I am writing a small code to detect number of objects left behind after certain actions in our tool. This uses FollowReferences() JVMTI-API. This counts instances reachable by all paths. How can I skip paths that included weak/soft/phantom reference? (IterateThroughHeap counts all objects at the moment, so the number is not fully reliable) Thanks, Jayan

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  • iPhone objective-c autoreleasing leaking

    - by okami
    I do this: NSString *fullpath = [[NSBundle mainBundle] pathForResource:@"text_file" ofType:@"txt"]; Why the following message appear? Is my code leaking? 2010-03-31 13:44:18.649 MJIPhone[2175:207] *** _NSAutoreleaseNoPool(): Object 0x3909ba0 of class NSPathStore2 autoreleased with no pool in place - just leaking Stack: (0x1656bf 0xc80d0 0xcf2ad 0xcee0e 0xd3327 0x2482 0x2426) 2010-03-31 13:44:18.653 MJIPhone[2175:207] *** _NSAutoreleaseNoPool(): Object 0x390b0b0 of class NSPathStore2 autoreleased with no pool in place - just leaking Stack: (0x1656bf 0xc80d0 0xc7159 0xd0c6f 0xd3421 0x2482 0x2426) 2010-03-31 13:44:18.672 MJIPhone[2175:207] *** _NSAutoreleaseNoPool(): Object 0x390d140 of class NSCFString autoreleased with no pool in place - just leaking Stack: (0x1656bf 0xc6e62 0xcec1b 0xd4386 0x24ac 0x2426)

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  • Why does accessing a member of a malloced array of structs seg fault?

    - by WSkinner
    I am working through Learn C The Hard Way and am stumped on something. I've written a simplified version of the problem I am running into to make it easier to get down to it. Here is the code: #include <stdlib.h> #define GROUP_SIZE 10 #define DATA_SIZE 64 struct Dummy { char *name; }; struct Group { struct Dummy **dummies; }; int main() { struct Group *group1 = malloc(sizeof(struct Group)); group1->dummies = malloc(sizeof(struct Dummy) * GROUP_SIZE); struct Dummy *dummy1 = group1->dummies[3]; // Why does this seg fault? dummy1->name = (char *) malloc(DATA_SIZE); return 0; } when I try to set the name pointer on one of my dummies I get a seg fault. Using valgrind it tells me this is uninitialized space. Why is this?

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  • Tomcat memory issue

    - by user305210
    Hello, I have noticed that my application that is running on Tomcat 5 starts with 1gig of memory and as soon as it starts receiving requests from client, the memory starts dropping until it is down to 100MBs and troubles start from there. I am looking at /manager/status page of tomcat under JVM section where "Free Memory", "Total Memory", "Max Memory" is listed. Is this an indicator of memory leak? Memory does not seem to be freed-up automatically even if there are no requests coming from client machines.

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  • Page Fault Interrupt Problems

    - by Vikas
    This is a statement referring to problem caused by page fault:(from Silberschatz 7th ed P-310 last para) 'We cant simply restart instructions when instruction modifies several different location Ex:when a instruction moves 256 bytes from source to dest and either src or dest straddles on page boundary , then,after a partial move, if a page fault occurs, 'we can't simply restart the instructions' My question is Why not? Simply restart the instruction again do the same copy after page is in. Is there any problem in it?

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  • Which type of file parsing easiest and efficient and good ?(html,pdf,csv,text)

    - by Harikrishna
    I want to parse the html file, pdf file, csv file and text file. Now parsing for which type of file (specified above) is easiest and efficient ? Like parsing for html file is easiest and efficient OR parsing for pdf file is easiest and efficient OR parsing for csv file is easiest and efficient ? I am asking this question because I want to parse pdf ,html ,csv and text file through common parsing code if possible. And now suppose if parsing for html is easiest and efficient then : I will write the parsing code for html file and will try to convert pdf file to the html file(if possible)so the code written for parsing html file will also work for pdf file also. And thus I will try to convert pdf,csv and text file to html file.And write the code for parsing html file and thus this code will parse html,pdf,csv and text file. Suppose if parsing for pdf is easiest and efficient then : I will convert html,csv and text file to pdf and write the code for parsing pdf file.So the code for parsing pdf file can parse html,csv and text file. So my question is (1) Which type of file parsing is easiest and efficient (pdf,csv,html,text) ? (2) And converting files(pdf,text,html,csv) to eachother is possible. Like if html parsing easiest then pdf to html,text to html and csv to html.

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  • Condition Variable in Shared Memory - is this code POSIX-conformant?

    - by GrahamS
    We've been trying to use a mutex and condition variable to synchronise access to named shared memory on a LynuxWorks LynxOS-SE system (POSIX-conformant). One shared memory block is called "/sync" and contains the mutex and condition variable, the other is "/data" and contains the actual data we are syncing access to. We're seeing failures from pthread_cond_signal() if both processes don't perform the mmap() calls in exactly the same order, or if one process mmaps in some other piece of shared memory before it mmaps the sync memory. This example code is about as short as I can make it: #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <sys/file.h> #include <stdlib.h> #include <pthread.h> #include <errno.h> #include <iostream> #include <string> using namespace std; static const string shm_name_sync("/sync"); static const string shm_name_data("/data"); struct shared_memory_sync { pthread_mutex_t mutex; pthread_cond_t condition; }; struct shared_memory_data { int a; int b; }; //Create 2 shared memory objects // - sync contains 2 shared synchronisation objects (mutex and condition) // - data not important void create() { // Create and map 'sync' shared memory int fd_sync = shm_open(shm_name_sync.c_str(), O_CREAT|O_RDWR, S_IRUSR|S_IWUSR); ftruncate(fd_sync, sizeof(shared_memory_sync)); void* addr_sync = mmap(0, sizeof(shared_memory_sync), PROT_READ|PROT_WRITE, MAP_SHARED, fd_sync, 0); shared_memory_sync* p_sync = static_cast<shared_memory_sync*> (addr_sync); // init the cond and mutex pthread_condattr_t cond_attr; pthread_condattr_init(&cond_attr); pthread_condattr_setpshared(&cond_attr, PTHREAD_PROCESS_SHARED); pthread_cond_init(&(p_sync->condition), &cond_attr); pthread_condattr_destroy(&cond_attr); pthread_mutexattr_t m_attr; pthread_mutexattr_init(&m_attr); pthread_mutexattr_setpshared(&m_attr, PTHREAD_PROCESS_SHARED); pthread_mutex_init(&(p_sync->mutex), &m_attr); pthread_mutexattr_destroy(&m_attr); // Create the 'data' shared memory int fd_data = shm_open(shm_name_data.c_str(), O_CREAT|O_RDWR, S_IRUSR|S_IWUSR); ftruncate(fd_data, sizeof(shared_memory_data)); void* addr_data = mmap(0, sizeof(shared_memory_data), PROT_READ|PROT_WRITE, MAP_SHARED, fd_data, 0); shared_memory_data* p_data = static_cast<shared_memory_data*> (addr_data); // Run the second process while it sleeps here. sleep(10); int res = pthread_cond_signal(&(p_sync->condition)); assert(res==0); // <--- !!!THIS ASSERT WILL FAIL ON LYNXOS!!! munmap(addr_sync, sizeof(shared_memory_sync)); shm_unlink(shm_name_sync.c_str()); munmap(addr_data, sizeof(shared_memory_data)); shm_unlink(shm_name_data.c_str()); } //Open the same 2 shared memory objects but in reverse order // - data // - sync void open() { sleep(2); int fd_data = shm_open(shm_name_data.c_str(), O_RDWR, S_IRUSR|S_IWUSR); void* addr_data = mmap(0, sizeof(shared_memory_data), PROT_READ|PROT_WRITE, MAP_SHARED, fd_data, 0); shared_memory_data* p_data = static_cast<shared_memory_data*> (addr_data); int fd_sync = shm_open(shm_name_sync.c_str(), O_RDWR, S_IRUSR|S_IWUSR); void* addr_sync = mmap(0, sizeof(shared_memory_sync), PROT_READ|PROT_WRITE, MAP_SHARED, fd_sync, 0); shared_memory_sync* p_sync = static_cast<shared_memory_sync*> (addr_sync); // Wait on the condvar pthread_mutex_lock(&(p_sync->mutex)); pthread_cond_wait(&(p_sync->condition), &(p_sync->mutex)); pthread_mutex_unlock(&(p_sync->mutex)); munmap(addr_sync, sizeof(shared_memory_sync)); munmap(addr_data, sizeof(shared_memory_data)); } int main(int argc, char** argv) { if(argc>1) { open(); } else { create(); } return (0); } Run this program with no args, then another copy with args, and the first one will fail at the assert checking the pthread_cond_signal(). But change the open() function to mmap() the "/sync" memory first and it will all work fine. This seems like a major bug in LynxOS but LynuxWorks claim that using mutex and condition variable in this way is not covered by the POSIX standard, so they are not interested. Can anyone determine if this code does violate POSIX? Or does anyone have any convincing documentation that it is POSIX compliant?

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