memory-management

问题 I have an array of pointers of CName objects. I have the following constructor which initializes my array to size one. Then when I add an object I grow the array by 1 and add the new object. It compiles fine, however when I try to print them I just get segmentation fault error. Can you look and see if I'm doing anything wrong? //constructor Names_Book::Names_Book() { grow_factor = 1; size = 0; cNames = (CName**)malloc(grow_factor * sizeof(CName*)); cNames[0] = NULL; } void Names_Book:

问题 I have some trouble with managing memory in my function. Valgrid says I'm having a memory leak after the convert-function. Could it be because of the data is not being properly released? I've tried to use temp-pointers, but my program either crashes or is not working properly. Have someone encountered this problem before? this->images.push_back(new cv::Mat()); //ID cv::threshold(*this->images[MASK], *this->images[ID], 0.0, 1.0, cv::THRESH_BINARY); this->images[ID]->convertTo(*this->images[ID]

问题 Lets consider following two codes First: for (int i=0;i<10000000;i++) { char* tab = new char[500]; delete[] tab; } Second: for (int i=0;i<10000000;i++) { char tab[500]; } The peak memory usage is almost the same, but the second code runs about 20 times faster than the first one. Question Is it because in first code array is stored on heap, and in the second one array is stored on stack? 回答1: Is it because in first code array is stored on heap, and in the second one array is stored on stack?

问题 Lets consider following two codes First: for (int i=0;i<10000000;i++) { char* tab = new char[500]; delete[] tab; } Second: for (int i=0;i<10000000;i++) { char tab[500]; } The peak memory usage is almost the same, but the second code runs about 20 times faster than the first one. Question Is it because in first code array is stored on heap, and in the second one array is stored on stack? 回答1: Is it because in first code array is stored on heap, and in the second one array is stored on stack?

问题 This question already has answers here : Closed 6 years ago . Possible Duplicate: NSString retain Count Is it possible that any object has its retain count in negative value ? I have this code NSString *str = [[NSString alloc] initWithString:@"Hello World"]; NSLog(@"String Retain Count: %i", [str retainCount]); this will return the retain count -1. Why this happened ? also I have done like this NSString *str = [[NSString alloc] init] still its return negative value in retain count . How this

问题 The first time a user opens my app I need to download lots of data. I get all of this data from the server in JSON form. Depending on the user, these JSON files can be anywhere from 10kb - 30mb each, and there are 10+ of them. I have no problems doing this when the JSONs have no more than 500 or so records, but like I said some have 10,000+ records and can be up to 30mb in size. When downloading the larger JSONs, my app allocs a ton of memory, until I eventually get memory warnings and the

问题 Looking at some example code and come across some zero-size array allocation. I created the following code snippet to clarify my question This is valid code: class T { }; int main(void) { T * ptr = new T[0]; return 0; } What is its use? Is ptr valid? Is this construct portable? 回答1: 5.3.4 in the C++ Standard: 6 Every constant-expression in a direct-new-declarator shall be an integral constant expression (5.19) and evaluate to a strictly positive value. The expression in a direct-new

问题 Looking at some example code and come across some zero-size array allocation. I created the following code snippet to clarify my question This is valid code: class T { }; int main(void) { T * ptr = new T[0]; return 0; } What is its use? Is ptr valid? Is this construct portable? 回答1: 5.3.4 in the C++ Standard: 6 Every constant-expression in a direct-new-declarator shall be an integral constant expression (5.19) and evaluate to a strictly positive value. The expression in a direct-new

问题 Is deleting a pointer same as freeing a pointer (that allocates the memory)? 回答1: Deleting a pointer (or deleting what it points to, alternatively) means delete p; delete[] p; // for arrays p was allocated prior to that statement like p = new type; It may also refer to using other ways of dynamic memory management, like free free(p); which was previously allocated using malloc or calloc p = malloc(size); The latter is more often referred to as "freeing", while the former is more often called

问题 Is deleting a pointer same as freeing a pointer (that allocates the memory)? 回答1: Deleting a pointer (or deleting what it points to, alternatively) means delete p; delete[] p; // for arrays p was allocated prior to that statement like p = new type; It may also refer to using other ways of dynamic memory management, like free free(p); which was previously allocated using malloc or calloc p = malloc(size); The latter is more often referred to as "freeing", while the former is more often called