memory

问题 I've a doubt about this question, not relatively to a specific language: when I write a class, maybe in C++ or Java, the memory for member function code is allocated once or at every instance? So, in certain cases, is it better to write them as static? thanks for replies 回答1: Nope, the data portion of the code is loaded separately from the executable section when the OS loads your program into memory. They reside usually into different memory regions (typically, the executable section is a

问题 Say I passed the address of the 2d array to a function along with its row and column of the 2d array. The function will treat the address of the 2d array as 1d array. (eg. int matrix[] ) If i execute below code: int** arr; arr = new int*[row]; for ( int i = 0; i < row; i++ ) { arr[i] = new int[column]; } Hypothetically, I think in a multi-threaded system, this may not allocate contiguous memory for the 2d array. Am I correct? However, I think in a single threaded system, this will allocate

问题 I have a problem when I run my code. My shmat fails and prints permission denied. I searched on google how to solve it but I can't. My code is the following: #include <stdio.h> #include <sys/ipc.h> #include <sys/shm.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <stdlib.h> #include <unistd.h> #define ERROR -1 int main ( int argc, char *argv[] ) { int shmid,key=50; int *val; int *x; int rw = -1; // 0 for write and 1 for read shmid = shmget ( key, sizeof( int ), IPC

问题 I realized a little C# porting of this application that allows to load libraries from memory/stream instead of using LoadLibrary API function that works through filesystem. After messing around a little bit with pointers and mimatching results... finally I have something working as intended. The only problem I have is that the call to DLLMain always fails (I tried it with Kernel32.dll and User32.dll). I can't understand why and I don't know how to debug the issue. Here is the main function of

问题 I am new to XSLT.I have an XML document and I am using the XSL for converting the XML in to an HTML table.The XML is response from an server to web client.In this case It is IE9 browser.The XSLT processing is done by browser.The number of "ch3" nodes ranges from 1 to 100000. Below is the sample code of what I am doing . In the below xsl code the variable is created in every loop.I like to know what is the effect of this creation on the browser memory.Also will this have any performance

问题 I am working with quite a large dataset (over 4 GB), which I imported in pandas . Quite some columns in this dataset are simple True/False indicators, and naturally the most memory-efficient way to store these would be using a bool dtype for this column. However, the column also contains some NaN values I want to preserve. Right now, this leads to the column having dtype float (with values 1.0 , 0.0 and np.nan ) or object, but they both use way too much memory. As an example: df = pd

问题 I am working with quite a large dataset (over 4 GB), which I imported in pandas . Quite some columns in this dataset are simple True/False indicators, and naturally the most memory-efficient way to store these would be using a bool dtype for this column. However, the column also contains some NaN values I want to preserve. Right now, this leads to the column having dtype float (with values 1.0 , 0.0 and np.nan ) or object, but they both use way too much memory. As an example: df = pd

问题 I have this test program. I don't know how to delete struct in the list using iterator. #include<iostream> #include<list> using namespace std; typedef struct Node { int * array; int id; }Node; void main() { list<Node> nlist; for(int i=0;i<3;i++) { Node * p = new Node;//how to delete is later? p->array = new int[5];//new array memset(p->array,0,5*sizeof(int)); p->id = i; nlist.push_back(*p);//push node into list } //delete each struct in list list<Node>::iterator lt = nlist.begin(); while( lt

问题 I'm currently supporting a VB6 application (that we are replacing, but it's a slow process!) that is running on several servers. Can anyone tell me please what the maximum amount of memory of VB6 process can address is? We are using a variety of operating systems: Windows Server 2003 32bit Windows Server 2008 64bit Windows Server 2008 R2 64bit I've tried using resources like this: https://blogs.msdn.microsoft.com/tom/2008/04/10/chat-question-memory-limits-for-32-bit-and-64-bit-processes/ But

问题 http://www.alex-ionescu.com/?p=50. I read the above post. The author explains why Windows x64 supports only 44-bit virtual memory address with singly linked list example. struct { // 8-byte header ULONGLONG Depth:16; ULONGLONG Sequence:9; ULONGLONG NextEntry:39; } Header8; The first sacrifice to make was to reduce the space for the sequence number to 9 bits instead of 16 bits, reducing the maximum sequence number the list could achieve. This still only left 39 bits for the pointer — a