I have a pretty big std::vector<matrix>, where matrix is a custom class defined by me. I would like to know how much memory has been allocated to that vector at a certain point in time. Is there any way of doing this in c++?
Or is my only shot, taking a look at the task monitor of windows/unix/whatever at execution time to estimate this?
We have a proprietary third-party library that we make calls into via an API. Through a series of API calls, this library manipulates specific sets of data. Prior to making these calls, there are some API calls that are necessary in order to initialize the library in preparation for a specific set of data. One of the calls tells the library to allocate some memory and then perform whatever initialization is required. This particular API call returns a pointer to char (char*) that is later used as an argument for a few other API calls. My question is... Is there a way, or maybe some kind of trick, to tell exactly how much memory was allocated? It doesn't matter whether or not the solution (if there is one) is C++ related, or some series of OS commands. FYI: We're running on Redhat Linux 6.2 and using GNU C++ 4.4.6.
View 5 Replies View RelatedSuppose if i code like this,
while( true ) {
int x;
// do some thing;
// break on some condition match;
}
whether memory is allocated for ints x one time or each time it hits int x.
For static variables when the memory will be allocated? During compilation or linking or loading time? In below program i am getting error :
(Error C2099: initializer is not a constant in microsoft visual studio) .
If i initialize x = 10 or any constant it works , why?
Code:
main() {
int i=10;
static int x = i;//error ?
if(x==i)
printf("Equal");
[Code] .....
I'm trying to free allocated memory for structure. It seems like free() gets only pointer and not regular types . my question is basic and simple – is passing pointer to free() frees the pointer or the variable it points at? or both?
View 2 Replies View RelatedI have a question about memory allocation.I have a function that calls a lot of object constructors, which in return these constructors will allocate a lot of memory.Now, in my program I am sure that if I first call this function , say it will call the constructor of 100 object.If I call this function again and again, I am sure that it will only call the constructor 100 times again, and thus I am sure that the memory allocated in the first call can be reused again.
How can I reuse the memory allocated in the first call?Can I use something like boost:object_pool so that I can tell the pool to restart from the begining and do not allocate extra memory, just use what you already have?
How can I view the number of bytes that have been allocated by using the malloc function?I tried:
mem = (float*)malloc(num*sizeof(float));
printf("The amount of memory allocated using malloc is %d.", mem);
Note: The variable "num" in my program is equal to 7.But every time I run the program, this value changes.
When declaring char array[10], memory is allocated for 10 1-bit memory locations. Is extra memory allocated for storing the address of array[0]? In expressions, is array equivalent to a pointer constant or is it an identifier for a memory cell containing the address of array[0]? In other words, is array a variable or an alias for &array[0]?
View 6 Replies View RelatedI am having issues freeing memory that I allocated when adding a node to a doubly linked list. I have tried adding free() at the end of the remove function from the list with no luck. I have tried using all sorts of temporary nodes and dummy nodes to free without losing node information. Have tried storing current node, moving to next one, then freeing the old current one, without luck. Everytime I try to free a node it destroys the list. It loses important node information and can no longer operate properly and I am met with all sorts of memory crashes. I will post my add and delete nodes functions here:
/**
* Adds a node to a given list
*
* @param q pointer a a list
* @param node pointer to the node to be added
*/
void list_add(list *q, path *node){
path *pn;
if(!(pn = (path*)malloc(sizeof(*pn)))){
perror("malloc");
exit(1);
[Code] ....
Those free's at the end are to get rid of nodes I malloced in find_path. This find_path works really well when run once lol. It finds shortest path and prints it no problem, but doing it over and over again will be problematic as it is leaking almost every bit of memory it uses />.
So in short, how to free an allocated node when I remove it from a list while still being able to use it? I have tried moving the remove function to different locations like the end of the file and still no luck. I even tried allocating a new current_node each iteration of while loop, using it, then freeing it at the end of the while loop and took out the allocation in the list_add() function. This didn't work either />. How to stop the leakage.
I am trying to store each value of a column from a text file into an dynamically allocated array, which needs to be globally declared for further usage in the program.The input textfile contains the following:
34932 13854 13854 2012-01-07
172098 49418 53269 2012-01-07
I have written the following code:
Code:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
}
[code]....
The commented printf line gives the entire values of the column, which proves that the file is correctly being read.But on compiling this program I get both compiler warnings and finally segmentation fault.
Having some frustrating issues trying to free memory from a dynamically allocated array of pointers to linked lists. I think the problem is in how I initialize the pointers to NULL. Is there a more elegant way to have the program recognize that the list is empty so it knows to create a head node for the linked list in the function 'add_end_stub_to_array'?
I ran the code through Valgrind and it says that memory is definitely lost from this array.
This is the structure definition.
Code: struct stub_edge {
int loc_id;
int anim_type;
int mkt;
struct stub_edge *next_node;
};
Here is the code snippet from main allocating and deallocating memory to the array.
Code:
struct stub_edge **stub_list = (struct stub_edge **)malloc( sizeof(struct stub_edge *) * 12);
for (i = 0; i < 12; i++)
{
stub_list[i] = (struct stub_edge *)malloc(sizeof(struct stub_edge));
stub_list[i] = NULL;
}
stub_list = add_end_stub_to_array(end_stubs, stub_list);
destroy_end_stub_array(stub_list);
Here the function for adding nodes to the lists by reading through a dynamically allocated 2D array. (The end_stubs array is ordered by month and each linked list represents events occuring within the month).
Code:
struct stub_edge **add_end_stub_to_array(int **end_stubs, struct stub_edge **list)
{
long int i = 0;
int mon = 0;
struct stub_edge *current_node1;
struct stub_edge *new_node1;
int break1 = 0;
while(i < num_edges && break1 == 0 && mon < 12)
[Code]...
Here is the function for freeing memory from the list.
Code:
void destroy_end_stub_array(struct stub_edge **list)
{
if(list != NULL)
{
int mon = 0;
struct stub_edge *current_node1;
struct stub_edge *new_node1;
for(mon = 0; mon < 12; mon++)
[Code]...
Pointers point to an address in memory. What if I used 3 pointers: 2 to mark the first/last nodes, and the third to mark the current node being referenced? I would wrap it in a class (to make the memory management automatic, of course), but is this practical?? maybe some pseudo code will get the juices flowing:
template<class type>
class supercondensed_list{
public:
supercondensed_list();
~supercondensed_list();
[code].....
Any things I should take into consideration? I'm not exactly the most experienced with pointers, and manually managing memory, but I think it's worth trying. If this works, then my programs should, in theory, be 100% memory efficient.
I am trying to write a basic editor program and one of the parts asks me to "process dot commands that move point in whole line increments"
Earlier it says that a point is interpreted as specifying the location between characters rather than the characters themselves. and i need to use this to implements the following:
< moves point to the beginning of the document. > moves point to the end of the document. p moves point to the beginning of the previous line. n moves point to the beginning of the next line. k deletes the current line and leaves point at the beginning of the following line.
(there was a previous part before this so i already have some code that works) and in this part I'm trying to do a switch case
ie
for
< , >, p , n and k
I guess my question is how do i make this "point" need. Ive been using vectors, so the point needs to be somewhere inside the vector. I don't think ill be able to do what i need to do with out the point.
I've got a struct called Node that contains, among other things, a pointer to a vector of pgm objects. (pgm is a class i've created)
struct Node {
int label;
vector <pgm> *ptr;
Node* lessNode;
Node* moreNode;
};
in another class, i create a vector and a Node and am having trouble assigning the pointer in the Node to point to my new vector.
vector <pgm> lessData;
Node* left;
left->ptr=&lessData;
This all compiles ok, but the last line in the code above causes a segmentation fault. I should mention Node is declared on its own in Node.h and what pgm is. including pgm.h in node.
My question is this: Is it possible to determine where functions are stored at compile time, so that at run time you can pass the memory address as a pointer to the interrupt handler so that it can directly call the function at memory location 'X'?
The newest project I'm working on would require to either somehow capture these addresses or to find a work-around so that instead of passing the pointer to the interrupt handler, the software would then need to be able to be non-interruptable.
This code work perfectly, as follows.
Code #A:
#include <iostream>
#include <cstring>
#include <vector>
using namespace std;
typedef std::vector <void *> gr_vector_void_star;
gr_vector_void_star output_items;
[Code] .....
Output of above code #A:
char * sentence = "Angel";
for (int i=0; i < 5; i++)
{ out[i] = sentence[i]; } // error: invalid conversion from 'char' to 'char*' [-fpermissive]
It fails to compile with error message "invalid conversion from 'char' to 'char*'".
I have a program which call only one time malloc at the start of the program. When running, I see with 'process-explorer.exe' that memory is growing in little steps. Is this normal? why?
Using Windows 7
I am trying to pop the element on a vector off and return its value at the same time
vector.push_back();
Unfortunately that code only removes that element from the vector it does not return it
Is the only way to get the element and destroy it is to do this?
vector.back();
vector.pop_back();
I am trying to allocate a memory to vector but while running the program,my window appear and PC get halt state then i have to force fully shutdown my PC I found that due to the vector i am getting this problem.
#define SCOPEPLOT_MAXNUM_SAMPLES (1000000)
QHash<int, std::vector<double>*> m_sampleHash;
m_sampleHash.insert(1, new std::vector<double>(SCOPEPLOT_MAXNUM_SAMPLES));
std::vector<double>* vec_p = m_sampleHash.value(1);
for(int k = 0;k < numSamples;k++)
{
count++;
vec_p->at(k) = data_p[k];
}
vector<Type> vect; //allocates vect on stack and each of the Type (using std::allocator) also will be on the stack
vector<Type> *vect = new vector<Type>; //allocates vect on heap and each of the Type will be allocated on stack
vector<Type*> vect; //vect will be on stack and Type* will be on heap.
What I would like to know is, are all of the above statements true?
I had a question about memory allocation/how iterators work for a std::vector<foo> of a user defined class 'foo'. Say foo contains variables of variable size, so that each member of the std::vector<foo> does not require the same amount of memory space.
Does c++ allocate the same amount of memory for each element, equal to the amount of memory required for the largest element? Or does it use some sort of array of pointers pointing to the location of each element in the vector to make the iterator work? Or does it use some other method? I am wondering because I wrote a code which reads data from a binary files and stores most of it in std::vectors.
The code seems to be using significantly more memory than the sum of the size of all the binary files, and I am using vectors made up of the datatype within the binary files (float). So I was wondering if internally the code was allocating space for each vector element which is the size of the largest element as a way to handle indexing/iterators. I ran my code through a memory leak checker and it found no errors.
I have a vector of int,
Code:
vector<int> row_numbers{1,2,3,4,5,6,7,8,9};
I want to sequentially remove one element at a time starting with the first. When the second element is removed, the first element needs to go back in. The sequence would look like
Code:
// original vector, row_numbers.size()=9
row_numbers{1,2,3,4,5,6,7,8,9};
// trimmed vector, row_numbers_trim.size()=8
[Code] .......
I have been working under the assumption that the best method would be to have row_numbers remain untouched and work on a copy. For each step in the sequence, you would create row_numbers_trim as a copy of row_numbers, and then remove an element from row_numbers_trim.
Code:
// position being removed
int counter = 0;
// copy original vector
row_numbers_trim = row_numbers;
// remove the first element from the copy
row_numbers_trim(row_numbers_trim.begin()+counter);
All you would have to do here is to increment counter in a loop. is there a better way?
std vector seems to cause errors when destructing here some simplified code:
#include <stdlib.h>
#include <stdio.h>
#include <vector>
class Foo{
[Code]....
I asked a few questions a few weeks ago about vectors and the fact that their data is stored on the heap. When a function closes, anything in its scope is destroyed, if it's passed by reference it won't be destroyed since it's outside the scope.
I have a program where I create a vector in one function, then pass it by reference to another. When I test for memory leaks, I get told I have 1 memory leak in in my start() function, and one memory leak in my save() function.
It's just a simple program that creates a vector, populates it with some numbers, then saves the numbers in a file. If I'm passing my vector by reference to another function, do I need to manually do something to avoid memory leaks? I'll post the code below.
#include <vector>
#include <iostream>
#include <iomanip>
#include <cmath>
[Code].....
An attempt to create a class which is basically a mimic of vector<int> i don't seem to know how to delete pointer x in a destructor to free memory, also on pushback and pushfront methods, i can't free y when i implement delete[] y; y=NULL; i get some NULL out put when cout 'ing the object in main, why is that happening and how do i free memory y.
#include<iostream>
using namespace std;
class vectorOfint{
int* x;
int size;
public:
vectorOfint();
[Code] .....
I have one code that use MPI broadcast and I want to change it into Asynchronous Point to Point communication. I am newbie in Parallel programming. Looking for implementation of one simple same program in broadcast and P2P ?
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