is there any way to allocate more memory

[danialgood]

i have simulated a queue with pointer "*" but it dont allocate memory that i want and it overflows in about 10800 members
can i expand this limit ?

[Moschops]

Yes. Use the new command to allocate as much memory as you need.

[chenqi07]

I'm afraid 'new' can not solve this problem.
The problem is all about memory shortage, either phisical or virtual.
I don't think techniques on programming could solve it.
Could you please notify me if you fix it?
I'd like to know how.
Good Luck :)

[Moschops]

How do you know that's the problem? It's very easy to overflow the stack, and in such a case the solution is to use new.

[chenqi07]

I test both "malloc" and "new" in this machine. The result is almost the same. Here's the testing code.
P.S: I use g++ complier and Linux Mint11 OS.

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

#define A_MEGABYTE ( 1024 * 1024 )
#define MAX_ARRAY_NUM ( 1024 * 1024 )

int main()
{
int megabyte = A_MEGABYTE;
char *memArray[MAX_ARRAY_NUM];
for(int i = 0; i < MAX_ARRAY_NUM; i++)
{
memArray[i] = NULL; //initialize the pointer to be NULL
//memArray[i] = new char[megabyte];
memArray[i] = (char*)malloc(megabyte);
if ( memArray[i] != NULL ) //memory allocation success
{
sprintf(memArray[i], "Hello\n");
printf("%4d\t%s",i,memArray[i]);
}
else //memory allocation failed
{
printf("Memory alloctaion failed\n");
return 1;
}
}
return 0;
}

[Moschops]

Yes, your code exhausts the heap (runs out of actual physical memory). We still don't know if the OP was overflowing the stack or the heap.

[b2ee]

You are asking 1024G memory (1024*1024*1Megabyte) from your PC. Are you serious?


b2ee

[chenqi07]

A "toy" program to demonstrate that "malloc" and "new" can allocate almost the same size of memory.

[b2ee]

In my understanding about the memory using, the allocated memory must be not in continuous space and so it very possibly involved a lot of paging swapping to fetch some certain pointers. May can first try comment below: (it means avoiding using the memory firstly, then make sure the system can afford the assigning, then use it secondly)

if ( memArray[i] != NULL ) //memory allocation success
{
sprintf(memArray[i], "Hello\n");
printf("%4d\t%s",i,memArray[i]);
}
else //memory allocation failed
{
printf("Memory alloctaion failed\n");
return 1;
}

[hanst99]

I don't know what you are trying to put into your queue, but normally 10800 *anything* shouldn't make you run out of memory - unless that *anything* are bitmaps or something the like.

You can't change your physical limits, but you could change the way you work with things - if you are actually attempting to to store lots of large objects, you may want think about streaming to or from a file.

[hanst99]

new just throws if not enough memory could be allocated, that saves you a lot of checks.