Question

I am getting access violation error in the below code..i have pointed it out in the program.

void *pBuff = 0;

void set_data(void *pBuff)
{
    int value = 70, i;
    int *phy_bn = new int[8];

    for(i=0; i<8; i++)phy_bn[i] = value;

    pBuff =phy_bn;
    cout<<((int*)pBuff)[0];//..accessing 0th element value..no error here..gives 70 as result..
}


int main()
{
    set_data(pBuff);
    cout<<((int*)pBuff)[0];//acces violation error
    return 0;
}

Why that access violation even when i am not assigning it the address of a local variable…

Yes i can use vector or pass by reference.

But i want to know why pBuff is not getting assigned

Answer 1

When you say

pBuff = phy_bn;

You’re just changing the local value of pBuff, not the global value of pBuff. Either pass pBuff as a double pointer, or simply remove the argument to the function, as pBuff is global already.

void *pBuff = 0; /* This is the global pBuff, which isn't being changed */

void set_data(void *pBuff /* This is the local pBuff, which is being changed */)
{
    ...
    pBuff = phy_bn;
    ...
}