memory allocation in c

It can be done, but doing it is a bad idea. Such design of code is error-prone and not supportable. Also, there are no situations when it helps.

[EDIT]

I recommend limiting allocation and deallocation of the same variable by the same stack frame. In between, the pointers can be passes to any other function, but deallocation should be done only when all the executions returns where it was allocated.

Another layout for the allocating and deallocating code should be this: allocation in a constructor and deallocation in a destructor. As this is C, I did not mention it in first place, but even in C one can introduce regular functions logically playing the role of constructor and destructor.

(In a sense, even fully-fledged OOP is quite possible in plain C and even in Assembly Language. On way of doing it is to introduce explicit notion of vtable and pass "this" explicitly as a regular by-pointer function parameter. Automatic covariance and contravariance would be pretty hard to achieve though.:-))

Please see my argument with Espen below.

—SA

As RHuros states you should use malloc and free.

If I'm right and you want to do that across different functions you should take a look at this code:

#include "stdafx.h"
#include "stdlib.h"
#include "conio.h"

void reserve(void* &pchar)
{
    pchar = malloc(10000);
    printf("malloc ==> ");
}

void remove(void* &pchar)
{
    free(pchar);
    printf("free.\n");
}

int _tmain(int argc, _TCHAR* argv[])
{
    void* pchar = NULL;

    while (!_kbhit())
    {
        reserve(pchar);
        remove(pchar);
    }
    return 0;
}

NOTE:
Keep in mind that this is not a good design... you should not do that as it would be hard to maintain in the future. It can be done and it will work anywhere, but it should not be done to avoid possible problems.

Hope this helps... :thumbsup: