Why nested structure member get alter despite const qualifier declaration?

Question

I observed nested structure member get alter despite my const qualifier declaration, may I know any method for me to avoid nested structure member get alter inside the function?

Code

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

struct middle_data
{
    struct base_data *int_data_ptr;
};

struct base_data
{
    int value;
};

void function( const struct  middle_data const *middle_ptr)
{

    middle_ptr->int_data_ptr->value= 2; // how to forbid value get alter?

    struct base_data *ptr= middle_ptr->int_data_ptr;

    printf("ptr->value = %d\n",  ptr->value);
}

int main(int argc, char **argv)
{

   struct  middle_data *middle_data_ptr;

    middle_data_ptr = (struct  middle_data*)malloc(sizeof(*(middle_data_ptr)));

    middle_data_ptr->int_data_ptr =malloc(sizeof(*(middle_data_ptr->int_data_ptr)));

    middle_data_ptr->int_data_ptr->value=3;

    function(middle_data_ptr);

    printf("  middle_data_ptr->int_data_ptr->value = %d\n",    middle_data_ptr->int_data_ptr->value);

    free(middle_data_ptr);
    free(middle_data_ptr->int_data_ptr);
    return 0;
}

Answer 1

The only way to do this is making the member of the struct base_data as const