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

struct record {
  int id;
  struct record **friends;
};

int main(){
    int i;
    struct record *data;

/* This uncommented piece of code works as it is supposed to */
//  data=malloc(3*sizeof(struct record));
//  data[0].friends=malloc(2*sizeof(struct record));    
//  for(i=0;i<3;i++) data[i].id=i;
//  data[0].friends[0]=&data[1];
//  printf("%d %d\n", data[0].id, data[0].friends[0]->id);  

    subroutine(&data);
}

void subroutine(struct record **data){
    int i;
    
/* This piece of code produces a wrong output */
    *data=malloc(3*sizeof(struct record));
    (*data)[0].friends=malloc(2*sizeof(struct record));
    for(i=0;i<3;i++) (*data)[i].id=i;
    (*data)[0].friends[0]=data[1];
    printf("%d %d\n", (*data)[0].id, (*data)[0].friends[0]->id);  
}