How to fix "Pointer being realloc'd was not allocated" error

Question

I have a structure called House and it includes a char array for neighborhood. I am trying to read a database of houses and create an array for the houses with the same neighborhood. Reading part is working fine but while I'm creating a new array for a neighborhood my function only enters the loop for 23 times and finds first 23 houses with the same neighborhood and gives this error.

pro(4740,0x10d06f5c0) malloc: * error for object 0x7ff724d00030: pointer being realloc'd was not allocated pro(4740,0x10d06f5c0) malloc: * set a breakpoint in malloc_error_break to debug

typedef struct house{
  int id;
  int lotarea;
  char street[5];
  int saleprice;
  char neighborhood[10];
  int yearbuilt;
  int overallqual;
  int overallcond;
  char kitchenqual[3];
} House;



House* get_neighborhoods(House house, House* array) {
printf("Get neighborhoods of house with id %d\n", house.id);

House* temp = array;
int counter = 1;


House* newarray = malloc(sizeof(House));

if (newarray == NULL) {
    printf("Malloc error...");
}


while (temp != NULL) {
    if (!strcmp(temp->neighborhood, house.neighborhood)) {


        if (counter > 1) {
            realloc(newarray, sizeof(House) * counter);
        }

        copy_house(newarray + counter - 1, temp);
        print_house(newarray[counter - 1]);
        counter++;
    }

    temp++;
}

return newarray;

}

Answer 1

You must assign the return value from realloc. You have

realloc(newarray, sizeof(House) * counter);

The second time you call it (in the loop), the pointer you previously passed to it has already been freed, but you discarded the new value.

newarray = realloc(newarray, sizeof(House) * counter);

Ideally you would assign the return value to a temporary variable, so you can check if the realloc succeeded.