#include <stdio.h>

typedef struct __attribute__((packed))
{
    int elem1;
    long long elem2;
    long elem3;
} teststruct1;

typedef struct  __attribute__((packed))
{
    char elem1;
    teststruct1 thestruct;
    char elem3;
} teststruct2;

int main()
{
    teststruct2 temp =
    {
        .elem1 = 'a',
        .thestruct =
        {
            1,3,5
        },
        .elem3 = 'b'
    };
    //for confirmation
    printf("actual size of testruct1: %d\n", sizeof(teststruct1));

    printf("calculated size of testruct: %d\n", &temp.elem3 - (&temp.elem1 + 1));
    return 0;
}