Protocol: How should I deal with variable-length array? about ddns HOT 8 CLOSED

 *     WKS RDATA format:
 *
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *     |                    ADDRESS                    |
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *     |       PROTOCOL        |                       |
 *     +--+--+--+--+--+--+--+--+                       |
 *     |                                               |
 *     /                   <BIT MAP>                   /
 *     /                                               /
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 * 
 * where:
 * 
 * ADDRESS         An 32 bit Internet address
 * 
 * PROTOCOL        An 8 bit IP protocol number
 * 
 * <BIT MAP>       A variable length bit map.  The bit map must be a
 *                 multiple of 8 bits long.

/**
 * 3.3.11. Name Server (NS) RR
 * 
 * An NS RR marks the beginning of a DNS zone and supplies the domain name of a name server for that zone. It is typically seen in two places - at the top of a zone, just after the SOA; and at the start of a subzone, where an NS (and often a paired A) are all that is required to perform delegation. See RFC 1035 §3.3.11 for a more detailed description of the NS RR.
 * 
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *     /                   NSDNAME                     /
 *     /                                               /
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 * 
 * where: 
 * 
 * NSDNAME         A <domain-name> which specifies a host which should be
 *                 authoritative
 */
 typedef char NN_t[NAME_LIMIT];

void print(int*(*a)[2],int sz2) 
{
      for (int i=0;i<2;i++) {
          for (int j=0;j<sz2;j++) printf("%d ",(*a)[i][j]);
          printf("\n");
      }
}
int main(void)
{
      int a[2][3]={1,2,3,4,5,6},b[1][3]={1,2,3};
      int c[2][2]={1,2,3,4};
      int *aa[2]={a[0],a[1]},*bb[1]={b[0]};
      int *cc[2]={c[0],c[1]};
      
      print(&aa,3); // ok
      print(&bb,3); // no
      print(&cc,2); // ok
      return 0;
}

void print(int (*a)[3],int sz1)
{
    for (int i=0;i<sz1;i++) {
        for (int j=0;j<3;j++) printf("%d ",a[i][j]);
        printf("\n");
    }
}
int main(void)
{
    int a[2][3]={1,2,3,4,5,6},b[1][3]={1,2,3};
    int c[2][2]={1,2,3,4};
    print(a,2);// ok
    print(b,1); // ok
    print(c,2); // no
    return 0;
}

void print(int** a,int sz1,int sz2)
{
    for (int i=0;i<sz1;i++) {
        for (int j=0;j<sz2;j++) printf("%d ",a[i][j]);
        printf("\n");
    }
}

int main(void)
{
    int a[2][3]={1,2,3,4,5,6},b[1][3]={1,2,3};
    int c[2][2]={1,2,3,4};
    int *aa[2]={a[0],a[1]},*bb[1]={b[0]};
    int *cc[2]={c[0],c[1]};
    print(aa,2,3);// ok
    print(bb,1,3);// ok
    print(cc,2,2);// ok
    return 0;
}

void print(void* a,int sz1,int sz2)
{
    for (int i=0;i<sz1;i++) {
        for (int j=0;j<sz2;j++) {
            int* aij=(int*)((char*)a+i*sz2*sizeof(int)+j*sizeof(int)); // int* aij=(int*)a+i*sz2+j;
            printf("%d ",*aij);
        }
        printf("\n");
    }
}
int main(void)
{
    int a[2][3]={1,2,3,4,5,6},b[1][3]={1,2,3};
    int c[2][2]={1,2,3,4};
    print(a,2,3); // ok; or, print(&a,2,3);
    print(b,1,3);// ok
    print(c,2,2);// ok
    return 0;
}

typedef struct _test {
    int     num;
    int**   arr;
    char    data[0];
}test;

test* t = (test *) malloc(sizeof(test) + 10);

t->data[0] = 'h';
t->data[1] = 'e';
 ...

printf("check the data[0] = %c", t->data[0]);