Using empty arrays for passing of variable structures as arguments

[Bogdan Lotko]

Hello,

Is it a good idea to use arrays for controlling the variable content of 
a structure ( normally it would be a pointer that could be NULL) by passing
it as parameter?

e.g.

typedef strruct
{
    int x;
    int y;
} structB;

struct A
{
   bool       hasB; // just as example
   structB *sB;     // Must not be NULL if hasB == true
...
}

The sent type will be always coded as (ba(ii)) where the array can have 
0 or 1 entries.

If the structB is empty ("sB == NULL") the empty array will be sent.
The coding in low level API would be like:

// Structure container strA for struct A already opened

dbus_message_iter_open_container( &str,
                                                                    
DBUS_TYPE_ARRAY,
                                                                    (ii),
&arr );
// if "not NULL" open and fill the strB container for struct B
// otherwise close the arr container immediately

dbus_message_iter_open_container( &strA, &arr );

Is there any other / better  method do this same?

Thanks for your help

with best regards,

Bogdan