I found binary packing issue that cannot get last binay length.
in folloing code:

~~~

include <stdio.h>

include <stdlib.h>

include <string.h>

include <assert.h>

include <wiredtiger.h>

int main(void)
{
WT_CONNECTION *conn;
WT_SESSION *session;
int i, rc;
unsigned char buf[32];
WT_ITEM items[] = {

{"a", 2}

,

{"bb", 3}

,

{"ccc", 4}

,
};
WT_ITEM a, b, c;

memset(buf, 0xff, sizeof(buf));

rc = wiredtiger_open("data", NULL, "create", &conn);
assert(rc == 0);
rc = conn->open_session(conn, NULL, NULL, &session);
assert(rc == 0);

rc = wiredtiger_struct_pack(session, buf, sizeof(buf),
"uuu", &items[0], &items[1], &items[2]);
assert(rc == 0);

printf("Packed: ");
for(i=0;i<sizeof(buf);i++)

{ printf("%02x", buf[i]); }

printf("\n");

rc = wiredtiger_struct_unpack(session, buf, sizeof(buf),
"uuu", &a, &b, &c);
assert(rc == 0);
printf("a: size=%ld, data=%s\n", a.size, a.data);
printf("b: size=%ld: data=%s\n", b.size, b.data);
printf("c: size=%ld, data=%s\n", c.size, c.data);

rc = conn->close(conn, NULL);
assert(rc == 0);
return 0;
}
~~~

We can not third binary length.
unpack result:
~~~
Packed: 8261008362620063636300ffffffffffffffffffffffffffffffffffffffffff
a: size=2, data=a
b: size=3: data=bb
c: size=25, data=ccc
~~~

Actually what I want to do is packing variable length array.
I will ask next question, if this issue become clear.

Thank you.