Preliminary documentation for Ice for MATLAB. Do not use in production applications. Refer to the space directory for other releases.

Interfaces can be marshaled by value. For an interface marshaled by value (as opposed to a class instance derived from that interface), only the type ID of the most-derived interface is encoded. We use the following Slice definitions in our discussion:

Slice
interface Base { /* ... */ }

interface Derived extends Base { /* ... */ }

interface Example
{
    void doSomething(Base b);
}

We assume that the client passes a class instance to doSomething that does not have a Slice definition (but implements Derived).

Interface Encoding version 1.0

The on-the-wire representation of the interface parameter using encoding version 1.0 is as follows:

Marshaled Value

Size in Bytes

Type

Byte offset

1 (identity)

4

int

0

0 (marker for class type ID)

1

bool

4

"::Derived" (class type ID)

10

string

5

4 (byte count for slice)

4

int

15

0 (marker for class type ID)

1

bool

19

"::Ice::Object" (class type ID)

14

string

20

5 (byte count for slice)

4

int

34

0 (number of dictionary entries)

1

size

38

Interface Encoding version 1.1

With encoding version 1.1, the interface parameter is encoded as if it was a class with no data members. Here is the on-the-wire representation using the sliced format:

Marshaled value

Size in bytes

Type

Byte offset

1 (instance marker)

1

size

0

17 (slice flags: string type ID, size is present)

1

byte

1

"::Derived" (type ID - assigned index 1)

10

string

2

4 (byte count for slice)

4

int

12

The compact format omits the byte count for the slice:

Marshaled value

Size in bytes

Type

Byte offset

1 (instance marker)

1

size

0

1 (slice flags: string type ID)

1

byte

1

"::Derived" (type ID - assigned index 1)

10

string

2

See Also

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