transmit_as

typedef [transmit_as(xmit-type) [ , type-attribute-list ] ]
    type-specifier declarator-list;

void __RPC_USER type-id_to_xmit (
    type-id __RPC_FAR *,
    xmit-type __RPC_FAR * __RPC_FAR *);

void __RPC_USER type-id_from_xmit (
    xmit-type __RPC_FAR *,
    type-id __RPC_FAR *);

void __RPC_USER type-id_free_inst (
    type-id __RPC_FAR *);

void __RPC_USER type-id_free_xmit (
    xmit-type__RPC_FAR *);

xmit-type

Specifies the data type that is transmitted between client and server.

type-attribute-list

Specifies one or more attributes that apply to the type. Valid type attributes include handle, switch_type; the pointer attribute ref, unique, or ptr; and the usage attributes string and ignore. Separate multiple attributes with commas.

type-specifier

Specifies a base_type, struct, union, enum type, or type identifier. An optional storage specification can precede type-specifier.

declarator-list

Specifies standard C declarators, such as identifiers, pointer declarators, and array declarators. For more information, see pointersH20NZW and arrays1EV5ZM5. The declarator-list consists of one or more declarators separated by commas. The parameter declarator in the function declarator, such as the parameter name, is optional.

type-id

Specifies the name of the data type that is presented to the client and server applications.

Examples

typedef struct _TREE_NODE_TYPE { 

    unsigned short data;

    struct _TREE_NODE_TYPE * left;

    struct _TREE_NODE_TYPE * right;

} TREE_NODE_TYPE;

typedef [transmit_as(TREE_XMIT_TYPE)] TREE_NODE_TYPE * TREE_TYPE;

void __RPC_USER TREE_TYPE_to_xmit(

    TREE_TYPE __RPC_FAR * ,

    TREE_XMIT_TYPE __RPC_FAR * __RPC_FAR *);

void __RPC_USER TREE_TYPE_from_xmit (

    TREE_XMIT_TYPE __RPC_FAR *,

    TREE_TYPE __RPC_FAR *);

void __RPC_USER TREE_TYPE_free_inst(

    TREE_TYPE __RPC_FAR *);

void __RPC_USER TREE_TYPE_free_xmit(

    TREE_XMIT_TYPE __RPC_FAR *);

Remarks

The transmit_as attribute instructs the compiler to associate type-id, a presented type that client and server applications manipulate, with a transmitted type xmit-type. The user must supply routines that convert data between the presented and the transmitted types; these routines must also free memory used to hold the converted data. The transmit_as attribute instructs the stubs to call the user-supplied conversion routines.

The transmitted type xmit-type must resolve to a MIDL base type, predefined type, or a type identifier. For more information, see base_types3M9G8ZP.

The user must supply the following routines:

The client stub calls type-id_to_xmit to allocate space for the transmitted type and to translate the data into objects of type xmit-type. The server stub allocates space for the original data type and calls type-id_from_xmit to translate the data from its transmitted type to the presented type.

Upon return from the application code, the server stub calls type-id_free_inst to deallocate the storage for type-id on the server side. The client stub calls type-id_free_xmit to deallocate the xmit-type storage on the client side.

The following types cannot have a transmit_as attribute:

    Context handles (types with the context_handle type attribute and types that are used as parameters with the context_handle attribute)

    Parameters that are conformant, varying, or open arrays

    Structures that contain conformant arrays

    The predefined type handle_t, void

When a pointer attribute appears as one of the type attributes with the transmit_as attribute, the pointer attribute is applied to the xmit_type parameter of the type-id-to_xmit and type-id-from_xmit routines.

See Also