OSF DCE Application Development Guide--Core Components

Attribute Configuration Language
compiler to generate encoding or decoding stubs for operations defined in a
corresponding IDL interface rather than generating RPC stubs for those operations.
The encode and decode attributes have the following syntax. (See the example at the
end of this section.)
For an interface—
[encode] | [decode] | [encode,decode] interface interface_name
For an operation—
[encode] | [decode] | [encode,decode] operation_name ([parameter_list]);
When used as an ACF interface attribute, the encode and decode attributes apply to all
operations defined in the corresponding IDL file. When used as an ACF operation
attribute, encode and decode apply only to the operation you specify. If you apply the
encode or decode attribute to an ACF interface or operation, you must not use the
auto_handle or the implicit_handle ACF attributes.
When you apply the encode or decode attribute to an operation, the IDL compiler
generates IDL encoding services stubs that support encoding or decoding, depending on
the attribute used, in the client stub code; it does not generate stub code for the operation
in the server stub. To generate an IDL encoding services stub that supports both
encoding and decoding, apply both attributes to the operation.
If you apply the encode or decode attribute to all of the operations in an interface, no
server stub is generated. If you apply the encode and decode attributes to some, but not
all, of the operations in an interface, the stubs for the operations that do not have the
encode and decode attributes applied to them are generated as RPC stubs into the server
stub module.
When data encoding takes place, only the operation’s in parameters provide data for the
encoding. When data decoding takes place, the decoded data is delivered only to the
operation’s out parameters.
If data is being both encoded and decoded, you generally declare all of the operation’s
parameters to be in,out. However, you can encode data by using the in parameters of
one operation, and decode it by using the out parameters of another operation if the
types and order of the in and out parameters are the same. For equivalence, the IDL
encoding services treat a function result as an out parameter that appears after all other
out parameters.
In the following example, the IDL compiler generates IDL encoding services stub code
for the in_array_op1, out_array_op1, and array_op2 operations, but not for the
array_op3 operation. The stub code generated for the in_array_op1 operation supports
encoding, the stub code generated for the out_array_op1 operation supports decoding,
and the stub code generated for the array_op2 operation supports both encoding and
decoding. The stub code generated for the array_op3 is an RPC client stub. For further
information on using the IDL encoding services, see Chapter 16 of this guide and the
reference pages for the idl_es_*(3rpc) routines.
Example Using the encode and decode Attributes
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