OSF DCE Application Development Guide--Core Components

Interface Definition Language
version (1.1) /* major and minor version numbers */
version (3) /* major version number only */
The version attribute can be omitted altogether, in which case the interface is assigned
0.0 as the default version number.
A client and a server can communicate only if the following requirements are met:
• The interface imported by the client and the interface exported by the server have the
same major version number.
• The interface imported by the client has a minor version number less than or equal to
that of the interface exported by the server.
You must increase either the minor version number or the major version number when
you make any compatible change to an interface definition. You must not decrease the
minor version number unless you simultaneously increase the major version number.
You must increase the major version number when you make any incompatible change to
an interface definition. (See the definition of compatible changes that follows.) You
cannot decrease the major version number.
The following are considered compatible changes to an interface definition:
• Adding operations to the interface, if and only if the new operations are declared
after all existing operation declarations in the interface definition.
• Adding type and constant declarations, if the new types and constants are used only
by operations added at the same time or later. Existing operation declarations cannot
have their signatures modified.
The major and minor integers in the version attribute can range from 0 to 65,535,
inclusive. However, these typically are small integers and are increased in increments of
one.
The following are considered incompatible changes to an interface definition:
• Changing the signature of an existing operation
• Changing the order of existing operations
• Adding a new operation other than at the end
The version attribute can appear at most once in an interface.
17.7.3 The endpoint Attribute
The endpoint attribute specifies the well-known endpoint or endpoints on which servers
that export the interface will listen. The endpoint attribute takes the following form:
endpoint (endpoint_spec, ... )
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