OSF DCE Application Development Guide--Introduction and Style Guide

Introduction to DCE Application Programming

1.5.5.2 Telling RPC Runtime What Protocol Sequences to Use

The second thing registering the server does is it obtains a set of endpoints and associates

them with the desired protocol sequences. Endpoints are the host’s address numbers on

which the server can receive incoming calls. This begins the process of actually setting

up the information that the server’s clients will need in order to bind to it.

The endpoints are usually dynamically generated each time the server starts. However,

some applications may use well-known endpoints that are the same every time the server

starts. If well-known endpoints are used, they are typically deﬁned in the interface

deﬁnition with the endpoint attribute.

In the default case, all valid protocol sequences are used when the

dce_server_register( ) routine is called. The dce_server_c_no_protseq ﬂag can be

passed in the ﬁrst argument to the routine in cases where dynamic assignment of

endpoints is not desired; for example, when well-known endpoints (speciﬁed in the IDL

deﬁnition) are being used.

1.5.5.3 Registering the Binding Information with the Endpoint Mapper Service

After server registration obtains the endpoints, the endpoints, protocol sequences, and

object UUIDs are registered with the endpoint mapper service of the local host’s dced.

Typically the server has received a certain number of endpoints dynamically allocated on

its host machine. However, when prospective clients import binding information from

the namespace, they get partial bindings. When they ﬁrst try to contact their server, the

partial binding will get them only as far as the server’s endpoint mapper service. The

purpose of registering endpoints is to let the endpoint mapper know what endpoints

belong to the server so that it can ﬁll in the partial bindings as they arrive and route the

incoming remote calls on their proper ways. Subsequent remote calls executed with the

same bindings will go straight to the server, since the bindings are now complete.

The purpose of registering endpoints together with object UUIDs is to account for all

possible incoming object UUIDs (that is, object UUIDs that could appear in incoming

partial bindings arriving at the endpoint mapper), and to associate with each of them one

of the server’s allocated endpoints. Then the endpoint mapper can simply look up the

object UUID, ﬁnd an endpoint, insert it into the binding, and send the RPC on to its

destination.

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