OSF DCE Application Development Guide--Core Components

OSF DCE Application Development Guide—Core Components

The component name that you specify at the top of a sams ﬁle must consist of a three-

character (no more, no less) string. For the ‘‘Hello World’’ program, we will use the

component name hel:

# Part I of simple sams file ...

component hel

The hel string will be used to identify all the ﬁles and data structures that sams will

generate from the ﬁle.

The second part of the sams ﬁle contains some additional serviceability-speciﬁc

information about the message data structures that will be generated. (This information is

necessary if the sams ﬁle is intended for serviceability use because sams is also used to

generate message ﬁles for general, nonserviceability use.)

This part of the ﬁle speciﬁes the names of the serviceability table and the serviceability

handle. It also contains a list of the component’s subcomponents. A subcomponent

consists of a distinct functional module of executing code. For example, most distributed

applications would have a basic server subcomponent, a reference monitor

subcomponent that would handle authorization decisions, and one or more

subcomponents that would contain the application’s particular functionality.

The serviceability interface ﬁnds a component’s messages in one or more subtables, each

one associated with a subcomponent. When the message is displayed or written, the

associated subcomponent name is written in a ﬁeld of the message. This allows

messages to be distinguished during routing or other processing on the basis of the

subcomponent with which they are associated.

Following is what the second part of our simpliﬁed sample sams ﬁle looks like. We call

the serviceability table hel_svc_table, and we call the serviceability handle

hel_svc_handle. Although we have used the three-letter component code hel in these

names, we were under no obligation to do so; we could have named the table and the

handle anything we wanted. (We will need to know both of these names when we make

the call in the application to initialize the interface in preparation for displaying

messages.)

A component must have at least one subcomponent speciﬁed in its sams ﬁle.

Subcomponents are speciﬁed in this part simply by supplying their table index, their

name, and their descriptive id in a series of separate lines, one per subcomponent and

each one beginning with the sub-component keyword, between a set of start and end

keywords:

# Part II

serviceability table hel_svc_table handle hel_svc_handle

start

subcomponent hel_s_main "main" hel_i_svc_main

end

In our example,

hel_s_main is the table index name for the subcomponent. Serviceability

routines need this name in order to locate and print any of the

subcomponent’s messages.

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