Guardian Programmer's Guide

Using the File System
Guardian Programmer’s Guide — 421922-014
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Process File Names
The device-name part of the name can be up to 8 characters long and must start
with a dollar sign ($). Again, all characters must be alphanumeric, and the second
character of the device-name part must be a letter. The qualifier is an optional
alphanumeric string that always begins with the pound sign (#) character followed by
an alphabetic character. The meaning of a qualifier depends on the device type.
We recommend using device names to identify devices. However, you can also
identify a device using a logical device number that is an integer always preceded by a
dollar sign. Five digits (up to 34492) are allowed in the logical device number.
Process File Names
Process file names have two forms: one for named processes and one for unnamed
processes.
Process File Names for Named Processes
You can name a process at the same time you create the process either by specifying
the NAME option of the RUN command or by specifying the name-option parameter
when calling the PROCESS_CREATE_ procedure. You can accomplish the same
thing with the PROCESS_LAUNCH_ procedure, although the equivalent parameters
are passed as fields in a structure. Process creation is described in detail in
Section 16, Creating and Managing Processes.
Assigning a name to a process hides its location in the operating system and hides
whether it can reference a process pair. A process name also makes interprocess
communication easier, because the name that you pass to the FILE_OPEN_
procedure is already known. On the other hand, a process that wants to communicate
with an unnamed process cannot have prior knowledge of the process file name; it
must establish what the process file name is at run time, then pass it to the
FILE_OPEN_ call.
The syntax for file names for named processes follows:
A named process is identified by an alphanumeric name in the process-name field.
A process-name is made up of 1 to 5 alphanumeric characters beginning with a
dollar sign ($). The character after the dollar sign must be a letter.
The optional sequence number (seq-no) enables instances of a process name to be
distinguished over time. A specific process name often represents a service (for
example, $S is a spooler collector), and the user does not care whether the service
provider is the same instance as it was some time earlier; the user simply wants the
service. The seq-no field is therefore often omitted. However, although failure and
restart of a server is irrelevant to some requesters, it may be important to others. The
Process file name, named process:
[node-name.]process-name[:seq-no][.q1[.q2]]