NET/MASTER Network Control Language (NCL) Programmer's Guide

Development Considerations for System-Level NCL Procedures
Developing System-Level NCL Procedures
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An NCL Process Can Obtain Information About a Message
An NCL process can obtain information about the structure and attributes of a
message, using the EMSREAD, INTREAD, LOGREAD, and MSGREAD verbs to read a
message. (The INTREAD verb is discussed in Section 16, “Environments and
Command Processing.”) These verbs create MDO variables, called message profile
variables, that reflect the structure of the message and contain the attributes of the
message.
After reading a message, the NCL process can then obtain information about the
message by interrogating the message profile variable that contains the message data.
All NCL core statements, verbs, and built-in functions are available to analyze a
message. In particular, the ASSIGN verb allows you to obtain information about the
structure of an MDO variable and the map(s) that are used to interpret the variable.
See Section 10, “Working With Mapping Services,” and refer to the NonStop
NET/MASTER NCL Reference Manual for more information on the ASSIGN verb.
Verbs Used by System-
Level NCL Procedures
Table 17-2 summarizes the verbs used by system-level NCL procedures to read and
process system-level message flows. It shows the function of the verbs and the NCL
procedures in which each verb can be used.
Table 17-2. Verbs Used by System-Level NCL Procedures
System-Level NCL Procedure Used in
Verb Function EMSPROC LOGPROC MSGPROC
Reading message EMSREAD LOGREAD MSGREAD
Forwarding message EMSCONT LOGCONT MSGCONT
Deleting message EMSDEL LOGDEL MSGDEL
Reading a System-Level Message
You can use the EMSREAD, LOGREAD, and MSGREAD verbs in a system-level NCL
process to read a message.
When one of these verbs reads a message, it automatically places the text and the
attributes of the message into an MDO variable. The name of the MDO variable that
contains the message data depends on the name of the verb that reads the message.
This is summarized in the following table:
Verb MDO Variable Example Containing Base Color Attribute
EMSREAD &$EMS. &$EMS.MSGATTR.DISPLAY.COLOR
LOGREAD &$LOG. &$LOG.MSGATTR.DISPLAY.COLOR
MSGREAD &$MSG. &$MSG.MSGATTR.DISPLAY.COLOR
The MDO variables listed in the preceding table are automatically created by the
EMSREAD, LOGREAD, and MSGREAD verbs when they read a message. You do not
have to create these variables using the ASSIGN verb before reading a message. See