HP NonStop G-Series - Manual (Page 79)

5 The Tandem DDE Gateway
Bridge Program
110838 Tandem Computers Incorporated 5–1
You use the Tandem DDE Gateway Bridge program to create a Tandem DDE Gateway
Dictionary that is used when your client application communicates with the Tandem
DDE Gateway using the element-by-element approach. The Tandem DDE Gateway
Dictionary assists with automatic data conversion and ensures that data is placed at
the correct byte offset in the message buffers within the Tandem DDE Gateway.
Follow these steps to create a Tandem DDE Gateway Dictionary on your workstation:
1. Define your application servers’ message layouts using Tandem Data Definition
Language (DDL).
2. Prepare your DDL source by adding special directives used by the Bridge. These
directives identify, among other things, which structures in your DDL are
messages (as opposed to file record layouts, data type definitions, and so on).
3. Compile your DDL source using the Tandem DDL compiler.
4. Run the Tandem DDE Gateway Bridge program.
5. As an option, merge the dictionary file output by the Bridge program with other
dictionary files created with the Bridge program from other Tandem DDL
dictionaries.
6. Sort the resulting file using the Tandem FastSort program.
7. Stop the Tandem DDE Gateway on your workstation.
8. Download the sorted dictionary file to your workstation. You can download using
the Tandem Information Exchange Facility (IXF) or by using a Tandem file server
such as the Multilan file server. If you use IXF, specify the BINARY option.
9. Update the Tandem DDE Gateway configuration file (DdeDict option) to reference
your downloaded dictionary.
10. Restart the Tandem DDE Gateway on your workstation.
Preparing Your Data
Definition Language
(DDL) Source
The Bridge program uses directives you enter into your DDL source as DDL
comments by entering lines that start with an asterisk (*) character. The Bridge
program can read the DDL comments only from the DDL dictionary. DDL comments
are stored in the DDL dictionary only if you specify the DDL ?COMMENTS directive
to the DDL compiler. You should not need to change any existing DDL definitions to
successfully use the Tandem DDE Gateway. You can use the following Bridge
directives:
TDMGW-IPC
to identify a DDL structure as a message structure.
TDMGW-C-STRINGS
to identify a message structure for which the Tandem DDE Gateway automatic
data conversion should terminate alphanumeric data element values with a byte of
binary zeros.
TDMGW-DDEALIAS
to provide an abbreviated name for a data element. The size limit in the Tandem