With the SPoD utility protocol it is possible to invoke a program on the Natural Development Server, send alphanumeric data to the server (up to a maximum of 5000 bytes) and receive alphanumeric data from the server (up to a maximum of 5000 bytes). This works similar to a Natural RPC call. The server program(s) can communicate with the client program(s), i.e. data can be exchanged with the client when the server program is still running.
Important:
The programs running on the Natural Development Server must not
perform any screen I/O operations. This would result in a break down of the
server connection.
Two APIs and two example programs are provided in library
SYSEXNDC of Natural for Windows installed on the client side.
The corresponding APIs and example programs on the server side are
provided in the library SYSEXNDV of the Natural Development
Server.
The APIs can be used together with the SPoD utility protocol.
This document covers the following topics:
For the client programs the following APIs and examples are provided in
library SYSEXNDC of Natural for Windows:
NDVC001N |
This subprogram returns the status of a connection to the remote Natural Development Server environment. It can be used to check whether it is possible to connect to a server application. |
NDVC002N |
This subprogram provides access to a connection to the remote Natural Development Server environment. It invokes a program on the server. The library and program name are part of the data sent to the server. |
NDVC001P |
This example explains how to design a
user-defined program to call subprogram NDVC001N. It also contains
a description of the parameters of subprogram NDVC001N.
|
NDVC002P |
This example explains how to design a
user-defined program to call subprogram NDVC002N. It also contains
a description of the parameters of subprogram NDVC002N.
|
On the server, the following APIs and examples are provided in the
library SYSEXNDV of the Natural Development Server. The
description of the parameters can be found in the text member
A-README in the same library.
NDVS001N |
This subprogram, which must be called when a
server program is started, is used for the initialization of the server
environment. It sets the steplibs SYSLIB and SYSLIBS
in the user steplib table and checks if the trace function is active.
|
NDVS002N |
This subprogram should be called at the end of a
server program before the END or STOP instruction for
cleanup reasons. It deletes the steplibs SYSLIB and
SYSLIBS from the user steplib table.
|
NDVS003N |
Natural subprogram that enables you to exchange data with the client program. |
NDVS004N |
Natural subprogram that enables you to write
trace data into a Natural text member or into the Natural Development Server
log file. This may be helpful during program development and for error tracing.
Note: |
A small example application that illustrates how to use the different APIs is provided with the Natural Development Server.
The client program is provided in the library SYSEXNDC of
Natural for Windows.
The server programs are provided in the library SYSEXNDV of
the Natural Development Server.
For the client side, the following program is provided:
NDVCMAIN |
This program checks whether the remote environment is active and enables you to invoke five different programs on the server side. To activate the program, create a customized user command as described in the section How to Execute a Program Locally in Natural Studio When a Remote Environment is Active. |
For the server side, the following example programs are provided:
NDVSPING |
This is an example program for the
PING function. It reads the data sent by the client program and
simply returns a filled buffer.
|
NDVSINTA |
This is an example program for the interaction handling. It reads the data sent by the client program, returns data to the client, and waits for an answer from the client. Depending on the data sent by the client, it continues sending data or stops processing. |
NDVSEMPR |
This is an example program that reads the
EMPLOYEES file and sends the data to the client. It is an
extension of the interaction handling demonstrated in
NDVSINTA.
|
NDVSTRCE |
This is an example program that enables you to switch the trace facility on or off. The above mentioned example programs all write trace data if the trace facility is activated. |
NDVSWRLG |
This is an example program that writes a message into the Natural Development Server log file. |
In order to communicate with a program on the Natural Development Server, a Natural program or dialog must be executed locally in Natural Studio when you are connected to a remote Natural Development Server environment (that is, when your current active library is a library on the Natural Development Server). This can be easily achieved by defining a customized user command in Natural Studio.
In order to execute NDVCMAIN, your customized user command
must contain the following:
LOGON SYSEXNDC; NDVCMAIN
A detailed description on how to create customized user commands is given in the Natural for Windows documentation under User Commands in the section Customizing Natural Studio of the Using Natural Studio documentation.