Portability Issues

Chapter 1: Introduction

The UNIX Option enables you to off-load application development from a UNIX system to NetExpress. This means that you can create applications on a PC, using the tools provided by NetExpress, and then deploy them, when ready, on a UNIX system that has a version of Micro Focus COBOL for UNIX installed.

Note: To use the UNIX Option you need to install some software, and to change some configuration files, on the UNIX system. To do this, you need to have superuser access to your UNIX system, and to possess the relevant skills to configure your UNIX system. In particular, you need to know how to:

If you are not familiar with these tasks, ask your UNIX system administrator.

You should also be familiar with the effects of using DNS on UNIX systems, and basic network problems. If you are not, then ask your UNIX system administrator.

The UNIX Option comprises:

• Publisher - copies applications to the UNIX system, and controls the build process on the UNIX system. A set-up utility for Publisher enables you to control the deployment process. For example, you can specify which UNIX system to deploy to, the directory to which applications are copied, the directory to use for copyfiles, and so on.

  See the chapter Publishing Applications for details on using Publisher. See the chapter Publisher Set-up for details on configuring Publisher.
  
  

• An import wizard that enables you to import an Object COBOL for UNIX application into NetExpress. See the chapter Importing UNIX Applications into NetExpress for details.
  
  
• Character Dialog System V2.5 - enables you to create character interfaces for your UNIX applications. Character Dialog System has its own on-line book, Character Mode User Guide (dcpubb07.htm).
  
  
• PowerTerm - provides terminal emulation on your PC so that you can connect with your UNIX system from NetExpress. PowerTerm is documented in its own Help.
  
  
• Samba - provides remote drive access to your UNIX system using standard Windows networking.

Some syntax that you can use in NetExpress COBOL is incompatible with COBOL for UNIX. If you compile on NetExpress a program with the WARNINGS(2) Compiler directive set, the Compiler displays warning messages if it finds incompatible syntax. However, it is not possible for the Compiler to flag all incompatibilities; you will have to check for some of these yourself. The chapter Portability Issues lists the syntax that the Compiler can flag as incompatible, and describes syntax incompatibilities for which you should check.

1.1 Overview of Publishing Applications

The process of deploying and rebuilding an application on a UNIX system is called "publishing". The UNIX Option provides a tool, Publisher, that handles the publishing process.

Note: You cannot publish to a UNIX system applications that have been generated on NetExpress using the Data Access Wizard.

The development process for creating a deployable application is:

1. Create and develop an application using the NetExpress tools.
   
   
2. Set the WARNING"2" Compiler directive. Compile the application. Syntax incompatible with COBOL for UNIX is flagged. Change the syntax as required. Check the chapter Portability Issues for details of any other syntax that might cause problems to COBOL for UNIX. Recompile as necessary.
   
   
3. When you have an application that builds without errors:
   
   
   1. Set up Publisher for this project. See the chapter Publisher Set-up for details. You normally only need to do this once for the project.
      
      
   2. Publish the application. For details see the chapter Publishing Applications.
      
      
4. Run the application on the UNIX system. If run-time errors occur, fix them using NetExpress, rebuild the application, and republish.

If you want to use NetExpress to edit and rebuild a COBOL application that already exists on a UNIX system, you will need to import the application into NetExpress. The chapter Importing UNIX Applications into NetExpress describes how to do this.

1.2 The Server Control Program

The Server Control Program (SCP) provides a standardized set of facilities that enable communication between NetExpress and the UNIX system. It must be installed on the UNIX system before any you can publish an application. See the appendix Installing SCP and Samba for information on installing SCP.

1.3 PowerTerm

PowerTerm is supplied with the UNIX Option so that you can start a terminal (Telnet) connection from your PC to your UNIX system. This enables you to:

• Test your deployed application from the PC
  
  
• Use COBOL for UNIX tools on the remote system, such as the Editor or Animator, from your PC

Because PowerTerm enables you to use COBOL tools on the remote system, the button-bar at the bottom of the PowerTerm window has been changed from its standard settings. The button-bar is set by the UNIX Option so that the buttons are F1 to F10, plus /A (Alt) and /C (Ctrl). The buttons have been set this way as the tools provided with Toolbox (in COBOL V3.2 and V4.0 for UNIX) or the Development Environment Menu System (Object COBOL V4.1 and Server Express) use the F1 to F10 function keys, and the Alt and Ctrl keys to navigate through their menu systems. By setting the button-bar in this way, you can use the mouse to click buttons on the button-bar to move around the menus of COBOL tools.

PowerTerm is also configured by the UNIX Option to have a default terminal emulation of SCO-ANSI (this terminfo is supplied with the COBOL for UNIX product), and thus the display is set to 25 lines, instead of the default of 24, to match the COBOL tools.

If you need to set the button-bar to emulate other key presses or hot keys, or want to reset the number of lines displayed, see the PowerTerm help.

1.4 Case Sensitivity

The case of literals - particularly filenames - can cause problems when publishing applications to a UNIX system. In general, the PC ignores the case of a filename so that, for example, filename1 is equivalent to FILENAME1 or FiLeName1; on UNIX systems filename1 would be regarded as a filename distinct from FILENAME1. As a consequence of this:

• The NetExpress development environment can map filenames to upper case (for user readability) or display them in the filesystem's case, but does not guarantee that their case is preserved when the application is built.
  
  
• Programs created on a PC might mix the case used in CALL and COPY statements. While this does not matter on the PC, it is important on a UNIX system.
  
  
• PC-based fileservers that use older Microsoft and Novell protocols ignore the case of filenames. Newer fileservers (for example, Windows NT Server or Novell V4) do, however, support mixed case.
  
  

For example, say you create a program called myapp.cbl. Depending on the application and the operating system you used to save the program, or the network protocol you are using to connect to your UNIX system, the real filename might be, for example, myapp.cbl (Windows NT), Myapp.cbl (Windows 95) or MYAPP.CBL (on some versions of Novell). Windows regards all these versions of the filename as the same, but to UNIX they are all different. So, if you create a program that contains the code call myapp.cbl, the call will work as expected on Windows, but cause problems on the UNIX system as the filename of the published program might be myapp.cbl, or Myapp.cbl.

To overcome these problems, you can configure the Publisher to handle filenames in particular ways. For information see the chapter Publisher Set-up.

1.5 Character Dialog System

A character version of Dialog System is installed with the UNIX Option to enable you to develop applications for deployment on UNIX. When creating an application using character Dialog System, you must ensure it picks up the correct versions of certain files, and not the versions from regular Dialog System. To ensure this, copy the files ds-cntrl.mf and ds-cntrl.ans from c:\NetExpress\Unix\Dschar\Source into your application's project directory. You must do this before creating the project.

Portability Issues