What this Chapter is About

This chapter describes the use of the TUXEDO System/T /Workstation under the OS/2 operating system

This instantiation offers significant benefits to application developers:

• More memory is available to OS/2 applications, as compared to MS-DOS applications which normally cannot access memory above 640K.
• Executable text is shared among applications, saving memory.
• /Workstation upgrades are possible without relinking or modifying an application program's executable file.
• Dynamic linking permits interpretive graphical application generator tools (such as ObjectVision) to call TUXEDO System/T services.

The major sections in this chapter cover:

• software prerequisites
• System/T client programs and the OS/2 environments.

Definitions of Terms, Acronyms and Abbreviations

System/T terms are defined in the BEA TUXEDO Glossary but we have extracted terms specific to this feature:

Dynamic Link Libraries (DLL)

A DLL is a collection of functions grouped into a load module that is dynamically linked with an executable program at run time. It is similar to a shared object under the UNIX operating system. The IBM OS/2 operating environment makes extensive use of this feature. Most software products for OS/2 provide a DLL interface.

Ordinal Export Numbers

An ordinal export number is a number assigned in a module definition file, by which a function in a DLL may be referenced. Some software packages reference DLL functions by name, while others (for example, SQLWindows) reference DLL function entry points by numbers.

Import libraries

An import library is a collection of stub function names associated with a DLL. To link edit an application object calling a DLL routine, the linker needs a stub that defines where the subroutine exists.

OS/2 Character Mode

OS/2 Character mode is the character-based non-graphical user interface under OS/2.

Module Definition File

This file defines the characteristics of an executable and is used at link time. For a DLL this file details the exported functions that can be called from the DLL and other imported functions which the DLL will call.

Windows Emulation Mode

It is possible for OS/2 version 2.0 to execute Windows applications, which in turn could call System/T's Windows DLL. LAN WorkPlace for OS/2 permits System/T's Windows DLL to execute in this environment.

Prerequisites

Hardware

The /Workstation DLL for OS/2 runs on Intel 80386 and above processors.

The machine on which the DLL is installed runs as a remote machine to a TUXEDO machine.

Software

The OS/2 DLL runs under the IBM OS/2 2.0 operating system for OS/2 character mode applications.

BEA TUXEDO provides a 32-bit DLL for OS/2 that supports the OS/2 2.x version of the operating system. The networking software for this version is IBM TCP/IP. For developing applications and 32 bit compiler can be used. The DLL was compiled using the IBM Cset 2 C++ compiler, which is also the reference compiler.

The TUXEDO server machine must have the TUXEDO System/T Release 4.2 (or higher) and the /Workstation installed.

Programming Considerations with OS/2 Clients

This section covers items specific to writing and building TUXEDO System/T client programs to run under OS/2. They are intended to supplement the material presented in the BEA TUXEDO Programmer's Guide.

Writing Client Programs

The ATMI and FML calls used in OS/2 client programs are much the same as described in the BEA TUXEDO Programmer's Guide. They must, however, be incorporated into OS/2 modules. The following things work slightly differently than they do in the UNIX environment.

Global Variables

The error global variables are not available in the way they normally are; they are defined as macros in the .h files. To make them available in client programs:

for tperrno or tpurcode -- #include "atmi.h"
for Ferror -- #include "fml.h"
for Uunixerr -- #include "Uunix.h"
for proc_name -- #include "userlog.h"

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