TNS/R Native Application Migration Guide

TNS/R Native Application Migration Guide—523745-001

8-1

Common Run-Time Environment

(CRE) Migration Tasks

The CRE coordinates many run-time tasks on behalf of the language-specific run-time

libraries, thus providing a common environment for all routines in a program,

regardless of their languages. Most programs use CRE services implicitly by calling

language specific run-time libraries, such as the C run-time library, which in turn call

the CRE. You do not need to change TNS programs that use CRE services implicitly to

migrate them to native mode.

This section describes the changes required to migrate applications that make explicit

use of CRE services; that is, programs that make explicit calls to the CRE_, RTL_, and

CLU_ functions. TAL ‘main’ routines that run in the CRE make explicit use of CRE

services and require changes. (Most programs with a TAL ‘main’ routine do not run in

the CRE.) Topics in this section are:

•

Changing pTAL Programs to Run in the CRE

•

Specifying Header Files on page 8-2

•

Replacing Obsolete CRE Functions on page 8-2

Changing pTAL Programs to Run in the CRE

A program with a TAL main routine that runs in the CRE calls the

TAL_CRE_INITIALIZER_ procedure to initialize and establish the CRE. There is no

equivalent procedure for pTAL. Therefore, a pTAL procedure cannot be the main

procedure in a program that runs in the CRE. To migrate a program that runs in the

CRE from TAL to pTAL:

•

Delete the call to TAL_CRE_INITIALIZER_.

•

Delete the MAIN keyword from the main procedure.

•

Write a simple C ‘main’ function that calls the pTAL procedure that previously was

declared ‘main’.

The C main function automatically initializes the CRE. Because the program now has a

C main function, you must link to the shared run-time libraries (SRLs) and CRTLMAIN

module required by native C programs. See the CRE Programmer’s Guide and C/C++

Programmer’s Guide for details.

Unlike the TAL compiler, which requires an ENV COMMON or ENV NEUTRAL

directive for programs that run in the CRE, the pTAL compiler does not require any

ENV directives. The pTAL compiler issues a warning for any ENV directives that it

finds. Remove ENV COMMON and ENV NEUTRAL directives from pTAL programs.