IBM OS/390 User Manual

Page of 673
Chapter 15. PL/I
The PL/I language compiler implemented on VSE is the DOS PL/I Optimizing
Compiler (5736-PL3). In MVS, the PL/I language is implemented by the OS PL/I
Optimizing Compiler Version 1 (5734-PL3), and OS PL/I Version 2 Optimizing
Compiler (5668-910).
As the OS PL/I Version 2 Optimizing Compiler implements more of the PL/I
language than Version 1 does, most source programs compiled on the VSE
compiler can be compiled on either of the two MVS compilers with a minimum
amount of change.
Note:
The most current version of PL/I is PL/I for MVS & VM Version 1, Release
1. This compiler produces object code designed to run under Language
Environment, a common run-time environment for several languages on this
platform. Please refer to the 
IBM PL/I for MVS & VM Compiler and Run-Time
Migration Guide Release 1.1, SC26-3118 for assistance with your migration to
Language Environment.
For a comparison of VSE PL/I and MVS PL/I language elements, see the
publication entitled 
Developing Portable VSE Applications, GC33-6367.
15.1 Functional Differences
15.1.1 EGCS (VSE) to DBCS (OS Version 2) Comments
The following information is provided to those PL/I users who are currently using
DOS PL/I Optimizing Compiler
s Extended Graphic Character Set (EGCS)
support. The Version 1 OS PL/I compiler also has the EGCS support. The Version
2 OS PL/I compiler made enhancements to EGCS support and renamed the
support, Double Byte Character Set (DBCS).
EGCS support is limited to support for the GRAPHIC string constant and
GRAPHIC data type. It introduced the GRAPHIC compiler option, which allows
the installation (but not the user) to define the graphic control characters. These
control characters consist of the shift-in, shift-out, graphic blank, graphic quote
and graphic letter 
G
′. 
The format of the graphic string constant (with a graphic
G
′ 
suffix) is fixed.
DBCS support provides for additional new function (including free-format input)
over that provided with EGCS. For a comprehensive list of the DBCS support
items, see
 OS PL/I Version 2 Language Reference, SC26-4308 and the OS PL/I
Version 2 Programming Guide, SC26-4307.
VSE migrations to the OS PL/I Version 2 product, should not experience any
code problems given that they didn
t modify EGCS code points; that is, upward
compatibility is provided.
 Copyright IBM Corp. 1998 
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