Compaq COBOL is based on and is highly compatible with Compaq COBOL for OpenVMS VAX, which runs on the OpenVMS VAX system. However, there are differences, which are summarized in this appendix. This information can help you develop COBOL applications that are compatible with both products and can help you migrate your Compaq COBOL for OpenVMS VAX applications to Compaq COBOL on the OpenVMS Alpha operating system, the Tru64 UNIX operating system, or the Windows NT Alpha operating system.

B.1 Compatibility Matrix

Table B-1 shows the current (as of the date of publication of this manual) state of compatibility for numerous features in Compaq COBOL Version 2.7 on its three platforms and Compaq COBOL for OpenVMS VAX Version 5.7. Always check the Release Notes for the latest developments if there is a question about the availability of a given feature.

Legend X = Supported N = Not supported P = Partially supported

Table B-1 Cross-Platform Compatibility of COBOL Features

	OpenVMS VAX	OpenVMS Alpha	Tru64 UNIX	Windows NT Alpha
ANSI-85/-89 HIGH	X	X	X	X
ANSI-85 REPORT WRITER	X	X	X	X
Standard arithmetic	N	P	P	P
Table sort	N	X	X	X
Tape handling	X	X	X	N
Segmented keys	X	X	X	X
/CHECK=DUPLICATE_KEYS	X	X	N	N
Relaxed key checking	N	N	X	X
RMS special registers	X	X	N	N
RMS APPLY extensions	X	X	N	N
/STANDARD=V3	X	P	P	P
ANSI-74 FILE STATUS support	X	X	X	X
VFU	X	N	N	N
Print control files with VFC	X	X	N	N
Print control files without VFC	N	X	X	X
ISAM READ PRIOR/START LESS	N	X	X	X
Extended ACCEPT/DISPLAY	X	X	X	X
ACCEPT/DISPLAY BLINK	X	X	X	N
ACCEPT/DISPLAY WITH CONVERSION	X	X	X	X
ACCEPT/DISPLAY VT52 support	X	N	N	N
ACCEPT/DISPLAY VT{1,2,3,4}xx support	X	X	X	N
ACCEPT support for four-digit years	X	X	X	X
Y2K intrinsic functions	X	X	X	X
File sharing / rec locking	X	X	P	P
UCX/NFS support (nolocking)	N	N	X	X
FUNCTION ARGCOUNT	X	X	N	N
Little-endian COMP data	X	X	X	X
31-digit user items	N	X	X	X
18-digit intermediates	X	X	X	X
32-digit intermediates	N	X	X	X
F,D floating	X	X	N	N
G floating	N	X	N	N
IEEE S,T floating	N	X	X	X
Floating point "E" literal	X	X	X	X
64-bit pointers	N	P	X	N
SYS$CURRENCY	X	X	N	N
Invalid decimal data checking	P	P	P	P
X/Open RETURN-CODE	N	X	X	X
X/Open COMP-5/COMP-X	N	X	X	X
X/Open LINE SEQUENTIAL	N	X	X	X
X/Open ASSIGN TO	N	X	X	X
X/Open SCREEN SECTION	N	X	X	X
X/Open SCREEN SECTION color	N	X	X	X
X/Open SCREEN SECTION BLINK	N	X	X	N
X/Open DISPLAY ON EXCEPTION	N	X	X	X
X/Open file sharing / rec locking	N	X	X	X
X/Open environment variables	N	X	X	X
X/Open command line	N	X	X	X
/CHECK=(PERFORM,BOUNDS)	X	X	X	X
VAX compatible alignment	X	X	X	X
Alpha natural alignment / padding	N	X	X	X
Targetted code generation / optimization	X	X	X	X
/[NO]SEPARATE_COMPILATION	P	X	N	N
I18N (PIC N, etc.)	X	X	X	X
CALL USING BY DESCRIPTOR	X	X	N	N
cobfunc, cobcall, and cobcancel	N	X	X	X
Reformat	X	X	X	X
Terminal source format	X	X	X	X
Lowercase, -/_ in source	X	X	X	X
Sample Application - Client/Server	N	N	N	X
Sample Applications - Visual Basic calling COBOL	N	N	N	X
Oracle CDD/DML support	X	X	N	N
Transarc Encina (-tps) support	N	N	X	N
DECset PCA,LSE/SCA support	X	X	N	N
DECset PDF support	X	N	N	N
FUSE support	N	N	X	N
Interactive compiler driver	N	N	N	X
Symbolic debugger support	X	X	X	X

B.2 Differences in Extensions and Other Features

Compaq COBOL contains the following language extensions and other features that are not in Compaq COBOL for OpenVMS VAX:

• A choice of alignment (with the /ALIGNMENT qualifier) on the compile command line or as a source directive for individual records; you can select Alpha data alignment to optimize performance or Compaq COBOL for OpenVMS VAX data alignment for compatibility with Compaq COBOL for OpenVMS VAX.
• A flag or qualifier (/ARCHITECTURE or -arch ) that enhances performance through targeted code generation.
• A flag or qualifier (/ARITHMETIC or -arithmetic ) that selects native or standard arithmetic.
• A flag or qualifier (/CONVERT=LEADING_BLANKS or -convert leading_blanks ) that changes all blanks to zeros in numeric display items in arithmetic expressions or statements.
• A flag or qualifier (/DISPLAY_FORMATTED or -display_formatted ) that causes the proper display of numeric values without the use of WITH CONVERSION on the DISPLAY statement.
• A qualifier (/FLOAT, on the OpenVMS Alpha operating system) that selects IEEE or VAX floating-point data types for single- and double-precision data items. <>
  On Windows NT and the Tru64 UNIX operating system, only IEEE floating point is supported. <>
• A flag or qualifier (/INCLUDE or -include ) to control where the compiler searches for files for simple COPY statements.
• A flag or qualifier (/MATH_INTERMEDIATE or -math_intermediate ) to specify the intermediate data type for extended arithmetic precision and/or compatibility.
• A flag or qualifier (/OPTIMIZE=TUNE or -tune ) that improves optimization through instruction scheduling, and a choice of levels of optimization (with /OPTIMIZE=LEVEL).
• A flag or qualifier (/RESERVED_WORDS or -rsv ) to recognize or not to recognize additional COBOL reserved words defined by the X/Open Portability Guide, words that are foreign extensions, or selected words that are reserved as defined by the draft ANSI Standard for COBOL.
• A qualifier (/TIE, on the OpenVMS Alpha operating system) to generate code that allows native OpenVMS Alpha images to call translated VAX images and translated VAX images to call native OpenVMS Alpha images. <>
• COMP-5 and COMP-X as synonyms for COMP.
• READ PRIOR and START LESS.
• X/Open ASSIGN TO, LINE SEQUENTIAL, RETURN-CODE, SCREEN SECTION, FILE-SHARING and RECORD-LOCKING.

Compaq COBOL does not contain the following Compaq COBOL for OpenVMS VAX features:

• The DECset/LSE Program Design Facility, the /DESIGN qualifier, design comments, or pseudocode placeholders.
• VFU-CHANNEL. Because Compaq COBOL does not support VFU-CHANNEL, it provides no direct support for VFU and VFP (Vertical Forms Unit utilities and Vertical Forms Printing).

Compaq COBOL includes the following:

• Support for the relevant subset of the features in the Compaq COBOL for OpenVMS VAX /STANDARD=V3 qualifier. See Section B.3.3.
• Support for file status values that are compatible with Compaq COBOL for OpenVMS VAX Version 5.1 or higher. These differ from those of Compaq COBOL for OpenVMS VAX Version 5.0 and previous versions.

Sections B.3.1, B.3.2, and B.3.3 compare the Compaq COBOL and Compaq COBOL for OpenVMS VAX command-line qualifiers and the equivalent command-line flags (options) on Windows NT and Tru64 UNIX operating systems. For complete information about Compaq COBOL command-line qualifiers on the OpenVMS Alpha operating system, invoke the online HELP facility: Type HELP COBOL at the OpenVMS Alpha system prompt. For complete information on the flags, see the man page: Type man cobol at the Tru64 UNIX system prompt. For information about Compaq COBOL for OpenVMS VAX command-line qualifiers, see the VAX COBOL User Manual.

B.3.1 Qualifiers and Flags Shared by Compaq COBOL and Compaq COBOL for OpenVMS VAX

Table B-2 lists the OpenVMS command-line qualifiers shared by Compaq COBOL and Compaq COBOL for OpenVMS VAX and the equivalent Compaq COBOL flags and options on the Windows NT and the Tru64 UNIX operating systems.

Table B-2 Qualifiers Shared by Compaq COBOL and Compaq COBOL for OpenVMS VAX and Equivalent Flags and Options

OpenVMS Qualifier, Windows NT Option	Equivalent Tru64 UNIX Flag1
/ANALYSIS_DATA 3	None
/ANSI_FORMAT	-ansi
/AUDIT 3	None
/CHECK 2	-check
/CONDITIONALS	-conditionals
/COPY_LIST	-copy_list
/CROSS_REFERENCE	-cross_reference
/DEBUG	-g
/DEPENDENCY_DATA 3	None
/DIAGNOSTICS 3	None
/FIPS 2	-fips 74
/FLAGGER	-flagger
/LIST	-list
/MACHINE_CODE	-machine_code
/MAP	-map
/NATIONALITY={JAPAN|US}	-nationality {japan|us}
/OBJECT	None
/SEQUENCE_CHECK	-sequence_check
/STANDARD 2	-std
/STANDARD=MIA	-std mia
/TRUNCATE	-trunc
/WARNINGS 2	-warn

/NATIONALITY={JAPAN|US}, -nationality japan

When /NATIONALITY=JAPAN or -nationality japan is specified, the yen sign (¥) is the default currency sign and symbol, and Japanese Language Support features are enabled. Also, in this case /NODIAGNOSTICS and /NOANALYSIS_DATA are specified implicitly.

Oracle CDD/Repository is not supported by Compaq COBOL on OpenVMS Alpha when /NATIONALITY=JAPAN is used.

When /NATIONALITY=US or -nationality us is specified on the compile command line, the dollar sign ($) is the default currency sign and symbol, and Japanese Language Support features are disabled.

/STANDARD=MIA, -std mia

If /STANDARD=MIA or -std mia are present on the compile command line, the compiler will issue informational diagnostics for those language elements that do not conform to the MIA specifications:

• Compaq syntax extension from Base Standards (ANSI-85, JIS-88)
• Two of four optional modules
• All obsolete language elements of required modules in Base Standards
• Language elements omitted from required modules in Base Standards due to the different implementation of the vendors
• Compaq specific Japanese features out of MIA Extension Elements related to Japanese

To receive the diagnostics, the -warn all flag, /WARNINGS=ALL qualifier, -warn information flag, or /WARNING=INFORMATION qualifier is required.

The default is NOMIA.