Chapter 4: Migrating Unmanaged COBOL to .NET

This chapter identifies the main issues with migrating unmanaged COBOL to .NET managed COBOL.

Introduction

The majority of COBOL programs can be recompiled as .NET managed code without change.

Some programming techniques and COBOL syntax and features are applicable to unmanaged COBOL only and not to .NET managed COBOL. If you have a COBOL program that uses any of the above, you need to modify the program to use .NET techniques instead, before compiling the program as managed COBOL.

For details on how to migrate Net Express projects to Visual Studio projects, see Backward Compatibility.

Migrating Specific Technologies

The following technologies have migration issues and solutions as follows:

Mixed language programs
NonCOBOL projects that call COBOL code require a reference to the MicroFocus.COBOL.Runtime assembly.
Java interfaces
Any Java interfaces that you created using Net Express can continue to run under Micro Focus Server.
OO COBOL
All object references must be defined at level 01, because the compiled code and the runtime system now confirm to .NET rules for type safe code. This conforms with the ISO2002 COBOL standard.
Web Services
Any Web Services that you created using Net Express can continue to run under Micro Focus Server. These Web Services can interoperate with new .NET managed code. This is recommended.

Web Services that are already deployed and running on Micro Focus Server cannot easily be migrated to a .NET managed environment. Similarly, Web Services that you created using Net Express cannot be deployed directly to a .NET managed environment. You need to migrate your code to .NET before creating the Web Services (for .NET) from the migrated code.

COBOL Syntax Restrictions

Some COBOL syntax is available for unmanaged COBOL only and not for .NET managed COBOL. If you have a COBOL program that uses this syntax, you need to use .NET techniques instead, before compiling the program as managed COBOL.

The following syntax is restricted to unmanaged COBOL:

ACCEPT statement format 5.
ADIS (Extended Accept/Display).
ALTER statement. This is supported but in segmented programs, an altered paragraph remains altered even when a segment is reloaded.
CALL-CONVENTION
CHAIN statement. This is mapped to a CALL statement.
DISPLAY of numeric fields. A signed numeric field displays an integer. Plus signs are not displayed.
DISPLAY statement format 3.
GLOBAL declaratives in nested programs.
Mainframe pointers.
Mainframe performs (perform-type(osvs/vsc2)).
Program names. Generally, .dll names, program names and method names used in CALL and INVOKE statements must always be specified in upper case. However, if the AS phrase has been used in the called program to modify the program name, the case used in the CALL or INVOKE statement must exactly match that specified in the AS phrase.
Screen section.

Some new syntax is available for .NET managed COBOL and some additional words are now reserved. If your unmanaged code uses words that are now reserved, your code will not compile. You can unreserve the necessary words, by using the REMOVE Compiler directive. See REMOVE.

Compiler Directives Restrictions

The following Compiler directives are not supported for .NET managed COBOL:

ACTUAL-PARAMS
BOUNDOPT
CHECK
COBIDY
FASTCALL
FASTLINK
FAULTFIND
FIXOPT
GNT
HOSTSIGNS
INT
INTLEVEL
KEEP-INT
LINKCHECK
LITLINK
LNKALIGN
OBJ
OMF
OPT
PARAMCOUNTCHECK
PERFORMOPT
RECURSECHECK
SCHEDULER
SEG
SOURCEASM
TRICKLE
WEBSERVER

See Known Errors for details of directives not yet supported.

SQL Restrictions

The following restrictions apply to the use of SQL in .NET managed COBOL:

Dynamic SQL using the SQL Descriptor Area (SQLDA) is not supported for either OpenESQL applications compiled with the SQL(DBMAN=ODBC) directive, or DB2 applications compiled with the DB2 directive
CONNECT ... WITH PROMPT syntax is not supported with applications compiled with SQL(DBMAN=ADO)

File Handling Restrictions

The following file handling features are not supported in .NET managed COBOL:

FileShare
.lbr files
LPT[2-n] devices
Printer re-direction
Timeout support within the support for LPT1

The Managed Code File Handler is not verifiable.

Functionality Restrictions

Some COBOL functionality is available for unmanaged COBOL only and not for .NET managed COBOL. If you have a COBOL program that uses this functionality, you need to use .NET techniques instead, before compiling the program as managed COBOL.

The following functionality is restricted to unmanaged COBOL:

Some CBL_ and PC_ routines (the majority are supported)
ANSI debug
CGI
CICS commands
Micro Focus class libraries

OO COBOL Restrictions

The following features of OO COBOL are not supported in .NET managed COBOL:

Multiple inheritance
The OO class library
The CLASS-OBJECT syntax

All object references must be defined at level 01, because the compiled code and the runtime system now confirm to .NET rules for type safe code. This conforms with the ISO2002 COBOL standard.