FOR$ - FORTRAN Support Routines

FOR$ API	Function
FOR$CVT_D_TE	Converts decimal to text format
FOR$CVT_G_TE	Converts floating-point G format to text
FOR$CVT_H_TE	Converts hexadecimal to text
FOR$RAB	Handles Record Access Block (RAB) operations

What is VX/FOR$ and how does it help with FORTRAN migration?

VX/FOR$ provides a call-compatible implementation of OpenVMS Fortran runtime APIs for x86 and ARM Linux. It ensures that OpenVMS Fortran applications can execute seamlessly while preserving language features, execution behavior, and system interactions.

This tool eliminates the need to rewrite complex Fortran runtime dependencies, allowing organizations to migrate legacy applications efficiently. For migration planning and implementation support, contact our team.

What specific features does VX/FOR$ support?

VX/FOR$ supports data format conversion, record access management, runtime execution, and maintains OpenVMS Fortran execution semantics to ensure consistent behavior on Linux.

Which FOR$ API functions are supported?

VX/FOR$ supports key APIs including FOR$CVT_D_TE for decimal to text conversion, FOR$CVT_G_TE for floating-point G format conversion, FOR$CVT_H_TE for hexadecimal to text conversion, and FOR$RAB for Record Access Block operations.

How does VX/FOR$ integrate with other migration tools?

VX/FOR$ seamlessly integrates with VX/RT to provide full OpenVMS Fortran runtime capabilities on x86 and ARM Linux systems.

Can VX/FOR$ handle complex record access operations?

Yes, VX/FOR$ includes full support for Record Access Block (RAB) operations, which are essential for OpenVMS applications that perform complex file I/O and data management tasks. The tool preserves the original OpenVMS behavior for these operations on Linux.

Organizations like BNY Mellon have successfully migrated complex Fortran applications with similar record management requirements.

Does VX/FOR$ require code modifications during migration?

VX/FOR$ is designed to minimize code modifications by providing call-compatible implementations of OpenVMS FOR$ APIs, allowing direct porting of applications.

How does VX/FOR$ maintain OpenVMS compatibility?

VX/FOR$ maintains full compatibility with OpenVMS FOR$ runtime functions and preserves OpenVMS Fortran execution logic. This ensures that migrated applications behave identically to their original OpenVMS counterparts, reducing testing requirements and migration risks.

What are the benefits of using VX/FOR$ for Fortran migration?

VX/FOR$ delivers significant cost and time savings by preserving existing OpenVMS Fortran execution logic and enabling direct porting without major modifications. Organizations can maintain productivity while modernizing their infrastructure.

The tool supports key OpenVMS Fortran operations including data conversion and record access, ensuring comprehensive compatibility. Companies like Amprion GmbH have successfully leveraged similar runtime preservation strategies for complex Fortran applications.

VX/FOR$ minimizes development costs and accelerates migration timelines. To explore how VX/FOR$ can streamline your Fortran migration project, contact us for a consultation.

Which Fortran features are not supported by the new host compiler?

These are language constructs which are supported by VMS for which there are no simple syntactic translations to modern Fortran. The code must be re-structured. Usually, sub-programs must be called to supply the missing features.

Again, the VMS code will simply not compile or run without modification. The important issues are:

VMS File Names in OPEN and INQUIRE: VMS file names may contain device directory and version specifications. When these are specified in I/O statements they must be translated at run-time on the new host. This is done by calling sub-programs in Sector7's VXRMS library.
ISAM Files: Indexed Sequential Access Method files are files which contain linkage pointers from fields within their records to related records. Under VMS the OPEN, READ, WRITE and INQUIRE keywords are extended to support them. These extension are not supported under Linux, Unix or Windows. fpt handles ISAM files by replacing the OPEN, CLOSE, INQUIRE, READ and WRITE statements by calls to sub-programs in Sector7' VXRMS library.
Variables and Expressions in FORMAT Statements: Under VMS, variables and run-time expressions may be written inside FORMAT statements or in embedded format strings. The variables or expressions are written within < > delimiters. This construct is translated to standard Fortran using run-time format strings.

FOR$ - FORTRAN Support Routines

Overview

Key Features

VX/FOR$ Callable Routines

Why Use VX/FOR$?

Frequently Asked Questions

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