VX/RT APIs

Overview

VX/RT is a call-compatible library that enables OpenVMS applications to run without modifications on RedHat and SUSE Linux. It faithfully replicates over 900 OpenVMS system service calls, ensuring that API behavior, argument structures, return codes, and error handling remain identical to the original VMS environment.

Key Features of VX/RT

Feature	Description
Call-Compatible API	Recreates the behavior of over 900 VMS / OpenVMS APIs in native C and C++.
Seamless File Specification Handling	Accepts VMS-style file specifications, logical names, and search lists, translating them dynamically to Linux format.
Identical Error Code Mapping	Translates Linux/Windows errors to VMS error codes (e.g., `ENOFILE` → `RMS$_FNF`).
Full RMS Compatibility	Provides a complete ODBC-accessible RMS environment, supporting FAB, RAB, NAM, and XAB structures.
Event Flags & IPC	Supports VMS-style event flags, inter-process communication (IPC), and shared memory.
Logical Name & Symbol Tables	Replicates VMS logical name tables and symbol management, ensuring seamless cross-process communication.
Timers & Asynchronous System Calls	Implements VMS-style timers, AST event handling, and asynchronous I/O operations.
DCL & CLI Compatibility	Includes VX/DCL, a fully functional VMS / OpenVMS DCL shell for Linux, along with VX/CLI for command parsing.
Batch & Print Queue Support	Implements VMS batch and print queue management (SYS$SNDJBC, SYS$GETQUI, etc.).

VX/RT System Services

VX/RT provides call-compatible implementations of major OpenVMS runtime libraries and system services.

Supported System Services:

• File Management: SYS$OPEN, SYS$SEARCH, SYS$RENAME, SYS$DELETE

• Process Control: SYS$CREPRC, SYS$DELPRC, SYS$HIBER, SYS$WAKE

• Inter-Process Communication: SYS$SNDJBC, SYS$GETQUI, SYS$GETMSG

• Timers & AST Handling: SYS$SETIMR, SYS$CANTIM, SYS$SCHDWK

• Memory Management: LIB$GET_VM, LIB$FREE_VM, LIB$CREATE_VM_ZONE

• String & Math Libraries: STR$, MTH$, OTS$

VMS Library Support:

BAS$ - BASIC Runtime Support - Fully compatible BASIC runtime for OpenVMS applications on Linux, ensuring seamless execution.
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CLI$ - OpenVMS Command Interface - CLI interpreter replicating OpenVMS behavior, ensuring command procedures work on Linux.
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COB$ - COBOL Support Routines - COBOL runtime for OpenVMS applications, preserving compatibility with system calls and logic.
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CONV$ - File Conversion - Converts OpenVMS file formats into Linux-compatible structures while preserving data integrity.
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CVT$ - Data Conversion Utilities - Handles OpenVMS data format conversions, ensuring seamless migration to Linux systems.
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EDT$ - Callable Editor - Provides an OpenVMS EDT-compatible text editor for interactive and programmatic use.
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EXE$ - Operating System Interface - Supports OpenVMS process execution and image management on Linux environments.
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FDL$ - File Definition Language - Provides a call-compatible implementation of OpenVMS File Definition Language (FDL$) APIs for x86 and ARM Linux.
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FDV$ - Forms Management System - Implements OpenVMS compatible forms processing and user interaction handling.
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FOR$ - FORTRAN Support Routines - Provides OpenVMS Fortran runtime support, preserving language features and execution behavior.
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FORMS$ - DECFORMS Integration - Supports DEC Forms-based applications, maintaining structured UI and user interaction logic.
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LBR$ - Callable Librarian - Implements OpenVMS library management routines, preserving archive and module handling.
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LIB$ - General Routines - Provides OpenVMS general-purpose utilities, including string, math, and system functions.
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MTH$ - MATH Routines - Implements OpenVMS compatible mathematical functions, ensuring precision and compatibility.
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OTS$ - Data Conversion Routines - Supports OpenVMS style data conversion, encoding transformations, and structured data handling.
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PAS$ - PASCAL Support Routines - Enables OpenVMS Pascal applications to run on Linux while preserving language semantics.
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SMG$ - Screen Management - Implements OpenVMS screen management routines for interactive and terminal-based applications.
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SOR$ - Interface to SORT - Provides an OpenVMS-compatible sorting interface for structured data processing.
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SQL$ - SQL Database Interface - Supports SQL-based data access for OpenVMS applications, preserving query execution behavior.
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STR$ - STRING Interface Routines - Implements OpenVMS-style string processing functions, ensuring compatibility with existing applications.
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SYS$ - System Interface Routines - Implements core OpenVMS system service calls, ensuring full execution compatibility on Linux.

Why Choose VX/RT?

✅ Migrate OpenVMS applications to Linux with minimal changes

✅ Retain existing API calls, file structures, and application logic

✅ Preserve RMS data integrity and record locking mechanisms

✅ Replicate VMS batch processing, DCL commands, and logical name handling

✅ Seamless integration with VX/DCL, VX/RMS, and other Sector7 tools

VX/RT ensures VMS applications remain operational in modern Linux environments, eliminating the need for costly rewrites or extensive retraining.