OpenVMS Demos: Programmer's Corner

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  1. The information presented here is intended for educational use by qualified OpenVMS programmers.
  2. The information presented here is provided free of charge, as-is, with no warranty of any kind.
  3. To the best of my knowledge, the programs presented on this web site compile, link and run properly. Please let me know if they don't work and I will attempt to fix them as soon as I find the time (I only support this stuff in my spare time).
  4. Is this text too small? You have two options:
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    2. use your keyboard like so:
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  5. SPECIAL ALERT: this area went through a major reorganization on 2015-11-07 with many of the 200+ sample programs being more-sensibly renamed
    1. If something has gone missing then send me an email: Neil Rieck
    2. Meanwhile, click here for a directory listing
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OpenVMS Source Code (presented in HTML format)


OpenVMS C/C++

Hybrid Programming

DCL (Digital Control Language)

Macro Assembler

OpenVMS Programming

Updated: 2015-11-23 (updated: mod_auth_vms_rms_c.)

OpenVMS Source Code (presented in HTML format)

Presented in HTML format so:

How my source code pages were webified

My demo programs were converted to HTML pages by running my source code through this VMS-BASIC-based utility:

What does it do? For the most part, it converts certain HTML-sensitive characters into HTML entities (meta data) like so:

Original Character HTML Entities
& &
< &lt;
> &gt;

The utility also inserts <pre> before my first line and appends </pre> after my last line in order to preserve spaces and tabs. Optionally, this utility can build a complete web page which saves me lots of time.


General Info Link: OpenVMS Notes: VMS-BASIC (coding techniques)

File I/O Demos

RMS :: Record Management Services for OpenVMS (ISAM)
RDB :: now Oracle-Rdb (Relational Data Base)
MariaDB :: An alternate fork of MySQL

RMS Export Tools

I/P Stack Demos (this code is written in BASIC; check out my C/C++ demos farther down this page)

TCPIP Services for OpenVMS
  1. a third-party stack from Process Software (supports IPv4 and IPv6)
  2. more feature-rich than TCPIP Services for OpenVMS from HP
  1. a third-party stack from Process Software (only supports IPv4)
  2. this was the only IP Stack for VMS in the 1980s and first half of the 1990s
  3. the Telnet API and FTP API provide a solution midway between Sockets and System Services

Web Demos

Apache Glue Example
Apache No-Glue Example
Password Change Demo
Upload Demo

Data conversion / manipulation

Miscellaneous Stuff

Command Line
DCL symbols
DECnet Communications
Device Scan
Diffie-Hellman Key Exchange Demo
Displaying System errors
Health Monitor
Lock Demos (CEF :: Common Event Flag)
Lock Demos (DLM :: Distributed Lock Manager)
Linked Lists and Memory Queues
Mailbox Demo (a.k.a. pipe)
When you need larger DCL symbols
Password Stuff
Population Simulation
system calls you can't live without
Source Code Tools
Terminal Characteristics
Timer Demos
VMS Mail

OpenVMS BASIC standalone functions (file extension ".fun")

Some BASIC demos may require these standalone (most BASIC) functions:

Question: So just what does the prefix WCSM stand for?
Answer: Waterloo Computer System Maintenance. That department morphed into something greater but the function prefix remains

OpenVMS BASIC includes (file extension ".inc")

Some BASIC demos may require these standalone includes:

My BASIC Development Environment

Here is a snapshot of my development environment. It will help you understand my includes

Directory File
[.dvlp] .bas
basic source code
DCL scripts for building some applications
[.dvlp.flb] .frm
FMS forms (created by dcl command: $fms yada.frm)
FMS form libraries
[.dvlp.fil] .rec
mapped string declarations (records) for relative and indexed files
open statements for relative and indexed files
file description language files for tuning rms files
[] .fun basic functions
[] .inc basic includes
[.dvlp.mar] .mar
macro-32 files
macro-64 files

BASIC Compiler bugs


  1.  I just (2012-08-01) discovered a bug in HP Alpha BASIC-1.7-000 (friends tell me it also exists on Itanium)
  2. Although you can divide large QUADWORD integers, the modulus function fails
  3. Here is a "C" version which works properly: basic_quad_mod_bug.c
  4. I just (2012-09-14) tested an experimental version of HP Alpha BASIC 1.7-001 which fixes this problem.
    Version Notes-1 Notes-2
    1.7-000 test fails at 2^32 bug
    1.7-001 test works up to 2^62 fixed
  6. CAVEAT: HP told me they will not be releasing this fix to the world so "if you have a support contract and want it fixed then you must input a support request"


  1. I just (2012-09-01) discovered a bug in HP Alpha BASIC-1.7-000 (friends tell me it also exists on Itanium)
  2. Although you can divide large DECIMAL integers, the modulus function fails
  3. I just (2012-09-14) tested an experimental version of HP Alpha BASIC 1.7-001 which fixes this problem.
    Version Declaration Notes-1 Notes-2
    1.7-000 decimal(16,0) test fails at 2^32 bug
    1.7-001 decimal(16,0) test works up to 2^53 fixed
      decimal(17,0) test works up to 2^56 with compile warnings safer to use quad
      decimal(18,0) test works up to 2^59 with compile warnings safer to use quad
      decimal(19,0) test works up to 2^62 with compile warnings safer to use quad
  5. CAVEAT: HP told me they will not be releasing this fix to the world so "if you have a support contract and want it fixed then you must input a support request"

BASIC RTL (run-time library) bug

p.s. I was attempting to write code which would directly open SYSUAF which contains a key (err, index) based upon an UNSIGNED QUAD. Since VMS-BASIC has no unsigned data types an updated BASRTL would be of no use. Even still, I am surprised to learn that this bug was hanging around since 2005 when HP added the QUAD data type to the language (up until then you needed to use BASIC$QUADWORD defined in the STARLET library)

DECC / DEC-C/ OpenVMS-C / OpenVMS-C++


Caveats for developers:
  1. both C and C++ languages "appear" to be more complicated on OpenVMS than what you will see on UNIX, Linux or Windows so be sure to read OpenVMS specific documentation.
    1. C on OpenVMS ( )
    2. C++ on OpenVMS ( )
    3. HP-C Run-Time-Library Reference Manual For OpenVMS which is used by both languages ( )
      • tells you where your libraries are located
      • compares UNIX I/O to RMS I/O
      • introduces optional directives which will allow UNIX-dependent c programs to run on UNIX
        • eg. translate a file system spec from "//one/two/three.dat" to "[one.two]three.dat"
    4. One definition of Sensei (a  Black Belt  in Karate) is "one is has gone before". Many times you will attempt to solve a problem which has already been solved by someone else long before. Some of these solutions can be found here:
      1. which includes lots of C sources like:
      2. which includes lots of C sources like:
  2. When calling OpenVMS routines defined in the STARLET library, do yourself a favor and enable strict type-checking. This is done by inserting ...

    #define __NEW_STARLET 1

    ... before the library references you wish to be strict (for new programs it should be before all libraries). This way, your code will be in better shape to be ported to another OpenVMS hardware platform. In one of the programs below (sys_create_uid_101.c) I needed to add a few more lines (resorted to a union) to satisfy the compiler but the optimizer was able to generate a program which was byte-for-byte the same size as and earlier relaxed version.
  3. Some large projects (especially code originally written for UNIX/Linux) may require you to build with a so-called "make utility". MMK is the name of the OpenVMS utility used by many developers and can be downloaded here:
  4. Lots of open-source software works under GNV (Gnu Not VMS): while a related effort can be located here:

C Demo Programs

C++ Demo Programs

Apache Specific

Apache Module Authentication



Source Code

gSOAP Specific (c)

When you check out the sample programs delivered with the gSOAP stack they seem fairly straight forward (right now I'm thinking about "calc") but most were created using the WSDL-last method. When someone hands you a WSDL then says "build client and server apps which will be part of a two way messaging system" things get complicated fast. You will be forced to use the WSDL-first method, and the tool wsdl2h (read as: wsdl-to-h) will stuff your SOAP variables deep inside complicated structures and unions then pass the whole mess to you with a pointer. If the WSDL contains more than 100 fields like the one I saw a few months ago, you might want to tackle a smaller project first just to develop skills.

Last year I used the WSDL-last method to create a Java-based web service under Tomcat/AXIS2 called "SimpleService". This service only had three methods: ssADD, ssSubtract, and ssEcho (I added the "ss" prefix to my variables so I would see them in various places in the code). Then I used AXIS2 to generate a WSDL which would be used to build this gSOAP service with the same functionality.

gSOAP demo web service

this WSDL was generated by AXIS2 (using:
this is a simple gSOAP client (add, subtract, echo)
this is a simple gSOAP service (add, subtract, echo)
this is a simple gSOAP service with a few more bells and whistles
the service requires this wrapper if you want to access it from Apache
common build script (DCL)
service build script (DCL)
client build script (DCL)
gSOAP demos (other)

this gSOAP sample client has been tweaked to support OpenSSL (demonstrates three different SSL client contexts)
doesn't do anything useful other than traversing a DOM-loaded SOAP packet (needs more work; would like to produce a better version in C++)
gSOAP reference
plugin code to allow Apache access to gSOAP (problems highlighted in yellow)
note: do not use this with OpenVMS (Brett Cameron has rewritten this plugin for his gSOAP distro)

gSOAP Specific (c++)

Brett Cameron and John Apps have provided a really good set of gSOAP sample programs written in HP-C but nothing (as of 2012) written in HP-C++. So here are my unofficial offerings of sample programs tweaked for use with HP-C++ for OpenVMS.

  1. Large gSOAP programs written in C++ seem clearer than the same ones written in C. Consider using C++ if you you want your gSOAP code to me more easily maintainable by other programmers.
  2. When the gSOAP preprocessor "soapcpp2" generates C++ code it will use a ".CPP" extension
  3. HP-C++ defaults to a file extension of ".CXX" while competing compilers default to ".CPP" so be sure to include a fully qualified file name.
gSOAP Calc Samples

gSOAP sample Client program from //gsoap/samples/calc++/calcClient.cpp
gSOAP sample Server program from //gsoap/samples/calc++/calcServer.cpp
DCL script to build these two gSOAP sample programs on OpenVMS
gSOAP sample Client program (w/OpenSSL) from //gsoap/samples/calc++/calcClient.cpp
(this last  demo has only been tested on Windows-7)

Porting OpenSSL to OpenVMS

While it is possible to build OpenSSL from public sources, the libraries will be okay but at least one of the demonstration applications will not work without modifications. The main reason for this involves use of the UNIX I/O select() statement to test for I/O readiness. While this is perfectly acceptable in the UNIX/Linux world, select() can only be used to wait for network I/O in the VMS and Windows worlds. There are two possible fixes for this:

  1. use a different technique to detect the start of keyboard I/O
  2. use a VMS-recommended technique to use a socket to connect to SYS$COMMANDND
Programs Notes
s_client.c This program was found in kit CPQ-OpenSSL-1.0A (OpenSSL 0.9.6b) published July 2001 by Compaq
It shows how to create a socket (TerminalSocket) to communicate with stdin (your keyboard)
No Compaq/HP copyright was included with this package.
While this program is copyrighted by Eric Young, the VMS changes are not copyrighted by anyone.
"I think" it was modified by someone at Compaq Computer Corporation
term_sock.c This program was found in kit CPQ-OpenSSL-1.0A and is used to create a socket (TerminalSocket) to communicate with stdin (your keyboard).
No Compaq/HP copyright was included with this package or this file.
"I think" it was written by someone at Compaq Computer Corporation.
It allows the programmer to get around the "bad select 38" problem
term_sock.h This c header supports term_sock.c
No Compaq/HP copyright was included with this package or this file.
"I think" it was written by someone at Compaq Computer Corporation
select_demo.c A demo program (derived from HP's UNIX to OpenVMS porting guide) to show how to use select() 

Webpage Hit Counters

We have always been told to never use hit-counters because they consume precious resources. But many rinky-dink sites, especially some on corporate intranets sitting behind a firewall, need them for good P.R. with other departments.

Image-based Counters

These seem to be the gold-standard in counters. Between 1995 and 2000 (when web servers were powerful platforms serving up mostly static webpages to underpowered desktop PCs sporting Pentium-2 or Pentium-3 processors) most sites used a bit of freeware written by Muhammad Muquit named "count". Needless to say I am envious of his programming skills. But this solution places a more-than-trivial computational burden on the server. Why? Updating a counter file is the easy part. Using the digits to reference a graphics library of individual digits then assemble the binary pieces scan-line by scan-line into a resultant GIF is the hard part.

Text-based Counters

I'm running an overworked decade-old server (AlphaServer DS20e installed in 2002) and I think the time has come to shift the computational burden from the server to the client. I have a little "C" program ready which increments the counter file then sends back the plain-text result. The calling webpage uses a small amount of AJAX (~20 lines) to accomplish the task then the browser is responsible for displaying the count. The browser may not have access to all the cool image sets seen in Muhammad's offering but that may not be as big a deal as you might think. I will publish it soon.


Web Page Hit Counter (2.4 + 2.6)

Technical Observations (2013-11-xx)
Updated DCL script for use with CSWS (aka Apache on OpenVMS)

$ on error then $ continue
$ t = f$cvtime(,,"TIME") -":"-":"-"."
$ p = f$getjpi("","pid")
$ f = f$trnlnm("csws_server_root") + "count_" + p +"_" + t +".gif"
$ set prot=(S:rwed,o:rwed,g:rwed,W:rwed)/default
$ define/user/nolog sys$output 'f'
$ mcr www_root:[scripts]count.exe
$ m=1 ! DCL
$ if (m.eq.0)
$ then ! MIME from a file
$	APACHE$DCL_BIN 'f';1 ! MIME header
$ else ! MIME from DCL
$!	write sys$output f$fao("!AS!/!/","Content-type: image/gif")
$	write sys$output f$fao("!AS!/!AS!/!/","Content-type: image/gif","Cache-Control: no-cache, no-store")
$ endif 
$ APACHE$DCL_BIN 'f';2 ! GIF data
$ del/nolog 'f';*
$ exit

Hybrid Programming

OpenVMS DCL scripts

Category DCL Scripts Notes
DECnet communication client (start a remote server then send it some messages) server (echo messages back to client)
Intercepting an
FTP/SFTP login
Example DCL script for properly setting up FTP/SFTP
DCL script to intercept an FTP/SFTP login then submit a login helper job
DCL script which will wait for the network partner to exit then process received file(s)
(similar to what happens at the end of an XCOM transaction)
More notes can be found here: OpenVMS Notes: TCPware
FTP Scripts a script which can FTP from three different stacks: MultNet, TCPware, and TCPIP Services
uppercase - lowercase
switcheroo a tool to easily toggle your account between two modes: case-sensitive and normal a tool to easily down-case filenames. Intended for SSH key files.
Apache Support a little batch job to rotate apache client log files every 24 hours
also will (optionally) do monthly maintenance of apache process logs
Monitoring (AXP only)
original script
tweaked for calling from your LOGIN.COM

OpenVMS Macro32 source code

Programs Notes
peek_byte_vax.mar Code to peek at bytes
peek_byte_function.mar Code to peek at bytes (function)
peek_any_int_vax.mar Code to peek at bytes, words, and longs

OpenVMS Programming

Introduction to OpenVMS programming

It was a lot tougher before y2k

It was a lot tougher learning how to write VMS applications in the 1980s. Why? DEC charged big-bucks for everything including hardware, software, training and documentation (including pocket programming cards!) Many IT people wondered if that was why DEC used a dollar sign ($) for the VMS/DCL command-line prompt.

First off, you needed the 32-binder  Orange Wall of VMS documentation  which I remember being around $5k for the initial purchase. Then, even if you already knew how to program in one of the many DEC-supported programming languages, you still needed to attend DEC language-specific courses to learn how to do system calls. This meant you needed to work for a company with deep pockets, or needed to get VMS-specific training in college or university.

In the early 1990s, DEC renamed the product line from VMS to OpenVMS at the same time they introduced the 64-bit Alpha hardware line as a successor to 32-bit VAX. During this time the  Orange Wall  became the  Gray Wall  

Then Things Changed

In 1998, DEC was purchased by "PC manufacturer" Compaq.

In 2002, HP purchased (err, merged with) Compaq. HP restored some in-house training but now OpenVMS was just one of many software offerings from HP's, and I think OpenVMS has been lost in the mix.

Although my employer did provide us with the 32-binder Gray Wall, we had to learn how to interface VMS BASIC to VMS the good old-fashioned hard way: by hacking. In 1993 I fortunately stumbled across a copy of Writing VAX/VMS Applications Using Pascal (Author: Theo De Klerk, Published: 1991 by Digital Press) in DEC's student retail store in Bedford, Massachusetts. I had learned Apple Pascal in late 1970s so found it relativity easy to convert many of these programs into DEC-BASIC and DEC-C. This book contained many descriptions of VMS subsystems and was full of "system calls" on how to access them. These books pop up every so often on and I think every serious OpenVMS programmer should own a copy.

Okay so that was then and this is now. To the best of my knowledge, you can only get the OpenVMS Documentation CD-ROM by purchasing it from HP, buying a used copy on eBay, or begging a friend to make you a copy. But if you use HP's online documentation along with examples from this book, you will learn how to become a VMS BASIC developer much faster than me.

Online HP Manuals + Documents

Advanced hacking (system services)

Many novice programmers do not know about this cool feature to trace system calls originating from your process (DCL or otherwise). So if you have the necessary privs, then try this experiment:
  <sr> = system response <ur> = user response -------------------------------------------------------- <sr> $
<ur> set process /sslog=(state=on,count=4) ! enable tracing on YOUR process
<sr> $
<ur> monitor disks <sr> screen fills with disk i/o statistics <ur> now wait for 4 or 5 seconds then hit <ctrl-c> <sr> MONITOR> <ur> exit <sr> $ <ur> set process /sslog=(state=off) ! disable tracing <sr> $ <ur> set process /sslog=(state=unload) ! this closes the file <sr> $ <ur> ANALYZE/SSLOG/FULL/WIDE/OUTPUT=ss_trace.txt ! human readable data goes to this file <sr> $

Official Documents:

Noteworthy C/C++ demos at other sites

Noteworthy C/C++ articles and manuals

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Neil Rieck
Kitchener - Waterloo - Cambridge, Ontario, Canada.