OpenVMS Demos: Programmer's Corner

Updated: 2024-11-15

OpenVMS Source Code (presented in HTML format)

Presented in HTML format so:

• Google can index them
  • you can search them with "Google proper"
  • you can search them with "Google site-search" like so: site:neilrieck.net  lib$spawn (just drop this red text into a Google search to see what I mean)
• you can display them with a browser (tab characters are rendered properly with modern browsers)
• you can drag a cursor over source text then copy-paste into an EDT editor (provided you are using a good terminal emulator)

How my source code pages were webified (is that a real word?)

These demo programs were converted to HTML pages by running the source code through this VMS-BASIC utility ( tool_webify_source_code.bas ) which converts certain HTML-sensitive characters into HTML entities then generates a complete web page

OpenVMS Python demos

• Why use Python? Read my introduction to learn how Python bypasses usual 64-bit limitations
  • here I am talking about native math support languages like BASIC, C, C++ etc. Many developers get around these limitations by writing, or purchasing, a math library
• Logical Name Demo.py (also shows how to access STARLET definitions)
• Python JIT Compiler (on OpenVMS)

OpenVMS BASIC demos

People new to VMS-BASIC might wish to read these articles:

• OpenVMS BASIC Introduction (another web page)
• OpenVMS BASIC Optimal Coding (another web page)

File I/O Demos

RMS - Record Management Services for OpenVMS

comments:

1. Back in the day, many hardware vendors also sold their own proprietary operating systems. IBM (International Business Machines) and DEC (Digital Equipment Corporation) both incorporated support for sequential and relative data records into their respective operating systems in order to facilitate COBOL-74.
2. Then they both included support for sorted indexed records in order to support COBOL-80 which was finally released as COBOL-85. IBM invented the name ISAM which contains all three technologies.
3. On DEC systems, like VMS and OpenVMS, indexed ISAM can be seen in action by examining the system account file.
   Type this DCL command dir sys$system:SYSUAF.DAT /full to see what I mean
4. COBOL uses PIC statements to layout record structure (PIC is short for PICTURE). VMS-BASIC employs MAP statements

program files

• rms_sequential_demo.bas
  • shows how to manipulate sequential RMS files (text files are one example)
• rms_relative_demo.bas
  • shows how to manipulate relative RMS files
• rms_indexed_demo.bas
  • shows how to manipulate indexed RMS files (ISAM = Indexed Sequential Access Method)
  • this is a vanilla green screen demo
  • comment: many software manufacturers, including IBM and DEC incorporated ISAM into their operating systems in order to support COBOL
• rms_indexed_demo_fms.bas
  • shows how to manipulate indexed RMS files (ISAM = Indexed Sequential Access Method)
  • this is an FMS-based green screen demo
    • you will need this FMS form: rms_indexed_demo_fms.zip
    • you will need this FMS include: fms_fdvdef.inc
    • you will need this other include: device_controls.inc
    • FMS (Forms Management System) Notes:
      • during the VAX/VMS era, developers were encouraged to insert their various FMS forms (name1.frm) into a developer-created "forms library" (name.flb). Just after image activation, your program would call FDV$LOPEN to open the library, then call FDV$LOAD to fetch the forms into workspace buffers in your program, then call FDV$LCLOS to close the library channel. In those days I went to great lengths to reduce the cost of disk i/o on our under-powered while overworked VAX platforms. One solution was to bypass the form library by creating a binary version of each form at compile-time, then linking them to the executable. The FMS demo shows you how to do this.
      • There are ~ 66 FMS functions and you can read more about them by downloading manuals from here: https://docs.vmssoftware.com/
      • caveat1: many FMS-based solutions were migrated to a newer API called DECForms which has fewer functions with more parameters
      • caveat2: back in the day, we would present these small skeleton programs to new programmers entering our group (the might have been familiar with BASIC, but not DEC-BASIC or DEC-RMS or DEC-FMS). I recently used them to debug a new implementation of FMS on OpenVMS-9.2-3 on x86-64. You may find them useful if you are doing something similar: https://neilrieck.net/misc/zip/openvms/basic-fms-demos2.zip
• rms_test_fsp.bas
  • a little hacking with the FSP$ function (originally provided to do a trial file-open on BASIC-PLUS-2 programs)
  • newer programs should only use USEROPEN (see next demo)
• rms_test_useropen.bas
  • do a trial file-open using a USEROPEN function
    • an intermediate version includes a hack to allow inclusion of XABSUM and XABKEY (this last one is for inspecting keys a.k.a. indexes)
    • recently added code to include XAMPRO (to inspect protection bits)
    • this program works in two modes:
      • simple-and-safe:
        • simply tack my pointer onto the existing FAB:XAB pointer (overwriting what was their previously)
        • do my thing
        • restore original pointer before exiting USEROPEN
      • complex-and-dangerous:
        • start at FAB:XAB then scan the linked list until you hit a zero. Then use a home-grown POKE routine to tack my list onto the end of the existing list
        • do my thing
        • restore original pointer before exiting USEROPEN
• sys_file_io_demo.bas
  • doing file i/o in BASIC without using BASIC's file i/o routines
• read_sysuaf.bas
  • directly reading SYSUAF records for audit purposes only (you need lots of privs just to open SYSUAF.DAT)
  • however, I also used this code to move client records from my VMS system into a relational database (I wanted to support application-level authentication without allowing access to VMS proper; information here allowed me to move active VMS accounts into an application-level database without needed to reset passwords)

RDB - Oracle-Rdb (Relational Data Base)

• DEC intended RDB to be the successor to RMS which they sold to Oracle Corporation in the 1990s
• you can find the original 43-file zipped package here
• More information: OpenVMS Notes: Oracle-Rdb

MariaDB - An alternate fork of MySQL

• Click here to view several VMS-BASIC demos where I call the MariaDB client via the C-API. People wanting to use MySQL would only need to slightly modify the build script.

Tools: RMS Export - MySQL Import

• mysql_import_helper.bas
• mysql_import_helper_basic_template_part1.bas
• mysql_import_helper_basic_template_part2.bas
• mysql_import_helper_basic_template_part3.bas
• In 2014, our primary business system consisted of ~ 70 BASIC programs reading/writing ~ 150 RMS indexed files. In order for us to do a parallel operations (RMS=production, MySQL=daily snapshot for ad-hoc queries) over the next 12 months, we needed a semi-autonomous method of tool generation. These four BASIC programs do the following:
  • generate 99% complete BASIC programs to extract data from RMS files then write it to CSV files
    • you only need to edit one line before compiling (the input file name)
    • generic open/read of your RMS files (bypasses indexes/keys)
    • this tool is preferable to opening up your source code to insert customized export routines
    • once built, there is no need to do this again unless the RMS file format changes
  • generate 99% complete SQL scripts to create the tables then import the data from CSV files
    • since my tool does not (yet) analyze the OPEN statements, you will need to insert SQL statements to create constraints, indexes and keys, etc.
    • CAVEAT: you could modify the table creation statements before the import but this would cause the import to be hundreds of times slower (lots of recursion while it maintains each index AND you could still end up with a lop sided index if the inserted data was already ordered). All large imports should always be indexless and constraint-less; you tack them on as a finishing step.
    • I placed all my post-import SQL statements in a second script which won't be overwritten by the tool
• 2015 Update: after 12 months or so, many of our programs are bypassing RMS and writing production data directly into MariaDB. This means that these transfer tools are taking a back seat to our daily operations. We expect to have everything moved out of RMS by the end of 2019.
• 2020 Update: we still have five RMS-ISAM files which have not yet been permanently moved to MariaDB so I updated the four programs above to do a better conversion from mixed to latin1 (cp1252)

I/P Stack Demos (written entirely in VMS-BASIC)

• click here to see my c-demos farther down this page

TCPIP Services for OpenVMS

• TCPIP Services for OpenVMS is HPE's official IP stack for OpenVMS
  • IIRC, there was never a version of "TCPIP Services for VMS on VAX" which is why most VMS sites ran TCPware from Process Software
  • versions 4.x and lower produce logical names prefixed with "UCX" ("UNIX Communications Extensions" or "Ultrix Communications Extensions")
  • versions 5.0 and higher produce logical names prefixed with "TCPIP"
    • later versions of 5.x support both IPv4 and IPv6
• Notes:
  • the demo programs just below where written in 2014 when I was preparing to move from TCPware on Alpha to MultiNet on Itanium
    • Why change? In 2014, PSC told us that TCPware only supported IPv4 and never would support IPv6
    • Much of our home-grown apps were dependent upon a TCPware API known as the TELNET Library (nothing equivalent in any other stack)
    • These demos were developed on TCPIP Services (the machine I was working on at the time did not have have a MultiNet license)
    • these programs employ VMS System Services rather than the Sockets API so will work with any stack
• tcpip$tcp_client_qio_2014a.bas
  • Synchronous (qiow) TCP client demo - employs http to retrieve a web page
• tcpip$tcp_client_qio_2014b.bas
  • Synchronous (qiow) TCP client demo - adds support for gethostbyname
• tcpip$tcp_client_qio_2014c.bas
  • Asynchronous (qio) TCP client demo - employs programmable timers
• tcpip$tcp_client_qio_2014d.bas
• tcpip$tcp_client_qio_2014d.inc
  • Same as "2014c" except my TCP routines have been moved into external functions
• tcpip$tcp_client_qio_2014e.bas
• tcpip$tcp_client_qio_2014e.inc
• nvt_definitions.inc
  • Same as "2014d" but with NVT support for TELNET (previously handled in TCPware by the TELNET Library)
• tcpip$tcp_client_qio_2014f_bas
  • Same as "2014e" but a bit more polished
• tcpip$tcp_sa_client_qio_basic.bas
  • stand-alone client demo (telnet to another system, log in, run a program, log out)
    this demo program works but could use a little polishing; it probably will not be developed any further
• get_host_by_name_qio.bas
  • DNS lookup from BASIC (also contains a few hacking tools)
• sff_demo.bas (caveat: SEND FROM FILE is supported by "TCPIP Services")
  • demos function tcpip$send_from_file() which is a nifty way to send SMTP messages to your own stack without opening a connection to port #25

MultiNet

1. a third-party stack from Process Software (supports IPv4 and IPv6)
2. more feature-rich than TCPIP Services for OpenVMS from HP
3. No stack-specific demos here since my "TCPIP Services" demos work with this stack

TCPware

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

• TCPware_telnet_sample.bas
  • Employs the TELNET API to demo CHARGEN, ECHO, HTTP, and TELNET. Also contains a minimal NVT handshake necessary to telnet to UNIX systems (caveat: Solaris will not let you connect unless you can provide a TERM TYPE via IAC WILL-WONT-DO-DONT; makes me wonder if this isn't some sort of simplistic anti-hacking effort)
• TCPware_pop3_demo.bas
  • Employs the TELNET API to demo connecting to a POP3 server to retrieve email
• TCPware_smtp_demo.bas
  • Employs the TELNET API to demo connecting to an SMTP server to send email
• TCPware_ftp_sample.bas
  • Employs the FTP API to demo doing FTP from within a BASIC executable

Web Demos

Apache Glue Example

• read_html_apache.com
  1. drop this DCL script into any one of your apache user-accessible scripts directories (I use "[.scripts]")
  2. rename the file to match the URL you wish to use. For example, if the link is "/demo123" then rename the file to "demo123.com"
  3. modify the script to run this next program called "read_html_apache.exe". It will read/decode the received HTML page then create DCL symbols representing the contents of HTML objects on the web page.
  4. if the program ran properly, now run your desired program which will read the DCL symbols then do whatever you want
  5. use a browser to test your application like so:
         http://node-spec/scripts/demo123
• read_html_apache.bas
  • Have the script above run this program which will:
    1. read data sent by the browser to the web server
    2. decode the HTML page
    3.  create DCL symbols representing HTML data contents of HTML objects on the web page

Apache No-Glue Example

• apache_demo.bas
  • This stand-alone application does not require any glue (DCL scripts). You could do one of the following:
    1. create a one-line DCL script which does nothing other than run your executable program
    2. drop the executable program directly into the Apache scripts directory

Password Change Demo

• www_password_change.bas
  • CGI Glue
    • can be used standalone (does not use CGI glue)
    • can be used not standalone (see Apache Glued Example above)
  • can hook into an external database (RMS in my case) to validate users
  • demos how a small amount of JavaScript (embedded in the BASIC source) can be used to pre-validate the HTML form then enabling/disabling the submit button
  • be sure to see my SYSUAF hack on this same page

Upload Demo

• coming soon
  • Got this working in production but it needs to be cleaned up before publishing
  • update: it is so ugly that you might be better off using this C function which can be called from BASIC

SOAP Demo

• axis2_soap_test_tool.bas
  • A little client-side tool used to test my SOAP services are written in C (via gSOAP) or Java (via AXIS2 running on Apache Tomcat)
  • The main program requires these three files:
    • wcsm_tcp_functions_109.fun
    • wcsm_tcp_support_109.inc
    • device_controls.inc

AJAX Demo

• coming soon
  • but here is a little taste of only the JavaScript file here: ajax_vdsl_port_mtce.js
    • AJAX (Asynchronous JavaScript and XML) is a neat, although poorly understood, client-server technology used in conjunction with DOM-compliant browsers.
    • AJAX allows a browser to fire JavaScript function XMLHttpRequest to issue an HTTP request on a secondary channel behind the current web page. More JavaScript is then employed to inject data from HTTP response into the DOM.
    • AJAX can send back ANY text document. Plain, XML, HTML, JavaScript, JSON, whatever.
    • Back in the day, I wrote many VMS-BASIC applications which employed FMS (forms management system) forms on character cell terminals like so:

      Desired Action	BASIC Code	Notes
      display a form	call fdv$disp( fname$ )
      populate a form (field-by-field)	call fdv$put( last_name$, "f$last_name" )
      populate a form (all at once)	call fdv$putal( whole_form$ )	must be a mapped string
      read a form (field-by-field)	call fdv$get( last_name$, terminator%, "f$last_name" )

Data conversion / manipulation

• caveats:
  • programmers in 2016 are still confusing UTF-8 with Unicode and this is causing huge problems
    facts:
    • UTF-8 is a Unicode encoding
    • Microsoft states that all written languages can be represented by 16-bit Unicode but this will require 3-octet UTF-8 (the spec prefers octet to byte)
    • Both MySQL and MariaDB will set aside 24-bits if you declare the data to be UTF8
    • Both MySQL and MariaDB will set aside 32-bits if you declare the data to be UTF8mb4
  • programmers in 2016 are still interchanging iso-8859-1 with cp1252 (code-page-1252 a.k.a. Windows-1252)
    facts:
    • cp1252 is a 32-character superset of iso-8859-1 so browsers treat both declarations as cp1252 (no visible errors when any of the additional 32-characters accompany a page declared to be iso-8859-1) 
    • Both MySQL and MariaDB require you to declare the character set as latin1 which is an alias for cp1252
  • some older programs below were developed in 2002 when we were attempting to translate Microsoft-generated emails -AND- incorrectly assumed we will only see 2-octet UTF-8. If you want to represent all European characters (both East and West) then you will need to support 3-octect UTF-8. It you have any contact with Asian supply chains (think Alibaba) then you will need to support 4-octet UTF-8
• Unicode and UTF-8
  • overview:
    1. When you think about it, a string is nothing more than an array of bytes. This next routine (mixed-to-unicode) assumes the input data is mixed (ASCII, ISO-8859-1, cp1252, or UTF-8) then performs a best-effort conversion into an array of 32-bit integers representing raw Unicode (you can set an option to throw away anything that doesn't appear to be legal).
    2. After that, you can call another routine to get the data you wish
  • mixed_to_unicode_array.fun
    • this external BASIC function assumes the input data contains a mixture of UTF-8 and CP1252 (which is a superset of ISO-8859-1)
      • comment: this should not happen but I have seen UTF-8 mixed with cp-1252 coming from Microsoft database engines like SQL Server
    • anything between x00 and x7F is converted to 32-bit Unicode as-is (obviously)
    • anything between x80 and xFF is assumed to be a mixture of UTF-8 and CP1252
      • everything which appears to be a valid UTF-8 sequence is converted to 32-bit Unicode
      • any remaining stuff between x80 and x9F is assumed to be CP1252 which is mapped back to equivalent 32-bit Unicode code points
      • any remaining stuff is assumed to be ISO-8859-1 and so is converted to 32-bit Unicode
  • unicode_array_to_cp1252.fun
    • also called windows-1252 (or latin1 in MySQL/MariaDB)
    • other converters:
      • unicode_array_to_ascii.fun
      • unicode_array_to_iso.fun (only convert to iso-8859-1 for use with xml; for html you should use cp1252)
  • unicode_array_to_utf8.fun
    • this external BASIC function converts from 32-bit Unicode to UTF-8
    • use this function to send mixed data to any jQuery widget which almost always requires utf-8 even though the hosting web page desires character set "windows-1252"
  • unicode_testing_bas.html
    • this demo program shows how to use the functions just described
• ebcdic_ascii.bas
  • convert EBCDIC to ASCII
• base64 conversions:

  code	description
  base64_demo_bas	this demo program invokes the next two stand-alone functions
  base64_encode_fun	function: base64 encode
  base64_decode_fun	function: base64 decode

• sort_demo.bas
  • calling VMS sort routines (sometimes it is best to defer to the experts)

Miscellaneous Stuff

Command Line

• foreign_cmd.bas
  • allows a BASIC program to read DCL command-line parameters like C programs do on UNIX

DCL symbols

• dcl_symbols.bas
  • reading DCL symbols from BASIC

DECnet Communications

• decnet_task_c.bas
  • DECnet client (start a remote server then send it some messages)
• decnet_task_s.bas
  • DECnet server (echo messages back to client)

Device Scan

• device_scan_demo.bas
  • scan some/all devices on the system

Diffie-Hellman Key Exchange Demo

• diffie_hellman_demo.bas
  • Diffie-Hellman Key Exchange Demo (limited to 64-bit math)
  • note: this happens at the start of every encrypted data transmission on the net

Displaying System errors

• display_system_error.bas
  • can translate any system error number into the associated text message. This program is no longer required since modern OpenVMS versions can do this for you from the DCL prompt.

Health Monitor

• health_check.bas
  • like a super watchdog except this program makes sure certain programs and batch jobs are present
• health_check.dat
  • sample data file

Lock Demos (CEF - Common Event Flag)

• cef_lock_demo.bas

Lock Demos (DLM - Distributed Lock Manager)

• dlm_demo_100.bas
  • creates a null lock then synchronously converts it to more restrictive forms
• dlm_demo_101.bas
  • creates a null lock then synchronously converts it to more restrictive forms
• dlm_demo_102.bas
  • asynchronously requests an exclusive lock then polls DLM to see if it was granted
• dlm_demo_103.bas
  • asynchronously requests an exclusive lock, then arms a timer, then waits for one of two event flags

Linked Lists and Memory Queues

• mem_que_demo.bas
  • demos: lib$insqhi, lib$insqti, lib$remqhi, lib$remqti but these is better done in C/C++

Mailbox Demo (Unix people use the word 'pipe')

• advocate_client.bas
  • client program to send DCL requests to a server program via a VMS mailbox; note: a VMS mailbox is similar to, but not identical to, a UNIX PIPE
• advocate_server.bas
  • server program to receive DCL requests from a client program (via a VMS mailbox)
• advocate_DCL_scripts
  • scripts to start the programs above

When you need larger DCL symbols

• multi-line_logicals_demo.bas
  • Some apps like Apache save session data (like HTTP_COOKIE) as a DCL symbol. When the data is greater than 930 bytes, Apache will save the data as multi-line logical names. This program demos how you would do something similar from BASIC
    
    Overview:
    1. all operating systems support shell variables known as symbols
    2. VMS (and OpenVMS) also support a different data-passing method known as logical names
    3. programs wishing to create or modify logical names will need to call lib$set_logical or sys$crelnm
       Caveat: lib$spawn will allow you to make changes on copied data which is discarded upon exit of that spawned task
    4. While everyone knows how to create single line logical names from BASIC, multi-line logical names are a little more difficult

Password Stuff

• password_search.bas
• be sure to see my SYSUAF hack on this same page

Peek

• peek_demo.bas
  • Unlike most other BASIC implementations, VMS-BASIC doesn't have a PEEK function but sometimes you need it
• peek_demo_test_run.bas
  • see how variables are stored in an OpenVMS system
  • see how the Alpha compiler is able to achieve such high levels of performance relative to VAX
• demo_decimal_hack.bas
  • see how fixed-point decimals are stored in OpenVMS and RMS (no difference by the way)

Population Simulation

• population_sim.bas
  • a crude human population simulation to prove/disprove some things rolling around my head. Click: sample output

System Calls you can't live without

• sys$getjpi
  • getjpi_demo.bas
    • demos how to properly call sys$getjpi (get job process information)
• sys$setddir
  • show_default_demo.bas
    • demos how a program can do the equivalent of the DCL command "$show default"
    • comment: anyone coming from RSX-11 or CP/M will remember that using SET without any parameters is the same as SHOW
• sys$getrmi
  • getrmi_demo.bas
    • demos how to properly call sys$getrmi (Resource Monitor Information)
  • getrmi_demo_mscp.bas
    • same as before except only returns mscp stuff (if mscp exists)
• sys$qio
  • qio-demo.bas
  • calling sys$qio from BASIC allows more control than PRINT and INPUT

Source Code Tools

• source_code_reporter.bas
  • generate "code change" reports (from change-area comments) to justify your existence
• source_code_formatter.bas
  • This horribly written quick-hack has proved invaluable as a tool for locating BASIC coding problems introduced by other authors.
    • Anyone who has inherited source code from another organization knows what I am typing about.
  • Caveat: I've been meaning to rewrite this tool for a decade now but can never find the time. But this tool can format itself so maybe it's good enough for occasional use

Sequencer

• sequencer.bas
  • When run from a DCL script, this program goes great lengths to ensure that your process, and only your process, gets the next number in a numerical sequence. I use this program so that an intercepted email account can temporarily access one of twenty subdirectories before I call MUNPACK to extract MIME attachments (if any) from cell phone messages. Of course, I need to run a different program to read the plain-text email if nothing was extracted

Terminal Characteristics

• terminal_characteristics_demo.bas

Timer Demos

• timer-demo-easy.bas
  • single (easy)
• timer-demo-hard.bas
  • single (hard)
• two-timer-demo.bas
  • two timers
• hiber-demo.bas
  • demos how to pause program execution without using BASIC's SLEEP statement. Supports fractional seconds
• timed_spawn.bas
  • for spawned tasks which occasionally hang, this demo will enforce a time limit

VMS Mail

• vms_mail_send_demo.bas
  • sending VMS MAIL programmatically without using DCL
• vms_mail_forward_demo.bas
  • inspecting VMS MAIL forwarding

Watchdog

• watchdog.bas
  • my own watchdog process (demos lots of systems calls)

Webification

• tool_webify_source_code.bas
  • a tool to prepare source code for display in a web page (is webification a real word?)

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

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

• wcsm_calc_easter_n_good_friday.fun
  • compute Easter or Good Friday for any date after 1582. Necessary for writing an annual holiday generator.
• wcsm_dt_stamp.fun
  • returns the current date-time in ccyymmddhhmmss format
• wcsm_get_mime_time.fun
  • mime time function for smtp use
• wcsm_get_symbol.fun
  • returns the value of a desired DCL symbol
• wcsm_peek_quad.fun
  • returns the 64-bit data work found at the specified 32-bit address
• wcsm_set_symbol_or_logical.fun
  • this function will attempt to save your data as a DCL symbol. If it can't (usually because the data is too large for your machine) then it will shift modes and save your data as multi-line logical names (emulates functionality found in the CGI interface of Apache for OpenVMS)
• wcsm_submit_to_batch.fun
  • submitting to batch from within BASIC
• wcsm_trnlnm.fun
  • translates a logical name
    caveat: we used this function in the VAX days because it was much more efficient than calling lib$get_logical and easier to set up than sys$trnlnm. But there seems to be no performance hit when using lib$get_logical on Alpha so this  function is only included here incase I've included a few demos still calling it.
• wcsm_url_decode.fun
  • undo so-called percent encoding (as well as some other stuff)

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

OpenVMS BASIC includes (file extension ".inc")

Some BASIC demos may require these standalone includes:

• vms_structures.inc
  • data structures required for item lists in system calls, etc.
• vms_externals.inc
  • system declarations required to do system calls from BASIC (should not be used for new code development)
• device_controls.inc
  • escape sequences required to embed VT terminal and LA printer inside your programs. (written for use on small VAX systems where it was not practical to control devices by system calls to the terminal driver)
• fms_fdvdef.inc
  • FMS (forms management system) definitions: functions and constants
• tcpware_ccb_definitions.inc
  • TCPware control block definitions

My BASIC Development Environment

A snapshot of my development environment. It will help you understand my how I refer to includes and standalone functions

BASIC Compiler bugs

Overview: this all started when I was trying to write a limited Diffie-Helman demo in BASIC. Why limited? I knew before I began that I wouldn't have access to the whole key space because BASIC does not natively support unsigned integers. But VMS-BASIC-1.7 does support a QUAD datatype which weighs in at 64-bits so that should have gotten me part way (a complete Diffie-Helman demo would require 512-bits, 1024-bits or more). But then I found the following problems with quad.

basic_quad_mod_bug.bas

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

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_decimal_mod_bug.bas

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

4. 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

• This affects OpenVMS-8.4 ECO 900 (a.k.a. consolidated patch kit 900 and earlier)
• In BASIC, you can use the open statement to create an indexed file with one or more keys.
• If any one of the keys is a QUAD (signed 64-bit integer) then any attempt to reopen the file will fail
• I placed a support request with HP (OpenVMS Engineering) who provided me with an experimental BASRTL 10-days later.
• Not sure if this will be released to the public so if you need it, PLACE A SUPPORT REQUEST with HP.

p.s. I was attempting to write code which would directly open SYSUAF which contains a key (a.k.a. index) based upon an unsigned quadword. 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)

BASIC bug or oversight?

I just (2020-09-03) noticed this problem with VMS BASIC-1.7 (Itanium) but with no support contract this is the only place I can complain

1000	option type=explicit
	declare string	i$	,&
		long	i%
	input "array size? ";i$
	when error in
	    i% = integer(i$)
	use
	    i% = 10
	when
2000	dim single		s(i%)
	dim double		d(i%)
	dim string		s$(i%)
	dim decimal(14,2)	de(i%)
	!
	!	use the matrix command to init these arrays
	!
3000	mat s = zer	!
	mat d = zer	!
	mat s$ = nul$	!
	mat de = zer	! this line will not compile
	!
4000	s(0) = 12.3	!

DEC-C (a.k.a. VMS-C)
DEC-C++ (a.k.a. VMS-C++ DEC-CXX , VMS-CXX)

General

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
      • http://h41379.www4.hpe.com/commercial/c/c_index.html
      • also known as DECC (Digital Equipment Corporation C)
   2. C++ on OpenVMS
      • http://h41379.www4.hpe.com/commercial/cplus/cplus_index.html
      • just what the heck is "cxx"? This is another example of Dilbert humor where the plus signs of "c++" are rotated 45 degrees. This was necessary because the VMS operating system did not allow plus signs in file names. This means that ".cpp" is also supported.
   3. DEC-C Run-Time-Library Reference Manual For OpenVMS which is used by both C and C++
      •  http://h41379.www4.hpe.com/doc/732final/5763/5763pro_001.html
      • tells you where your reference libraries are located
      • compares UNIX I/O to RMS I/O
      • introduces optional library directives which will allow UNIX-dependent c programs to run on OpenVMS
        e.g. automatically translate a full filename specification from "//one/two/three/four.txt" to "[one.two.three]four.txt"
   4. Many people today only purchase a C++ license then use it to compile C programs
   5. One definition of Sensei (a  Black Belt  in Karate) is "one who has gone before". Many times you will attempt to solve a problem which has already been solved by someone else long ago but you didn't know where to look. Some of those solutions can be seen here:
      • www.decuslib.com/freeware/freewarev40/srh_examples/ which includes lots of C sources like:
        www.decuslib.com/freeware/freewarev40/srh_examples/rms_examples.c
      • www.decuslib.com/freeware/freewarev50/srh_examples/ which includes lots of C sources like:
        www.decuslib.com/freeware/freewarev50/srh_examples/rms_examples.c
         
2. Two compilers? Many programmers claim since c++ was developed to be a superset of c then will point to numerous articles where programmers use a c++ compiler to develop better c programs. That said, I can show you examples where original developers tell third-party programmers to not use c++ compilers when building their APIs. OpenSSL is one example that springs to mind.
   • some features of c++ have been back-ported to c (using "//" to delimit comments is one obvious example)
   • however, a lot of new and interesting features added to c++ have not been back-ported to c for fear of breaking something.
   • both c and c++ compilers from HP/HPE look for these two meta data files...
     

     __DECC_INCLUDE_PROLOGUE.H
     __DECC_INCLUDE_EPILOGUE.H

     ...when loading language header files on a per directory basis. These files can modify many things including pragma statements (including case sensitivity of exported symbols) so please read chapter 1.7 of the C User's guide or chapter 9.5 of the CXX User's guide.
      
3. When calling OpenVMS routines defined in the STARLET library, do yourself a favor and enable strict type-checking. This is done by inserting this statement before the library references you wish to be strict (for new programs it should be before all library includes).

   #define __NEW_STARLET 1

   Doing so will endure 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 was forced 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 identical to an earlier relaxed version.
   
   • references: HP OpenVMS Programming Concepts Manual (http://h41379.www4.hpe.com/doc/82final/5841/5841pro_059.html )
      
4. Some large projects (especially code originally written for UNIX/Linux) may require you to build your program with a so-called "make utility". MMS (module management system) is the name of the official licensed make tool. Developers without an MMS license are advised to use MMK which is the open source freeware version available here:
   1. http://github.com/endlesssoftware/mmk
   2. http://www.decuslib.com/freeware/freewarev80/make-mmk/
   Additional Advice:
   1. many old-school VMS programmers prefer to invoke the compiler and linker from a DCL prompt. When their DCL commands become too long they will often move them into a DCL build script. While there is nothing wrong with this, older applications like "$LINK" do not support DCL symbol substitution after the "sys$input/opt" directive which then forces the developer to resort to temporary "logical names" or generating-then-executing temporary scripts. Even then, you will have some difficulty squelching a noisy link operation (lots of warnings but still a successful build). All these problems can be handled by moving to a make tool like MMK
   2. We had been using MMK-4.1 for more than a decade on Alpha with no difficulties. When we moved from Alpha to Itanium in 2014, I acquired an Itanium version of MMK-4.1 which did not always work properly with some open source offerings like mtools. Upgrading to MMK-5.0 fixed those problems
      comment: years ago, one of our developers attempted to use MMK-5.0 on Alpha but it proved problematic so we stayed with MMK-4. Do not jump to a new version of MMK unless forced to do so.  
5. GNV (Gnu Not VMS) hosts a Unix-like environment on OpenVMS: gnv.sourceforge.net
    
6. Lots of open-source software has already been ported to OpenVMS: vms-ports.sourceforge.net

C Demo Programs

C++ Demo Programs

Apache Specific (c-only)

Apache Module Authentication

Overview

• In 2014 we transitioned 100 users from green-screen to the web. Our web applications do their own authentication by hooking into SYSUAF then setting an encrypted session cookie to be used for the next hour:
  • we record every transaction and can "log out" inactive web users by deleting their specific cookie from our "current sessions" database
  • this database is also used to implement an administrative dashboard
• The negative here is that old-school access to documents stored in protected directories still require a second authentication challenge from mod_auth_openvms which cannot be checked for inactivity -AND- doesn't set a cookie. Our clients are becoming really annoyed at this.
• The success of our transition from green-screen to the web has resulted in the creation of new business opportunities resulting in ~1300 new users. However, the usual account churn has become somewhat of a burden so we would like to transition to self-serve account maintenance (think Amazon or eBay). This could done in a simple secure way if all user accounts were moved from SYSUAF to an application-level database (which is an indexed RMS file in our case). This also means that only five people (developers and sys-admins) would ever have SYSUAF accounts. Very cool!
• So I copied the password hashes of our user accounts from SYSUAF to our user profile database but still needed to keep ~100 accounts in SYSUAF to be authenticated via mod_auth_openvms. This means doing password changes in two places -AND- not allowing full self-serve account maintenance on these. (well I could but then how would I sleep at night knowing someone might stumble on a way to hack the system?)
• So we need to replace mod_auth_openvms with something more useful; something that supports session cookies

Hacks

• I started with mod_auth_openvms.c as my template but first needed to learn how to build it or there would be no point in continuing
• I downloaded a UNIX distribution of httpd-2.0.63 from Apache with the intent of only building part of it (the authorization plugins) on OpenVMS
• Then I realized APR (Apache Portable Runtime) was a prerequisite which needed to be downloaded then built separately. I wondered if this would be best done with a MAKE file under GNV or by some other method
• So I bounced the MAKE/GNV questions off people at comp.os.vms who suggested downloading CSWS sources from HP then linking against the Apache run-time which is already present (who knew?)
• CSWS source kits can be downloaded from HP's website via anonymous FTP
  • ftp://ftp.hp.com/pub/openvms/apache/ (works from IE-11)
    1. note that CSWS-V20-2 is newer and larger while CSWS-V21-1 is older and smaller (???)
    2. my examples use CSWS-V21-1 (older and smaller)
  • note: the official build instructions in chapter 5 of manual csws_install_22.pdf are broken; see my scripts below for one possible solution
• caveat: my original programs were pure hacks based upon peeking into the ".h files" included in the kit. Since then, I have learned my time could have been reduced by 80% had I first purchased a copy of Apache: The Definitive Guide published by O'Reilly. A complete list of API routines (like ap_get_basic_auth_pw) can be found in the appendix. Professional module writers may also want to check out Writing Apache Modules with Perl and C

Source Code

• mod_auth_openvms.c
  • this module was published by Compaq before the merger with HP (now HPE)
  • This 2015 production file hasn't changed since 2003-01-15 (presented here for reference purposes)
  • Comments: with the benefit of 12 years of hindsight
    • Parts appear to be derived from a Solaris program written before y2k (keep in mind that Solaris usernames are case sensitive)
    • as written, this plugin is very inefficient. It contains two hooks:
      • hook-1 will fire for every transaction "requiring Apache authentication" in the whole system whether this plugin is enabled in that directory or not. This means the hook is always fired but has been defaulted to DECLINE. When enabled, will access SYSUAF
      • hook-2 will fire for every transaction "requiring an Apache authorization" in the whole system whether this plugin is enabled in that directory or not. This means the hook is always fired but has been defaulted to DECLINE. When enabled, will search for the current USERNAME in an external GROUP FILE.
    • It might have been a better idea for Compaq to operate both routines under a single hook which would make the plugin slightly less parasitic. Alternatively, they could have published two plugin modules: "authentication only" and "authentication and authorization"
    • Another problem with the code under hook-2 is that the username test is case-sensitive. OpenVMS usernames are up-cased before going through SYSUAF authentication. This means that the GROUP FILE associated with hook-2 needs to contain both upper and lower versions of every username but someone logging in with a mixed-case username will still be bounced.  
    • the first two "c language" tests near the top of hook-1 are in the wrong order. This plugin could be made a tiny bit less parasitic if the very first line of code was the test of fUserEnable rather than a call to ap_get_basic_auth_pw (why test for a password in places where the module is disabled?)
  • my DCL build script: build_mod_auth_openvms.com
• mod_auth_vms_ext.c
  • it works with cookies, and/or username+passwords
  • it can (optionally) engage an indexed RMS-based "session cache" so the external authenticator is called less often (I do not think it would be too difficult to move this into a "global section" -- also called a shared memory object)
  • it spawns an external authenticator (which can connect to any kind of database)
  • it can command a browser to raise the username-password dialog
  • it can (optionally) command the browser to store a COOKIE (cookie data must be provided by your authenticator)
  • it can (optionally) do GROUP access restriction tests (group data must be provided by your authenticator)
  • DCL build script: build_mod_auth_vms_ext.com
• mod_auth_vms_rms.c
  • opens an indexed RMS file to perform application-level authentication (can use characters not allowed in SYSUAF)
  • essentially identical to mod_auth_vms_ext.c (above) except that lib$spawn was replaced by directly accessing an RMS-file
  • DCL build script: build_mod_auth_vms_rms.com

gSOAP Specific (c-only)

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 (a.k.a. code-first 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" which can be viewed here. This service only had three methods: ssADD, ssSubtract, and ssEcho. Then I used AXIS2 to generate a WSDL which would be used to build this gSOAP service with the same functionality.

gSOAP Specific (c++)

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

Notes:

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. VMS-C++ defaults to a file extension of ".CXX" while competing compilers default to ".CPP" so be sure to include a fully qualified file name.

Porting OpenSSL to OpenVMS

While it is possible to build OpenSSL from public sources, 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
   • see other platform examples in latest versions of s_client.c where a home-brewed function called kbhit (keyboard hit) is used to detect when the "C" program should begin a keyboard read operation in Windows
   • this is the el-cheapo solution which should be okay for s_client.c since it is not production quality code.
      
2. use a VMS-recommended technique to use a socket to connect to SYS$COMMAND
   • this solution requires a socket interface at the SSL end and a SYS$QIO at the keyboard end
   • this gold-plated solution can be seen in the program term_sock.c (terminal socket) shown just below

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.

documents:

• here is the HTML-JavaScript Code to demonstrate my AJAX-based hit counter
• here is the c-based hit counter code. It requires polishing. it also requires the addition of calls to the OpenVMS distributed lock manager (DLM) to provide better file locking than is possible with vanilla C routines for UNIX. This should be easy to do and I will publish that as soon as time permits.

Web Page Hit Counter (2.4 + 2.6)

• Muhammad Muquit is the author of a very cool multi-platform 'Hit Counter' which is currently run by many large ISPs in the world (if you don't believe me, just intercept a generated GIF then look inside where you'll see his name and URL in the comments area; his name continually flies around the internet but this is a small prices to pay for the efforts of such a gifted programmer)
•  Phil Ottewell's code to work with Process Software Corp's Purveyor 2.x Encrypt Web Server and the code is available at here).
  BTW,  I also inserted calls to the OpenVMS Distributed Lock Manager to prevent the counter data file from becoming locked out due to multiple process requiring exclusive write access.
  • If you don't believe this can happen, set up a demo web page with 20 image references to the same counter like so:
    

    <img src="http://www.your-site.org/cgi-bin/Count.cgi?dd=D&df=hack.dat&sh=1&incr=1">

  • now publish the web page to your ISP so you've got maximum CPU power and network bandwidth
  • now access the web page and watch the counters get displayed in your browser
  • now add another 10 images references and repeat the whole process. I've discovered that the counter data file will become permanently locked out by the ISP when the number of images exceeds 32 (according to www.netcraft.com one site was running Netscape-Enterprise/4.1 over Solaris while another was Microsoft-IIS/4.0 over Windows-NT4). BTW, before my patch, you would never see a permanent lockout on an OpenVMS system; just the odd counter GIF not being displayed. My Distributed Lock Manager routines make sure that every request gets honored so the odd GIF will just pop in a few milliseconds late. No big deal but that is what is so neat about OpenVMS.
• 2003-05-23: I've got a pre-release of Hit Counter v2.6 for Compaq Secure Web Server version 1.3.26 (a.k.a. CSWS, or Apache for OpenVMS) working on my AlphaServer-DS20
  

  Files	Description
  wwwcount2_4.zip	original 2.4 distribution
  wwwcount2_4p.zip	includes mods for use with WASD includes Phil's mods for use with OSU includes my mods for use with Purveyor
  wwwcount2_6.zip	original 2.6 distribution
  wwwcount2_6c.zip	my mods for use with CSWS (Apache)

Technical Observations (2013-11-xx)

• As currently implemented on OpenVMS under Apache, count.exe will produce two files. File-1 contains "the MIME header text" while file-2 contains "the binary graphic data"
• In 2013 I shifted my webserver to Ruthless Browser Caching which caused the web-counter image to stop updating (and we still need it for departmental PR)
• Since I hadn't worked on this code for ten years, I started by rewriting the DCL script to make it smaller and more efficient
• Next, I replaced the copying of file-1 (the MIME header) with output from DCL. To do this I replaced one image execution (APACHE$DCL_BIN) with another (APACHE$FLIP_CCL) which is still less expensive since we do not need to locate, then transfer, file-1.
• After that I added a second MIME line ("Cache-Control: no-cache, no-store") to deal with servers implementing Ruthless Browser Caching.
• It should be possible to modify the C sources to do away with creating intermediate files. The result would be a two-line DCL script. I publish this solution as soon as possible

  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
  $	APACHE$FLIP_CCL
  $!	write sys$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 (VMS-BASIC calling VMS-C)

All so-called "DEC languages" (VMS-COBOL, VMS-FORTRAN, VMS-Pascal, VMS-BASIC, etc) can easily pass variables (including strings and arrays) to each other. Passing variables between "DEC languages" and code written in C, C++, or MACRO is a little more difficult but not impossible.

Some BASIC solutions can be anywhere between impractical to impossible (LDAP springs to mind). Here are your options:

1. "rewrite C programs into BASIC"
   • this will be time consuming if not error prone
   • VMS does not have access to some c-language primitives like unsigned variables
2. BASIC programs could call C programs indirectly which means passing data  via "shell variables" or "logical names"
3. BASIC programs could be linked to C programs. For the last method you need to know how to pass variables back and forth

Here are some examples

• Hybrid Demo 1
  • this BASIC program basic_calling_c_demo1.bas calls C functions defined here: basic_calling_c_demo1_part2.c
  • demonstrates passing variables (long, word, byte, and VMS string) to C; one function returns a result while one does not
  • also demonstrates how C can directly access global variables declared in BASIC (ugh!)
  • caveat: the string can only be accessed in C as read only; see demo-4 below to learn how to properly modify the BASIC string from C
  • here is the DCL build script for demos 1-5: basic_calling_c_demo.com
• Hybrid Demo 2
  • this BASIC program basic_calling_c_demo2.bas calls C functions defined here: basic_calling_c_demo2_part2.c
  • demonstrates passing "arrays of longs" and "arrays of VMS strings"
  • in two instances c modifies the strings which are then displayed in BASIC
• Hybrid Demo 3
  • this BASIC program basic_calling_c_demo3.bas calls C functions defined here: basic_calling_c_demo3_part2.c
  • demonstrates how to communicate through a COMMON declared in BASIC (yep, C can read it and write it)  
• Hybrid Demo 4
  • this BASIC program basic_calling_c_demo4.bas calls a C function defined here: basic_calling_c_demo4_part2.c
  • a variable length VMS string is passed from BASIC to C where the string is extended then sent back
  • teaser: new string storage space must be allocated via str$get1_dx rather than malloc
  • hacking: write a small BASIC program which only manipulates a few strings then compile it with the "/list/machine" command-line parameters. For the most part the BASIC program will be making calls to the STR$ run-time library
• Hybrid Demo 5
  • if you have ever wondered about the differences between "passing an array by ref" vs. "passing an array by desc" then this is the demo for you.
    BTW...
    • when you pass an array by desc you are passing the address of the descriptor.
    • when you pass an array by ref you are passing the address of the array data (the receiving routine may need some additional information like array bounds, etc.)
  • this BASIC program basic_calling_c_demo5.bas calls C functions defined here: basic_calling_c_demo5_part2.c
  • in the first test, a 1-dimesion array of strings is created at run-time then passed to C (by ref) for processing
    • the C routines lengthen all strings for use by BASIC
  • in the second test, a 2-dimension array of strings is created at run-time then passed to C (by ref) for processing
    • the C routines lengthen all strings for use by BASIC
  • the third and fourth tests pass the arrays to C (by desc) so you can peek at internals (how many dimensions? what are the upper and lower bounds of each dimension? what is the striding parameter?)
  • food for thought:
    http://h30266.www3.hpe.com/odl/axplp/progtool/cpqc73/6180profile_011.html#variable_length_array_sec
• Other Hybrid Demos
  

  Title	VMS-BASIC source	VMS-C Source	Purpose	Notes
  MySQL demo 11	mysql_demo11.bas	mysql_api_demo11.c	a crude demo to prove BASIC can link to MySQL-MariaDB client routines
  MySQL demo 12	mysql_demo12.bas	mysql_api_demo12.c	c copies row results into an array
  MySQL demo 13	mysql_demo13.bas	mysql_api_demo13.c	c copies field results into a  array
  MySQL demo 14	mysql_demo14.bas	mysql_api_demo14.c	c copies field results into a VMS-BASIC multi-dimensional array
  MySQL demo 15	mysql_demo15.bas	mysql_api_demo15.c	c copies field results into a VMS-BASIC multi-dimensional array
  MySQL demo 16	mysql_demo16.bas	mysql_api_demo16.c	BASIC instructs c to change the character set c copies field results into a VMS-BASIC multi-dimensional array	okay
  mysql api 100	mysql_demo16.bas	mysql_api_100.c	derived from mysql_api_demo16.c	good
  mysql api 200	mysql_demo16.bas	mysql_api_200.c	corrects some run-time problems in mysql_api_100.c (read executive summary)	better
  mysql_demo.com			DCL build script for all MySql demos (new)
  mysql_demo1x.com			DCL build script for MySql demos 11-16 (retired)
  ssl aes demo 01 (needs polishing)	ssl_aes_demo01.bas (needs polishing)	ssl_aes_api_demo01.c (needs polishing)	encrypt BASIC string data via AES (advanced encryption standard) (needs polishing)
  ssl_aes_demo.com			DCL build script
  		base64.h	cool include file required by this demo

  Executive Summary: for mysql_demo16.bas + mysql_api_200.c:
  (1) Suppose you needed to open a table that would return 35 fields with a maximum of 500 records. Just create a 2-dimensional array of size 500 x 35 in BASIC, then copy the array details into a common, then call the routines defined in "mysql_api_200.c". That c program will make the call to the database, then will parse the results, then will update the 2-dimensional array. When you exit back to BASIC, the array will already be sitting there ready to be processed in any way you wish.
  (2) this program allows you to have up to 10 tables open at once.

Java and AXIS2 Web Services

• click here for tips on how to deploy these web services in AXIS2
• click here for Java or Tomcat issues
• click here for a AXIS2 test tool written in VMS-BASIC

OpenVMS DCL scripts

caveat: the ".com" file extension in VMS/OpenVMS predates MS-DOS and MS-Windows. Here it means "commands" 

OpenVMS Macro32 source code

OpenVMS Programming

Introduction to OpenVMS programming

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  

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

• The first thing Compaq did was to convert the 32-binder Gray Wall (with a single CD-ROM.  GOOD  This allowed them to shut down their document publishing business)
   
• Next, they put all their OpenVMS documents online so that anyone could access them for free.  GOOD 
   
• Next, they shut down their educational services division to save money.  BAD  Technically speaking, they didn't just shut it down cold, they attempted to pass the business to third-party educators like they did with their PC products. But the scheme flopped. (hey, what would you expect from a shoot-from-the-hip PC company?)

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.

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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 VMS-BASIC and VMS-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 www.bookfinder.com 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

• OpenVMS On-line Documentation HTML + PDF
  • Operating System Docs
    • OpenVMS-8.4 docs + manuals
    • HP OpenVMS UNIX Portability Initiative (Apache is proof)
  • (some) Language Manuals
    • introduced in 1980 by DEC as BASIC Multikey ISAM)
    • HP C for OpenVMS
      • Enabling C RTL Features Using Feature Logical Names
        http://h41379.www4.hpe.com/doc/83final/5763/5763pro_004.html
    • HP C++ for OpenVMS
    • HP COBOL for OpenVMS
    • HP FORTRAN for OpenVMS
    • HP Pascal for OpenVMS
  • Miscellaneous Stuff
    • Archived Manuals (DECnet for example)
    • Secure Web Server (a.k.a. Apache for OpenVMS)
    • HP FMS for OpenVMS - I64
    • HP FMS for OpenVMS - VAX/AXP
      • 6 Forms Management System manuals including:
        • Introduction to VAX-11 FMS
        • FMS Language Interface Manual
        • FMS Utilities Reference Manual
        • FMS Form Driver Reference Manual
• Hoff's OpenVMS FAQ (at Hoffman's Labs)
  • OpenVMS FAQ - DCL Details
• HP OpenVMS Technical Journal
• OpenVMS Release History (version 4.0 to present)
• MACRO Programming
  • https://hunter.goatley.com/macro-made-easy/

Advanced hacking (system services)

Many programmers do not know about this technique to trace "system service calls" originating from your process (DCL or otherwise). So if you have the necessary privs, and are on an Alpha or Itanium, then try this experiment:

Legend:
	<sr> = system response
	<ur> = user response
--------------------------------------------------------
<sr> $							! this is my DCL prompt
<ur> set process /sslog=(state=on,count=4,flag=arg)	! enable tracing on YOUR process
<sr> $
<ur> run your-program.exe
<sr> ...run the program then exit...
     $
<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> $
<ur> type/page ss_trace.txt

Official Documents:

• Chapter 14 System Service Logging
  http://h41379.www4.hpe.com/doc/84final/6549/6549pro_sslog.html#sys_svc_logging
• comment: on Linux you use the command strace which is a lot less complicated by comparison

Noteworthy C/C++ demos at other sites

• eight-cubed.com - Programming Examples very high quality "C" demos for OpenVMS
• "Intro to C" (C programming from a DEC-C and VAX-C perspective) from Phil Ottewell
  alternate source: https://web.archive.org/web/20131206110138/http://pottsoft.com/c_course/course.html (via the WayBack Machine)
• C++ STL Tutorial from Phil Ottewell
  alternate source: https://web.archive.org/web/20131206104013/http://pottsoft.com/stl/stl.htmlx (via the WayBack Machine) 
• visit http://www.codecogs.com/

Noteworthy C/C++ articles and manuals

• C Traps and Pitfalls - Andrew Koenig - AT&T Bell Laboratories
  • http://www.literateprogramming.com/ctraps.pdf
  • quote: The C language is like a carving knife: simple, sharp, and extremely useful in skilled hands. Like any sharp tool, C can injure people who don’t know how to handle it. This paper shows some of the ways C can injure the unwary, and how to avoid injury.
• DEC-C Run-Time Library Reference Manual for OpenVMS
  http://h41379.www4.hpe.com/doc/84final/5763/5763profile.html
  • Enabling C RTL Features Using Feature Logical Names
    http://h41379.www4.hpe.com/doc/83final/5763/5763pro_004.html
  • C RTL Feature Logical Names
    http://h41379.www4.hpe.com/doc/83final/5763/5763pro_004.html#feature_logical_tab
    • DECC$UNIX_LEVEL 90
    • DECC$SELECT_IGNORES_INVALID_FD
    • DECC$UMASK
    • DECC$POSIX_COMPLIANT_PATHNAMES
• UNIX, Linux to OpenVMS Porting Guidelines
  http://h41379.www4.hpe.com/portability/portingguidelines.html
  quote: Select() call is extensively used in UNIX variants for asynchronous I/O and to handle I/O from multiple descriptors at the same time. However in OpenVMS Select() call does not manage the file descriptors and manages only the socket descriptors for remote communication. You can handle this limitation in OpenVMS using the QIO and AST mechanism.
• HP TCP/IP Services for OpenVMS Sockets API and System Services Programming
  http://h41379.www4.hpe.com/doc/82final/6529/6529pro.html

How to recover from FTP-induced saveset corruption

$set file /attr=(RFM:FIX,MRS:512,LRL=512,ORG=SEQ,RAT=NONE)	yourfile.sav

Note: this will also be required if you zip your backup saveset files to reduce storage space. After you unzip the file, $BACKUP will not be able to access the contents until you invoke this magic incantation. Perhaps we should call this ZIP-induced saveset corruption :-)

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Neil Rieck
Waterloo, Ontario, Canada.