Category:Debugger Home

From m204wiki
Jump to navigation Jump to search

This is a master category and page for all things Debugger (Janus/TN3270 Sirius Debugger). It is currently under construction, so it is subject to changes and formatting.

About the Debuggers

The Janus Debugger is a tool designed for developers who create and maintain Janus Web Server applications. With software installed in the Model 204 Online, as well as on a workstation with a browser that can access the Web Server, the Janus Debugger lets you examine in statement by statement detail the SOUL code that the Web Server executes.

The TN3270 Debugger is designed for developers who create and maintain Model 204 3270 and Batch2 applications. With software installed on the Model 204 Online, it uses the same Debugger Client as the Janus Debugger, letting you examine 3270 and Batch2 applications.

An instance of the Debugger Client can be debugging a web application (acting as the Janus Debugger), or it can be debugging a 3270 or Batch2 application (acting as the TN3270 Debugger). At any given time, it may only be debugging one type of application. The title bar of the Debugger Client indicates the application type.

The basic operation

When you are running under the Janus Debugger, and Janus Web Server is about to run a request on your behalf, or you are running under the TN3270 Debugger, and you run a 3270 or Batch2 request:

  1. Request source code is sent to the Debugger Client deployed on a workstation.
  2. The Debugger Client displays the code, navigable to top and bottom, with search features available.
  3. Program execution is paused, the Debugger awaiting the instructions you provide through the Client GUI.

The feature set

Both Debuggers provide these typical debugging capabilities:

  • Viewing code while running it
  • Stepping through the code one statement at a time
  • Examining variable values
  • Using a separate "watch window" for the display of specified data items
  • Setting breakpoints at which code execution pauses
  • Skipping over selected subroutines/methods

In addition, the Debuggers provide:

  • A compact Graphical User Interface with user configurable buttons and hot keys
  • Views of the Model 204 audit trail and code executed by daemons
  • Tracing of statements that modify variables in executed code lines, or tracing until a variable becomes a certain value
  • Saving of sets of variables to be watched, which are restorable at any time
  • Display of Web Server output (Janus Debugger) and screen variables (TN3270 Debugger)
  • A code line's Model 204 procedure details (subsystem, file, name, line number, text preceding dummy string substitution)
  • Filtering of program code to skip over all but the Model 204 procedure you identify or the procedures you selected (added to "White List")
  • Stepping out of a called subroutine, method, or daemon and continuing processing at the statement after the call to the subroutine, method, or daemon
  • Examination of longstrings, $lists, objects
  • System class methods that let you insert code in User Language that runs only under the Debuggers

The architecture

The following figure displays the principal components in a Janus Debugger configuration:


The main components in a TN3270 Debugger configuration parallel those in the Janus Debugger configuration, the principal exception being the absence of the web browser:


Per Debugger session for a Janus Web or 3270 or Batch2 application, these components are active in the Online and on the workstation:

Model 204 nucleus hooks

(Assembler; not shown above)


  • Capture source lines, before and after dummy string substitution.
  • Note source of line (procedure and file).


  • Can step one statement at a time, and can step over routines and methods.
  • Can stop on breakpoints.
  • Between statements, can get variable, field, and global values, to support display, trace, watch, etc.
Janus Web thread Janus Debugger only.
3270/Batch2 thread TN3270 Debugger only.

Worker threads

(Assembler Language, one for each thread being debugged)

For each debugging session, a “worker thread” arbitrates between the thread being debugged and the workstation client.

A worker thread does the following:

  • Passes data between the thread being debugged and the Client.
  • Controls the execution of the thread being debugged, at the behest of the Client.

Debugger Client

(Windows GUI, written in VB.NET)

The Debugger Client resides on the developer's workstation. It is a proxy server in a Janus Debugger session: the browser no longer directly connects to the Web Server, but instead it "sends" to and "receives" from the Client.

The Client GUI lets you control the application and view variable values, source code, traces, and for Janus Debugger sessions, the web output buffer.

Web browser Janus Debugger only. Any web browser that allows proxy servers.

Versions and builds 

Independent of the version of Model 204 being run, the Debugger Client has its own numbered sequence of "builds" that contain new and updated features. From build to build of the Debugger Client, the About box (accessed by the Help menu) provides a searchable list of the principal changes in each of the previous builds of the Debugger Client.

System requirements

The Online Configuration section of this document specifies the requirements for Model 204 product release levels, licenses, and maintenance, as well as Debugger product authorization. In addition are instructions for configuring a Model 204 Online that hosts the Debugger, which include User 0 parameter and TCP port definitions and increases in storage table and work area sizes for both of these:

  • The worker thread that services a debugging session
  • The thread on which the program to be debugged is running  

Known limitations 

The following are known limitations and issues concerning the Janus and TN3270 Debuggers:

  • You may not use either Debugger for DBCS data.  
  • You may use the Janus Debugger on a Janus Web Legacy Support thread only if you also have a license for the TN3270 Debugger.
  • No asynchronous daemon or $COMMBG requests may be debugged. They are simply ignored by the Debugger (and they execute normally).
  • The client requires Windows 7 or higher.
  • Both the Execution Trace tab (output from one trace) and the Web Buffer tab have 5000 line capacities. If the capacity is exceeded, the last 5000 lines are shown.

Check Prerequisites

Ensure you are running Version 7.5 or higher of Model 204.  You can verify this by issuing the VIEW VERSION command at the Model 204 command prompt, for example:

VIEW VERSION                                   VERSION   7.9.0A      Release of Model 204 

Installation and Configuration

This section describes how to install the Janus Debugger, the TN3270 Debugger, or both. Once you complete this installation, you can begin to use either or both products.

This section consists of two subsections of mostly cookbook-style directions. You should first complete the steps in the "Online Configuration" section, then complete  the "Workstation Configuration" section.

Most of the steps are to be performed whether you are installing one or both Debugger products, and exceptions are noted.

If you will be using a local editor (Xtend or UltraEdit) with the Debugger, finish the Debugger installation first, then see Using a local editor.

For information about setting up at your site a centralized distribution of updated Debugger Client replacement files, see Providing updated versions of the Debugger Client.

Online Configuration

This section shows how to prepare a Model 204 Online for use of the Janus Debugger, the TN3270 Debugger, or both.

The installation tasks require Model 204 system manager privileges. Also, since you must set at least one User 0 parameter, a cycle of the Model 204 Online will be required.

The Online configuration tasks are listed below.


&&amDaemonReturns a 1 if a Daemon tab contains the currently active code. Otherwise, the returned number is 0.
&&argServes as a placeholder for a command argument within a macro (if used outside of a macro, an error is issued).
&&assertFailureCountReturns a count of the number of times that the result of an assert command is a Failure.
&&assertStatusReturns a string that contains a summary of the counts of assert command results.
&&assertSuccessCountReturns a count of the number of times that the result of an assert macro command is a Success.
&&blackOrWhiteListTests whether the Debugger is filtering the procedures you are going to debug, and if so, whether a Black List or White List is being used.
&&buildNumberReturns the number of the build of the Client from which the function is called.
&&concatenateConcatenate and return the function's arguments.
&&currentPacFileReturns the URL of the Proxy Auto Config (PAC) file in use, or it returns empty if no PAC file is in use.
&&currentRunningMacroReturns the full file-system path to the macro within which it is called. If not called from within a macro, the function returns a null string.
&&currentTitleReturns the current title of the Client main window.
&&existsTests if a macro variable is defined.
&&fileExistsReturns 1 if the file identified by fileSpec exists, 0 if not.
&&getMainSearchInputAreaReturns the value specified in the search input area on the Client main window.
&&getScopeReturns the scope of the specified routine from the SOUL call stack, -1 if routine not found or we are not executing a program.
&&globalAssertFailureCountSame as &&assertFailureCount except its scope is the entire Client session.
&&globalAssertStatusSame as &&assertStatus except its scope is the entire Client session.
&&globalAssertSuccessCountSame as &&assertSuccessCount except its scope is the entire Client session.
&&ieMode functionReturns the current setting of the Client's IE Mode preference.
&&indexReturns the 1-based position of the needle argument within the haystack argument, or it returns 0 if the needle value is not found within the haystack value.
&&isWatchedDetermines whether its argument is a variable that is currently specified in the Watch Window. If it is, &&isWatched returns 1<; if not, it returns 0.
&&isWindowOpenReturns 1 if the window whose title is passed is open, 0 otherwise
&&lengthReturns the length in characters of its string argument.
&&logFileReturns the absolute Windows file path of the client log file (the log.txt file).
&&numberOfBreakpointsReturns the number of breakpoints that are set in the current request, irrespective of the current executing position in the request.
&&numberOfLevelsReturns the number of code levels being debugged. The main program is one level, and each active daemon adds another level.
&&numberWatchedReturns the number of items that are currently being watched in the Watch Window.
&&originalTitleReturns the default value of the title of the Client main window.
&&preferenceReturns the value of the specified Client preference setting.
&&procNameReturns the name of the procedure that is being executed.
&&promptPauses a macro while you supply an argument value for a command that is specified within the macro, then continues running the macro using the supplied value for the command.
&&quoteReturns its argument enclosed in double quotes.
&&scriptFolderReturns the value of <scriptFolder> from debuggerConfig.xml.
&&searchResultReturns the line number of the line that contained the found string, if the last Client search operation successfully found something.
&&searchSuccessReturns 1 (True) if the last Client search operation (invoked by button or command) successfully found something. If the last search found nothing, or if there was no prior search, &&searchSuccess returns 0 (False).
&&selectedTabReturns the label of the Client main window tab that is currently active. Or, it returns a null string () if no tab is active
&&stateFileFolderReturns the location of all "state" files such as the log and saved preferences and window positions.
&&statusMessageReturns the most recent Client status message.
&&substringReturn a substring of the target string argument.
&&sumReturns the sum of the function arguments.
&&verifyMatchReturns the 1-based position (in string) of the first character in string that is also in the characters in charSet.
&&verifyNoMatchReturns the 1-based position (in string) of the first character in string that is not in the characters in charSet. If no character in string is not in charSet, returns 0.
&&windowStatusReturns 1 if the named window is open, 0 otherwise.


This category has only the following subcategory.

Pages in category "Debugger Home"

The following 108 pages are in this category, out of 108 total.