
                ObjectVision 2.0 Trace Facility 
                -------------------------------

ObjectVision 2.0 has an undocumented feature that allows you to trace
events during execution of an application for debugging purposes.  Each
event that occurs to each object is logged to a file or a device (such
as an AUX monitor).

 
To use the feature, you must edit your WIN.INI file, and in the
ObjectVision section add the following lines:

EnableAuxPrintf=Yes 
AuxName=<file or device name>        [Note]
TraceEvents=1 
TraceObjects=1

Note: 
------- 
If this line is absent, trace listing goes to device AUX.  If a file
path name is specified, the file MUST EXIST and TRACE will overwrite
existing records. So, if you plan to trace to a file, it is recommended
that you erase the contents of the file (but not the file itself) before
beginning.

------------------------------------------------------ 
One way to implement this feature is to add 2 EMPTY files to the
\VISION directory:

        EMPTY.TXT 
        TRACE.TXT

  
Edit the ObjectVision section of WIN.INI as follows:

        EnableAuxPrintf=Yes 
        AuxName=\VISION\TRACE.TXT 
        TraceEvents=1 
        TraceObjects=1

Add 2 Icons to the OV group:

1)      Name: RESET TRACE   
        Property: XCOPY \VISION\EMPTY.TXT \VISION\TRACE.TXT

2)      Name: OV TRACE 
        Property: NOTEPAD.EXE \VISION\TRACE.TXT

To use it: 

1) 2-click RESET TRACE to clear the contents of TRACE.TXT.  (NOTE: OV
MUST NOT BE RUNNING.)

 
2) Open the OV app, begin debugging.

3) Use OV TRACE to view the contents of the TRACE.TXT file.  This can be
done while OV is running, however, it does not refresh as new records
are added, so you need to close NOTEPAD and relaunch it, or simply
reopen the file.

______________________________________________________

This will create a text file called TRACE.TXT.  TRACE.TXT will
contain information about the events that occur in an
ObjectVision session.  The contents of this file are, for the
most part, self explanatory, following the format <Event> <Type
of object> <Object name>.  For example, if a click event happened
on a button called Button1, it would display like this:

Click Field Button1.

Caution!  It is not recommended that this configuration be kept
permanently.  The file that is written to can become very large
if not closely watched.  To turn off tracing, mofify WIN.INI to 
be:

        EnableAuxprintf=No

If you have an auxiliary monochrome monitor, the AuxName can be
replaced by "AuxName=Aux".  This will print the display to this
monitor.  It must be pointed out that this monitor must be the
correct type, a text based monochrome monitor, and it must be set
up correctly, with the appropriate video drivers.  Check with the
manufacturer of the monitor for information on setting it up as
an auxiliary monitor.
____________________________________________________________

NOTES: 
----- 
1) If you don't clear the contents of TRACE.TXT, opening a new OV app
will reset the file pointer, but not clear the contents, so records will
be overwritten from the beginning of the file.  In this case, it may be
difficult to see where the trace stops!

2) Once WIN.INI is modified, it is not necessary to restart Windows.  As
OV is launched, it fetches the WIN.INI settings from the file.

3) See WINAUX.TXT for information on sending the output to a Window using
WINAUX.SYS  
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