SYS21 - Re: SYS21 - Magic Numbers

Look inside the source of any standard DSPF in the JBA package and you should
find a section of code that looks like this:
0032.00 %%%A%A* Following record format ID added by ADDDSPFRID command
951018
0033.00 %%%A%A                                  2  2'*++AI001'
951018
0034.00 %%%A%A                                      DSPATR(ND)
951018

The '*++AI001' bit is the "magic number"...

It is a field in each screen format that is non-displayed.  The purpose of the
field is to make the display format uniquely identifiable within the 5250
emulation data stream.

This concept was introduced into the JBA package back in the mid 1990s to allow
for the use of screen designer type gui applications where you could customize
the appearance of particular screens on your own PC...

The way the PC gui application recognized that there was a custom copy of a
screen that it should display was when the magic number in the 5250 emulation
data stream was detected and it matched a modified screen on that PC...  The
custom screen would be displayed instead of the standard screen...  So you see -
every screen display format had to have its own unique identifier...

JBA undertook a massive project to add display file record IDs to every DSPF and
in the process developed the command ADDDSPFRID.  Which can still be foound
today in the IPGAGP3 or IPGCFP4 library...

And that's just about all I know about the "magic numbers" in JBA...

For the most part if you don't do any gui screen mods with screen designer you
can pretty much ignore the magic numbers...
Just know that they are there, usually in position 2,2 of every screen and if
you're making a mod to a screen you might bump into one...

Hope that helps...








Brian.True@trelleborg.com on 05/21/2002 02:39:34 PM

Please respond to jbausers-l@midrange.com



  To:          jbausers-l@midrange.com

  cc:          (bcc: Jeff Klipa/Harvard)



  Subject      SYS21 -  Magic Numbers
  :







We are getting ready to install SP4 and  I have been going through the
documentation.  "MAGIC" numbers references keep popping up. For my own
curiosity, what are they talking about?

Thanks

Brian True
Trelleborg Automotive
Software Support Technician
South Haven, MI
(616) 639-4249


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