Re: Upgrade from 3.6

[David Foster <foster(at)bial1.ucsd.edu>]

Jay E Cable wrote:
> 
> Hi,
> I am looking into how much work is involved in upgrading idl.  Currently
> we are using a 3.6 on a osf alpha, and would like to upgrade to the
> latest version of idl.  If anyone has gone though this before, and has
> any advice or suggestions about how much w ork is involved, I would really
> apreachate it.  We are using idl for the gui of a large software system,
> so the main interest is in how much the widgets and what not have changed.
> Thanks!
>                 -Jay
>                 ftjec@uaf.edu

Well, I would strongly recommend upgrading, as there are many new
features that make it well worth the effort. One of the nicest
features it the ability to have your IDL prompt come back after you
start a program, which allows you to have multiple programs up at
the same time.

As far as the amount of work it takes, consider this. When we upgraded
to IDL 5.0, *every* single widget application we had no longer worked!
This sounds terrible, but it really wasn't that much trouble to get
things working again. Most of the changes involved moving the /MODAL
keyword from XMANAGER to the TLB WIDGET_BASE call, and changes to
the XMANAGER call (including the keyword /NO_BLOCK for apps that
don't block events, so XMANAGER returns immediately after registering
the app, and you get your IDL command-line back).

There were some minor changes in the requirements for GROUP_LEADER
keyword for modal widgets. Also, the concept of "modal" widgets became
more rigorous.

Plan to spend some time getting widget apps to work under 5.X; it's
worth the trouble. Liam's suggestion to get a demo is a great idea;
take one application and try to convert it. If you have questions
feel free to call/email me and I'll be glad to help you out.

Dave
-- 

  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    David S. Foster         Univ. of California, San Diego
     Programmer/Analyst     Brain Image Analysis Laboratory
     foster@bial1.ucsd.edu  Department of Psychiatry
     (619) 622-5892         8950 Via La Jolla Drive, Suite 2240
                            La Jolla, CA  92037
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