[Lintouch-announce] Lintouch Development Weekly News - February 15th, 2004

[Martin Man]

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Lintouch Development Weekly News
http://lintouch.org
February 15th, 2004
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Welcome to the eighth issue of the Lintouch Development Weekly Newsletter
codenamed "Getting closer guys..."

After fourteen days since the last issue lot of things has changed. Namely
Lintouch Server is not deadlocking anymore, thus being much more usable then
before the freeze, Lintouch Runtime does not leak memory and does not crash
(or has not crashed for a rather long time). More detailed stories follow.

Jiri did the investigation and figured out that integration of Python and C
code in a multi-threaded application is not so straightforward as we thought.
One of the deadlock reasons was the _Global Interpreter Lock_ thing (which
protects the python interpreter from being corrupted by C extensions which
somehow interact with threading and scheduler) that we were not unlocking in
our code. Detailed explanation can be found in his email[1]. Another reason
of deadlocking was a completely wrong locking scenario which was so wrong,
that it could have bee used as an example at university in first lessons of
concurrent programming. Fortunately the solution has been found, implemented
and till now seems to be working correctly[2].

    1. http://lintouch.org/pipermail/lintouch-dev/2004-February/000382.html
    2. http://lintouch.org/pipermail/lintouch-dev/2004-February/000389.html

At the Runtime front, all segfaults have hopefully been hunted by simply
walking through code and deeply thinking about every FIXME: statement that
was there. Some of the bugs were more than spicy and I must say all have
been related to memory management: Dangling Pointers(tm)
and Unfreed Memory et al. Thanx goes to all team members for spending
sleepless nights with gdb (The GNU Debugger).

Now we are basically going through the TODO lists for every library and
preparing everything for release. At this moment the following libraries are
prepared for 1.0 release:

    - libwtngio
    - libwtngfsm
    - libwtngvars
    - libwtngzip
    - libwtngvfs
    - libwtnglocalizator
    - libwtngpanel
    - libwtngproject
    - libwtngtemplates

The rest is going through final polishing, Runtime needs all dialogs,
messages and layouts to be finalized. Server is 99% ready, Python WTNG
Bindings might be enhanced a little bit but need not to at this moment, the
same applies for the rest of libraries:

    - libwtngcp
    - python-wtng
    - server
    - runtime

And to make you hot and looking forward to a release, I've prepared one
little screenshot[3] showing Server running and serving two Runtimes which
display the same panel with a row of buttons and row of lamps bound to the
same server variables. Notice how button pressed in the first runtime loops
back the bit to the lamp just bellow it and how the change is reflected by
both Runtimes. This is possible thanx to the simple Loopback plugin which is
included with the server by default to ease testing.

    3. http://www.swac.cz/~mman/lintouch-0.90.png

That's all folks for this week, if you have any comments, corrections or
ideas to be published, feel free to contact me directly[0].

    0. mailto:mman at swac.cz.

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