[C++-sig] Am I crazy or is it my computer?
s_sourceforge at nedprod.com
Thu Nov 1 21:58:00 CET 2007
On 31 Oct 2007 at 15:11, Matthew Scouten wrote:
> Ok, I just found this:
> I seems to be saying that I can not do what I want with out patching
> Boost::Python (or does this only apply to multiple interpretors? )
> Is this still true (please tell me it's been fixed)?
> if so, where can I get this patch and how do I apply it?
Follow the link to TnFOX given in the FAQ. Then study FXPython -
heavily - and with a very fine toothed comb.
> I asked about multi-threading and boost python in on this list a while ago,
> and got no answer. I took this a a "go ahead, no problems". If I am being an
> idiot, could you tell me so? Just flame away at me so I know I've been
I remember your question, and I didn't answer because the FAQ answers
and I don't have the time to answer FAQ answered questions. I think
the Boost.Python homepage could do with a large flashing neon sign
saying "CHECK THE FAQ BEFORE ASKING A QUESTION" right before "SEARCH
THE C++ SIG MAILING LIST ARCHIVES BEFORE ASKING A QUESTION".
Had you done either, you would have known the answer.
Now with the berating being done, I must express my sympathies for
your task. I wrapped TnFOX for Python using Boost.Python and it was
extremely painful indeed. It can be done, but expect at least 200
hours of programmer time to wrap your head around it. Once you know
what you're doing, it becomes quite easy.
> A lot of people here actually know what they are doing. I do not
> have that luxury. I am finding boost python extremely complex and
> non-intuitive. There is also a lack of good documentation (example code is
> nice to have, but does not constitute proper documentation all by itself).
Actually, the docs are pretty good. I would have cut out my own
tongue to admit that a few years ago, but the problem is not the
documentation - it's the programmer thinking in old style C++ ways.
Once you wrap your head around Boost.Python, it becomes quite
intuitive. I can now happilly plug around its internals and do
anything I like fairly confidently. It's actually quite a simple &
intuitive design though I do wish there were more usage examples out
there - and also I wish more interfaces were publicly defined &
Now I have designed the machinery needed to get threaded C++ and
Python working. It took me months, and it's not pretty at all and
rather easy to break if you modify it. But copying me would be the
easiest by far.
BTW I reckon your problems stem from the GIL not only being a lock
but also being a state variable for Python. This state varies,
unpredictably, during and between locks whenever you touch Python at
all (including via any other thread). Touching BPL in any way usually
means touching Python, so basically dragons abound here.
This will explain the often erratic & weird ordering of actions in
FXPython in TnFOX - I worked it out after many hours in the debugger
watching Python, C++, and Boost.Python interact. I suggest you copy
my form closely in your endeavours.
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