tuple creation in C extensions

[Louis M. Pecora]

>On Wed, Jun 14, 2000 at 11:16:50AM +0000, Louis M. Pecora wrote:
>
>> > Wow, thanks for looking that code over, Bernhard.  What a horrible
bunch
>> > of holes.
>
>> And who could have seen all that so clearly without an expert on
hand. 
>> Even then I couldn't understand all the reasoning.  In Python we are
all
>> happy, but the ugly side is when we return to C.  It's obvious to me:
>
>> CAN'T SOMEONE UPDATE THE EXTENSIONS PDF MANUAL, ADDING A BETTER
TUTORIAL
>> ON REFERENCE COUNTS AND (!!) LISTING Py_XXXX FUNCTIONS AND THEIR
REFERENCE
>> EFFECTS ??
>
>Sure, anyone can. The address to submit your new sections is
>python-docs at python.org, I believe. Note that you shouldn't send in PDF
>documents. The actual documentation is written in TeX, which is used to
>generate PostScript, PDF, HTML, info and what not. I'm sure someone
will
>volunteer to rewrite your plaintext-version to TeX if you write a good
>manual on reference counts ;-)

The old "give the assignment to the guy who complains the most," eh? 
:-) 

Of course, if I knew all that, I wouldn't complain.  

>> Sorry to yell, but it's obvious that many people like me are
stumbling
>> with this one.  I'd hate to have all that time I save using Python
eaten
>> up by debugging C extensions.
>
>The API interface documentation is pretty clear in which functions
give or
>take a reference. *most* functions do not touch references, they take
the
>object you give to them, do their thing, and return a result. Those
that
>return objects are documented as returning either a new reference or a
>borrowed reference (in which case, if you keep the object around, you
have
>to INCREF yourself) and those that steal a reference (take an Object
>argument without returning it, and without INCREFing it) are
documented to
>do so as well.

Maybe I missed something in the documentation - -and I will go back and
check it out--but I don't remember seeing a list of functions which
said whether INC- or DECREF's were necessary with it.  There were some
examples, but there are a lot of functions in the Python library, it
seems, that are not mentioned.  

>The only trouble I had with refcounting (while writing the
>augmented_assignment patch) was not bothering to see wether
PyDict_SetItem()
>stole a reference or not. It doesn't, but I did INCREF, so I was
leaking ;-P

OK, good example. How _did_ you find out what your problem was and what
was _really_ required by PyDict_SetItem()?  Did you have to dig into
the actual code for  PyDict_SetItem()?