using strings from extension module question + possible documentation error

[Oleg Leschov]

Hi,

I am writing an extension module in which I want to do some heavy
number crunching on large amount of data.

The input data is prepared using Python code and passed to this
extension module via strings containing binary data, and the result is
also passed back as a list of pretty large strings containing binary
data.

So first I thought I'll just pass the empty strings made in Python
along with input data strings, so my extension code would just fill
those empty strings with the results.

But then I read the PyString docs, it says I must not modify any
strings even though it seems to be possible...

Ok then I decided I'll create a list and fill it with strings from my
C extension code..

However to avoid data copying I wish to fill the newly created (using
PyString_FromString(NULL,x) ) strings' buffers (obtained with
PyString_AsString) with data after creating them in my extension
module.

The question is - is this allowed? Because the doc says this
> The data must not be modified in any way, unless the string was just created using PyString_FromStringAndSize(NULL, size).

but what exactly does "just created" mean? will it not be considered
"just created" if I call any more Python stuff after
PyString_FromString, like another PyString_FromString along with
PyString_AsString? Which I certainly intend to do since I first create
all strings I want, and then do my calculations which fill those with
actual data.


Another question is this - why does PyString_AsString doc states that
> Return a NUL-terminated representation of the contents of string.

when strings may contain binary data and thus NOT NUL-terminated in
general? is this a documentation error or I can't access binary
strings using PyString_AsString ?

P.S. the doc quotes are from
http://docs.python.org/release/2.6.6/c-api/string.html