python wrapper question

Christopher T King squirrel at WPI.EDU
Tue Jul 27 16:33:24 CEST 2004


On Mon, 26 Jul 2004, Garett Shulman wrote:

> Hello, I am trying to create a wrapper for a function with the following 
> prototype:
> int ap_get_playlist(int session, int *argc, char ***the_list);
> I'm not quite sure how to construct the Py_BuildValue. I would like the 
> python function to return a list of strings. However, the length of the 
> list, (*argc in the function call), will vary at run time. Is it 
> possible to have a wrapper function return a list whose size is not know 
> at compile time? Thanks for any suggestions. -Garett

You will have to construct the list manually, using PyList_New(argc) to
make a new list of the correct size, PyString_FromString(...) for each
item to make a string out of it, and PyList_SET_ITEM(...) to store each 
item into the list.  You can then pass the resulting list to Py_BuildValue 
as an "O" type.

Alternatively, you can wrap the above list-building goo in a function 
that accepts a char ** and returns a PyObject *, and then use the magic 
"O&" type in Py_BuildValue, passing it first your list-building function 
and then the string array.

Hope this all made some sense :P




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