Am 26.04.2011 16:03, schrieb Hegedüs Ervin:
I've read API doc (which you've included in another mail), but
that's not clear for me. :(
No probem, I'll go in detail, now as I have read it again. (I didn't
want to help from memory, as it is some time ago I worked with it, and
didn't have time to read it.)
The most critical parts are indeed
* the input parameters
The ownership rules say that the input parameter belongs to the caller
who holds it at least until we return. (We just "borrow" it.) So no
action needed.
* Py_BuildValue()
This function "transfers ownership", as it is none of
(PyTuple_GetItem(), PyList_GetItem(), PyDict_GetItem(),
PyDict_GetItemString()).
So the value it returns belongs to us, for now.
We do transfer ownership to our caller (implicitly), so no action is
required as well here.
so, it means when I implicit allocate a new object (whit
Py_BuildValue()), Python's GC will free that pointer when it
doesn't require anymore?
In a way, yes. But you have to obey ownership: whom belongs the current
reference? If it is not ours, and we need it, we do Py_(X)INCREF(). If
we got it, but don't need it, we do Py_(X)DECREF().
BTW: Is there any reason for using calloc()? malloc() would probably
be faster...
may be, I didn't measure it ever... but calloc() gives clear
space... :)
Ok. (But as sizeof(char) is, by C standard definition, always 1, you can
write it shorter.)
Thomas
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