reference counting and PyTuple_SetItem
tim.one at comcast.net
Thu Jun 10 19:50:20 CEST 2004
> while (<some condition>)
> pyRHost = PyString_FromString(rHost);
You now own a reference to pyRHost.
> Py_INCREF(pyRHost); /* ---> Note 3 <--- */
Now you own two references to it.
> PyTuple_SetItem(pyFiveMinArgs, 4, pyRHost);
Now you own one reference; PyTuple_SetItem stole one.
> PyTuple_SetItem(pyOneHourArgs, 4, pyRHost);
Now you own no references. You must not call Py_DECREF on pyRHost after
this point (unless you obtain a new reference to it first).
Apart from all that, you're cheating in ways that can hurt you: tuples are
supposed to be immutable objects, and it's not strictly legal to mutate them
inside the loop. You'd be much better off not trying to micro-optimize
(i.e., build a new tuple each time you need one -- never use PyTuple_SetItem
on the same index twice for a given tuple; the code as-is is too clever to
ever work <0.9 wink>).
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