On 4/23/06, "Martin v. Löwis" <[EMAIL PROTECTED]> wrote:
Eh, hang on. The reason to use Py_CLEAR() isn't that the pointer may be used after the Py_DECREF(), but that it may be used *as a result of DECREF'ing*. DECREFs can cause cleanup, which can execute arbitrary Python or C code through finalizers or weakref callbacks. So whatever you're doing after the Py_DECREF/Py_CLEAR call is immaterial to the decision to use either. You should use Py_CLEAR when the pointer you are DECREF'ing *might* go away, and is accessible from outside the function ( i.e. it isn't only reachable through automatic variables.)
However, I agree that it should be a conscious decision, and not an automatism.
-- For pointer that live on the heap, Py_[X]DECREF is usually
done because either
a) the memory block containing the pointer is about to be
released (e.g. when a tuple is deallocated), or
b) the pointer is about to be changed to point to something
else (e.g. a setitem operation)
Eh, hang on. The reason to use Py_CLEAR() isn't that the pointer may be used after the Py_DECREF(), but that it may be used *as a result of DECREF'ing*. DECREFs can cause cleanup, which can execute arbitrary Python or C code through finalizers or weakref callbacks. So whatever you're doing after the Py_DECREF/Py_CLEAR call is immaterial to the decision to use either. You should use Py_CLEAR when the pointer you are DECREF'ing *might* go away, and is accessible from outside the function ( i.e. it isn't only reachable through automatic variables.)
However, I agree that it should be a conscious decision, and not an automatism.
Thomas Wouters < [EMAIL PROTECTED]>
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