[Python-Dev] Overwriting objects before deallocating them

Tim Peters tim.one@comcast.net
Fri, 24 May 2002 11:46:22 -0400

[Andrew Kuchling]
> In the cryptography toolkit, the deallocators in the C extensions all
> overwrite the object's contents before deallocating it.  Is this dodgy
> practice?  Is it likely or possible that some day PyObject_Del will
> need to look at the contents of a non-GC-supporting object before
> freeing it?

Nope.  I prefer to write PyObject_Free, because it's exactly the same as
PyObject_Del, and spelling it "free" doesn't conjure up misleading images of
this having something to do with destructors or refcounts, or even with
*objects*.  They don't -- all they do is release the raw memory.  I'm not
sure why, but there's a widespread intransigent belief that it's somehow
purer to say "del" for freeing memory that happened to hold an object.  The
memory API is full of now-institutionalized TMTOWTDI.

> (Encryption or hashing objects are not containers, and it's highly
> unlikely they ever will be, so they'll never need to support GC
> traversal.)

You would have to use PyObject_GC_Del if they did, and so that's a different
question entirely <wink>.