Winter Madness - Passing Python objects as Strings

Terry Reedy tjreedy at
Thu Jun 4 13:48:17 EDT 2009

Hendrik van Rooyen wrote:

> I can see that my explanation passes you by completely.
> I said, in my original post, that a can could not leave a process.
> A can is exactly the same as a C pointer, only its value has been
> converted to a string, so that you can pass it "in band" as
> part of a string. That is all it does. No more, no less.

If I understand correctly, your problem and solution was this:

You have multiple threads within a long running process.  One thread 
repeatedly reads a socket.  You wanted to be able to occasionally send 
an object to that thread.  Rather than rewrite the thread to also poll a 
queue.Queue(), which for CPython sends objects by sending a pointer, you 
converted pointers to strings and sent (multiplex) them via the text 
stream the thread was already reading -- and modified the thread to 
decode and act on the new type of message.

And you are willing to share the can code with someone who has a similar 
rare need and understands the danger of interpreting ints as addresses.



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