Winter Madness - Passing Python objects as Strings

Hendrik van Rooyen mail at
Fri Jun 5 06:00:24 EDT 2009

"Terry Reedy" <tj. at> wrote:

> 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.

Yes and it puts what it finds on a queue. - it is a pre defined simple comma
delimited record.

>  You wanted to be able to occasionally send 
> an object to that thread. 

Close - to another thread that reads the queue, actually.

> Rather than rewrite the thread to also poll a 
> queue.Queue(), which for CPython sends objects by sending a pointer, 

It is in fact reading a queue, and what it gets out in the vast majority of
cases is the record that came from the socket.

> 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.

Basically yes - the newly created thread just puts a special text string
onto the queue. As I pointed out in my reply to Skip, this makes the
unpacking at the output of the queue standard, just using split(','),
and it is this simplicity that I wanted to preserve, as it happens almost
all of the time.

> 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.
> Correct?

Absolutely right on - I do not think that it is the kind of thing that should
be in the std lib, except as a kind of Hara Kiri bomb - 
uncan(a random number string), and die!

It would also help if someone who is more knowledgable about python
would have a look at the C code to make it more robust.

There are only 2 routines that matter  - it is about a screenfull.

- Hendrik

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