Embedding Python, threading and scalability

[Jeff Epler]

On Thu, Jul 10, 2003 at 07:48:57PM -0400, Aahz wrote:
> In article <mailman.1057877718.17081.python-list at python.org>,
> Jeff Epler  <jepler at unpythonic.net> wrote:
> >On Thu, Jul 10, 2003 at 03:54:14PM -0400, Aahz wrote:
> >>
> >> Other people have mentioned Perl and Tcl in this thread.  I wonder how
> >> they deal with the problem of loading DLLs with static data.
> >
> >As far as I know, tcl enforces a one interpreter to one thread
> >requirement.  An extension should have only thread-local data, using a
> >Tcl-supplied API.
> 
> What happens when Tcl wants to interact with some 3rd-party DLL that is
> *not* thread-safe?

I guess you'd have to do your own locking.  Tcl has standard C APIs for
Conditions, Mutexes, and thread-specific data, see the Thread(3) manpage.
You'd have to surround all non-reentrant calls with Tcl_MutexLock(m)
... Tcl_MutexUnlock(m).  If two extensions wanted to use the same
non-thread-safe library, they'd have to cooperate in some way to use
the same 'm' to Tcl_Mutex*().  I don't know if there's a standard way to
do this, but I think that having the mutex defined in a shared lib they
both link might work.

Jeff