On 2010-07-02 18:27:39-0500, Charles Solar wrote:
> Threads and python do not mix very well. You need to handle locking and
> unlocking the gil at the boundaries of python and c++.
> There are several posts here about this problem, just search for thread or
> 'no current thread' in the archives.
> A month ago I posted a modified boost python that will handle the gil
> correctly for you if you want to give that a shot, or there is also TnFox
> which also handles threads correctly.
>
> Basically the short answer to your question is that you most certainly can,
> but you need to understand how the gil works and when and where you need to
> have it in order to do it correctly.
So, I need PyGILState_Ensure/PyGILState_Release around the
overridden method call, and PyEval_InitThreads in the module
initialization. Am I right? Is the following code OK?
#include <boost/python.hpp>
#include <boost/python/suite/indexing/vector_indexing_suite.hpp>
#include "../xyzzy.hpp"
using namespace boost::python;
using namespace xyzzy;
namespace {
class GIL_State_Guard
{
public:
GIL_State_Guard() :
state_(PyGILState_Ensure())
{
}
~GIL_State_Guard()
{
PyGILState_Release(state_);
}
private:
PyGILState_STATE state_;
};
class Data_Listener_Wrapper : public Data_Listener, public
wrapper<Data_Listener>
{
public:
void
on_data(const Data_Buffer& data)
{
if (override on_data = get_override("on_data")) {
GIL_State_Guard guard;
on_data(data);
}
default_on_data(data);
}
void
default_on_data(const Data_Buffer& data)
{
Data_Listener::on_data(data);
}
};
}// namespace
BOOST_PYTHON_MODULE(xyzzy) {
PyEval_InitThreads();
class_<Data_Buffer>("Data_Buffer")
.def(vector_indexing_suite<Data_Buffer>());
class_<Data_Listener_Wrapper, boost::noncopyable>("Data_Listener")
.def("on_data", &Data_Listener::on_data,
&Data_Listener_Wrapper::default_on_data);
class_<Data_Provider, boost::noncopyable>("Data_Provider")
.def("start", &Data_Provider::start)
.def("stop", &Data_Provider::stop);
}
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