On Mon, May 28, 2012 at 6:37 AM, Suresh Joshi <sure...@gmail.com> wrote: > Hello all! > > I had a question about how to handle void* and HWNDs from within Python > using Boost::Python and Py++. Reading through the Py++ documentation, I'm > loving how I can slice and dice my classes/wrappers and seemingly do > whatever I want with them, but there's still A LOT I haven't figured out. > > I've found a previous set of similar questions here: > http://boost.2283326.n4.nabble.com/Wrapping-and-Passing-HWND-with-Boost-Python-td4598953.html > but didn't fully understand the automated implementation details. > > All the relevant code is posted at the end, but my main questions were as > follows. > > (1) Using the win32gui Python library, HWNDs are passed around as ints > describing the address of the window. These can be reinterpret_cast'ed into > HWNDs in C++ and that seems to work fine. However, using Py++, how can I > automatically inject a reinterpret_cast into Foo's constructor, or the > initializer list of a constructor wrapper? > > I've found these commands, > .add_declaration_code(...) > .add_registration_code(...) > .add_wrapper_code(...) > but they don't place code where I need it to go. > > So, is there a command that I should be using? My goal is to not touch my > Foo.hpp code (as in, no added code, no helper code), so I would like > everything to stay within the Boost::Python generated wrapper code > (FooWrapper.cpp).
What you can do is to generate global function, which takes HWND as integer, does casting and returns your object (via std::auto_ptr). Then, you can add registration code, that use boost::python::make_constructor function to create your class. > (2) From Python, I would like to manipulate the memory of a buffer stored > within Foo. In my REAL code, the only accessor I can use is Address() which > returns a void pointer, which Py++/BP flips into an opaque pointer (which I > don't think I can use to manipulate m_buffer's memory in Python). > > One option is ctypes, but I frankly just don't know how to combine that with > BP for the purpose of manipulating data behind a void*, even after having > looked at the ctypes integration code in the Py++ docs. > > The other option is to do something like what I did with the fake VoidPtr() > accessor. I could create accessors like VoidPtrAsUChar() for example, and > then expose those using the return_addressof call policy (hopefully!). If > this is, in fact, a valid approach, then I have the same question as > above... > > Given that I can't change the Foo.hpp code, is there a clean way of > injecting those AsUChar, AsInt, As... helper methods straight into the > wrapper code, so that they call Address() internally and then > reinterpret_cast the returned void* into something more useful and > accessible in Python? I think Py++ repository contains ctypes + boost.python integration code example. It worse to check it. Regards, Roman. _______________________________________________ Cplusplus-sig mailing list Cplusplus-sig@python.org http://mail.python.org/mailman/listinfo/cplusplus-sig
