Ralf Schoenian <r...@schoenian-online.de> wrote: > Ryan wrote: > > I've been using Python for many years now. It's a wonderful language > > that I enjoy using everyday. I'm now interested in getting to know > > more about the guts (C/C++) and extending it. But, extending python > > still seems like a black art to me. Is there anymore docs or info on > > extending it besides the standard sparse ones (http://www.python.org/ > > doc/2.5.2/ext/intro.html) that may give me more insight? Is there a > > class available? How can I learn more about the guts of python? How > > would one go about following an interest in contributing to the > > development of python. > > It is not exactly what you are looking for but nevertheless I am > thinking the article "Automatic C Library Wrapping -- Ctypes from the > Trenches" may be interesting for you. You can find it in the latest > Python Papers issue or simply following the link: > http://ojs.pythonpapers.org/index.php/tpp/article/view/71
Interesting - I didn't know about h2xml and xml2py before and I've done lots of ctypes wrapping! Something to help with the initial drudge work of converting the structures would be very helpful. ( http://pypi.python.org/pypi/ctypeslib/ ) I gave it a quick go and it worked fine. I had to edit the XML in one place to make it acceptable (removing a u from a hex number). The output of xml2py was an excellent place to start for the conversion, though I don't think I'd want to use an automated process like in the paper above as its output needed tweaking. ... Here are my thoughts on the conversion :- It converted an interface which looked like this (the inotify interface) struct inotify_event { int wd; /* Watch descriptor */ uint32_t mask; /* Mask of events */ uint32_t cookie; /* Unique cookie associating related events (for rename(2)) */ uint32_t len; /* Size of name field */ char name[]; /* Optional null-terminated name */ }; Into this class inotify_event(Structure): pass inotify_event._fields_ = [ ('wd', c_int), ('mask', uint32_t), ('cookie', uint32_t), ('len', uint32_t), ('name', c_char * 0), ] Which is a very good start. However it defined these which clearly aren't portable int32_t = c_int uint32_t = c_uint Whereas it should have been using the ctypes inbuilt types c_int32 c_uint32 Also I don't think c_char * 0 does anything sensible in ctypes, c_byte * 0 is what is required plus a bit of casting. This is a non-standard GNU extension to C though. All that said though, it looks like a great time saver. -- Nick Craig-Wood <n...@craig-wood.com> -- http://www.craig-wood.com/nick -- http://mail.python.org/mailman/listinfo/python-list
