Re: [pygame] Accessing C++ libs with ctypes

[jcupitt@xxxxxxxxx]

On 10 November 2015 at 00:52, Bartosz Debski <bartosz@xxxxxxxxxxxx> wrote:
> I know this is not directly pygame related question but I'm looking for help
> from more c++/Python able.
>
> I'm trying to get some use of Steam libraries which are C++. I have managed
> quite easily to load Steam library and initialize it with use of Python
> ctypes (Steam lib returns loaded Steam App)
>
> Now as I'm trying to get more useful information from documentation, all is
> in C++ and all references are C++.
>
> eg:
> "
> At the beginning of a game session, call
> SteamUserStats()->RequestCurrentStats() to fetch the user's data from the
> Steam back end. You will receive a UserStatsReceived_t callback when the
> data is ready.

In that C++, SteamUserStats() is returning a struct, and that struct
contains a function pointer called RequestCurrentStats() which you
must then call. The function pointer might be a plain struct member,
or it might be a class member, perhaps on the vfunc table. you'd need
to do some digging to find out exactly how it all works. It would be
rather difficult in ctypes.

Have you looked at cffi? It's a modern replacement for ctypes which
automates a lot of this stuff. You just give it a copy of the C++
headers and it generates all of the glue code for you. There's a nice
post here:

http://eli.thegreenplace.net/2013/03/09/python-ffi-with-ctypes-and-cffi

And some demos and examples in the cffi project:

https://bitbucket.org/cffi/cffi/src/default/demo/

John