Redefined Horizons wrote: > I still new to Python, and I've only dabbled in C, but I've got my > first project I need to tackle that involves both languages. I was > hoping to get some advice on how to proceed. > > There is a third-party application that I need to work with. It is > closed-source, but it exposes a C API. I want to wrap this C API so > that it is available from Python. I have no ability to modify the C > API of the third part application. > > Do I the C functions that I wrap in an extensions module for Python > need to be in a certian format? If so, I will have to write an > intermediate DLL in C that wraps the third-party application and > exports the functions in a form that Python can use. > > Or can an extension module for Python wrap any C function? If this is > the case I think I can skip the intermediate C DLL. > > Are there any advantages to using the intermediate DLL written in C in > this particular case where I will not have ability to manipulate the C > API of the third party application directly? (For example, if the > third-party application developers are willing to call a "call-back" > function that must be written in C, but not Python. Could the same > extension module export both C functions and serve as a Python > module?) > > Thanks, > > Scott Huey
John Machin has answered most of your questions in a separate post. All you need is to take a look at ctypes module for Python. You can call virtually any C based API that is stored in a .DLL using ctypes. I've called .DLL APIs for Castelle's Faxpress, Expervision's OCR toolkit and Softrak's ADS.DLL with no problems. The trick is creating some functions/classes that help with the C structures that need to be passed back and forth. For that you will probably also need to take a look at the Python struct module, but ctypes has some built-in helper functions also. ctypes can be located here: http://starship.python.net/crew/theller/ctypes/ -Larry Bates -- http://mail.python.org/mailman/listinfo/python-list
