Question

I have heard that Ctypes can cause crashes (or stop errors) in Python and windows. Should I stay away from their use? Where did I hear? It was back when I tried to control various aspects of windows, automation, that sort of thing.

I hear of swig, but I see Ctypes more often than not. Any danger here? If so, what should I watch out for?

I did search for ctype pro con python.

Answer 1

In terms of robustness, I still think swig is somewhat superior to ctypes, because it’s possible to have a C compiler check things more thoroughly for you; however, this is pretty moot by now (while it loomed larger in earlier ctypes versons), thanks to the argtypes feature @Mark already mentioned. However, there is no doubt that the runtime overhead IS much more significant for ctypes than for swig (and sip and boost python and other “wrapping” approaches): so, I think of ctypes as a convenient way to reach for a few functions within a DLL when the calls happen outside of a key bottleneck, not as a way to make large C libraries available to Python in performance-critical situations.

For a nice middle way between the runtime performance of swig (&c) and the convenience of ctypes, with the added bonus of being able to add more code that can use a subset of Python syntax yet run at just about C-code speeds, also consider Cython — a python-like language that compiles down to C and is specialized for writing Python-callable extensions and wrapping C libraries (including ones that may be available only as static libraries, not DLLs: ctypes wouldn’t let you play with those;-).