Menu
I want to extend a large C project with some new functionality, but I really want to write it in Python. Basically, I want to call Python code from C code. However, Python->C wrappers like SWIG allow for the OPPOSITE, that is writing C modules and calling C from Python.
I'm considering an approach involving IPC or RPC (I don't mind having multiple processes); that is, having my pure-Python component run in a separate process (on the same machine) and having my C project communicate with it by writing/reading from a socket (or unix pipe). my python component can read/write to socket to communicate. Is that a reasonable approach? Is there something better? Like some special RPC mechanism?
Thanks for the answer so far - however, i'd like to focus on IPC-based approaches since I want to have my Python program in a separate process as my C program. I don't want to embed a Python interpreter. Thanks!
1000
We can call a C function from Python program using the ctypes module.
The rawest, simplest way is to use the Python C API and write a wrapper for your C library which can be called from Python. This ties your module to CPython. The second way is to use ctypes which is an FFI for Python that allows you to load and call functions in C libraries directly.
std::string filename = "/home/abc/xyz/script.py"; std::string command = "python "; command += filename; system(command. c_str()); This does call and execute the python script. The print commands in the Python are being executed.
I recommend the approaches detailed here. It starts by explaining how to execute strings of Python code, then from there details how to set up a Python environment to interact with your C program, call Python functions from your C code, manipulate Python objects from your C code, etc.
EDIT: If you really want to go the route of IPC, then you'll want to use the struct module or better yet, protlib. Most communication between a Python and C process revolves around passing structs back and forth, either over a socket or through shared memory.
I recommend creating a Command struct with fields and codes to represent commands and their arguments. I can't give much more specific advice without knowing more about what you want to accomplish, but in general I recommend the protlib library, since it's what I use to communicate between C and Python programs (disclaimer: I am the author of protlib).
65
Have you considered just wrapping your python application in a shell script and invoking it from within your C application?
Not the most elegant solution, but it is very simple.
36
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
