The most basic IPC between Python and C++

Question

I'm writing a DLL (Windows, MS VS 17) in C++ which requires to call a Python script at some point - it should read a json-encoded string, process it and give back the json-encoded result. There is no need for asynchronous mode or "speed of light", but I need more or less fast response - ie within 1-5 seconds max. Here are the approaches I considered and the comments:

1. Pass the string as a command line argument . This is, obviously, not the best choice - let alone string length limit.
2. Use a temporary file . It will be the best to avoid such practice in my case, because although I need to run the Python-part generally once per launch, the number of launches may be quite big.
3. Use a TCP/IP socket (for localhost ) / pipe . Both seem to be an overkill for such a task - I do not have a continuous flow of data which changes constantly. Besides, in Windows it might be a pain.
4. Use shared memory . Shared memory would be a nice option but I couldn't find a way to use the same segment both in C++ and Python.
5. Embed Python part into C++ . I have 2 concerns here: a) Python env should be installed on the target machine, shouldn't it? b) A python script has an import , which imports a package, installed from pip and, unfortunately, I cannot avoid it. Is there a proper way to work with imports when embedding?

Is there a simple way to interoperate between C++ and Python in my case?

Answer 1

Since you're targeting Windows, option (2) is the best, but use a temporary file CreateFile(...FILE_ATTRIBUTE_TEMPORARY) . That's effectively shared memory (at the OS level, both are managed by the Virtual Memory Manager) but you get file semantics.