Simple but fast IPC method for a Python and C++ application?

Question

I have a GNU Radio application which utilizes both Python and C++ code. I want to be able to signal the C++ code of an event. If they were in the same scope I would normally use a simple boolean, but the code is separate to the point where some form of shared memory is required. The code in question is performance-critical so an efficient method is required.

I was initially thinking about a shared memory segment that is accessible by both Python and C++. Therefore I could set a flag in the python code and check it from C++. Since I just need a simple flag to pause the C++ code, would a semaphore suffice?

To be clear, I need to set a flag from Python and the C++ code will simply check this flag, and if it is set enter a busy loop.

So would trying to implement a shared memory segment between Python/C++ be a reasonable approach? How about a semaphore? On Linux, which is easier to implement?

Thanks!

Answer 1

Assuming this is two separate applications on one machine and you need decent real time performance you don't want to go with sockets. I would use a flag in shared memory, and probably use a semaphore to make sure both programs can't be accessing the flag at once. This library provides access to the semaphores and shared memory with Python and supports Python versions 2.4-3.1 (not 3.0): http://semanchuk.com/philip/posix_ipc

EDIT: Changed recommendation to using a semaphore protecting the flag in shared memory