libf | C as a Pure Functional Programming Language | Functional Programming library

Your ffmpeg version is too old. You need at least v4.0.

On macOS do not(!) develop against X11 / GLX. They are not natively supported! The X11 server for macOS supports only indirect GLX with limited functionality. You will get only sub par performance. And CUDA (used by libvis) is not supported.

On macOS all OpenGL development should use the native OpenGL framework: https://developer.apple.com/library/archive/documentation/GraphicsImaging/Conceptual/OpenGL-MacProgGuide/opengl_contexts/opengl_contexts.html

However take note that OpenGL has been declared deprecated by Apple.

In short: You'll at least have to modify your program to use the macOS OpenGL framework, or even bite the bullet and accept that macOS is not a well supported platform for your application.

It ended up being wifi issues. Switching to a wired connection fixed the issues I was having.

simple_read_from_buffer and simple_write_to_buffer are just convenience wrappers around copy_{to,from}_user for when all you need to do is service a read from userspace from a kernel buffer, or service a write from userspace to a kernel buffer.

From my understanding, the copy_..._user functions are more secure.

Neither version is "more secure" than the other. Whether or not one might be more secure than the other depends on the specific use case.

I would say that simple_{read,write}_... can in general be more secure since they do all the appropriate checks for you before copying. If all you need to do is service a read/write to/from a kernel buffer, then using simple_{read,write}_... is surely faster and less error-prone than manually checking and calling copy_{from,to}_user.

A good example where simple_read_from_buffer is useful would be:

Compile your shared object with

Listing [Python 3.Docs]: ctypes - A foreign function library for Python.

The cause it's a CTypes subtle behavior. c_char (and also c_wchar) arrays are silently converted to bytes (or str) when they are present as fields in a structure. This is being done via c_char_p (or c_wchar_p) which are NUL terminated, meaning that the "array" will be truncated if a NUL (0x00) char will be encountered, which is exactly your case. You can check that by looking at the field type.
Don't know why this is (maybe to ease the usage), but there are cases when it does more harm than good. It can be reproduced with Python code only.

code00.py