Is python sys.stderr.write atomic? How to determine thread safety of builtin functions?

Question

I'm trying to understand atomicity of this command with

import dis
import sys
dis.dis(sys.stderr.write)

However, I get "TypeError: don't know how to disassemble builtin_function_or_method objects"

How to determine atomicity of python built-in functions?

Answer 1

You can't disassemble sys.stderr.write - it's not a python function, but a function written in C and only available in binary after installation.

Being a C function, it is implicitly thread-safe because of the Global Interpreter Lock (GIL).