On 25/02/2023 23:45, Jon Ribbens via Python-list wrote:
I think it is the case that x += 1 is atomic but foo.x += 1 is not.
No that is not true, and has never been true. :>>> def x(a): :... a += 1 :... :>>> :>>> dis.dis(x) 1 0 RESUME 0 2 2 LOAD_FAST 0 (a) 4 LOAD_CONST 1 (1) 6 BINARY_OP 13 (+=) 10 STORE_FAST 0 (a) 12 LOAD_CONST 0 (None) 14 RETURN_VALUE :>>> As you can see there are 4 byte code ops executed. Python's eval loop can switch to another thread between any of them. Its is not true that the GIL provides atomic operations in python. Barry -- https://mail.python.org/mailman/listinfo/python-list
