Lots of C library code for decades carried man page warnings it was unstable for use in async, re-entrant and recursive contexts. We learned how to cope and incrementally re-entrant safe versions deployed without too much API instability. Maybe time has healed wounds and caused me memory loss of the pain of discovery you'd tripped over them.
String parsing which tokenised in-place. DNS calls which used static buffers. Things which exploited Vax specific stack behaviour.
String parsing which tokenised in-place. DNS calls which used static buffers. Things which exploited Vax specific stack behaviour.
I think the GIL has been a blessing and a curse.