The problem with “be careful” is that libraries often want to use the very unsafe API and there is no standard mechanism to expose safety. It’s fundamentally a

The problem with “be careful” is that libraries often want to use the very unsafe API and there is no standard mechanism to expose safety. It’s fundamentally a bad API design. It could be good. But it is not. There’s a reason this problem comes up on HN once or two a year. And don’t even get me started about printf grabbing a mutex for a stupid locale…