Your example on read(2) is a good one. There's no way to fix it purely by changing the API because, by nature, the user chooses the size of the buffer. The dif

Your example on read(2) is a good one. There's no way to fix it purely by changing the API because, by nature, the user chooses the size of the buffer. The difference is that fd_set is a structure that's not defined by the user. If fd_set had a standard size, the kernel could verify that nfds is within the allowed range for the fd_set structure. The select(2) system call would be harder to misuse then, although misuse would still be possible by passing custom buffers instead of pointers to fd_set structures. In that sense, I think we agree on the "problem". It's indeed just a bit of Unix history, but I was surprised by it nonetheless.