x/sys/unix: Select returns (int, error) on linux, but just error elsewhere

[mdempsky]

Is this inconsistency intentional? Select is a POSIX function and has the same 'int' return value on all supported platforms where it's available, so it seems odd to only expose it on Linux.

(Motivation: I was trying to use github.com/jaracil/poll on OpenBSD, but ironically its Select-based fallback for non-Linux OSes is written assuming the Linux Select API.)

[ianlancetaylor]

This does seem like a bug. We can't change the existing function in the syscall package. I don't know how we feel about changing it in x/sys/unix.

Maybe we need to add a new function to x/sys/unix. Perhaps SelectN. Then we can provide a consistent interface across all Unix OS's. But since syscall is frozen, I don't think we want to change it for this.