c c++ epoll linux sockets

Epoll on regular files

Can epoll (on Linux) be somehow useful for regular files? I know it’s primarily used with sockets but just wonder.

Not really. epoll only makes sense for file descriptors which would normally exhibit blocking behavior on read/write, like pipes and sockets. Normal file descriptors will always either return a result or end-of-file more or less immediately, so epoll wouldn’t do anything useful for them.