Function filedescriptor::poll

pub fn poll(pfd: &mut [pollfd], duration: Option<Duration>) -> Result<usize>

Examines a set of FileDescriptors to see if some of them are ready for I/O, or if certain events have occurred on them.

This uses the system native readiness checking mechanism, which on Windows means that it does NOT use IOCP and that this only works with sockets on Windows. If you need IOCP then the mio crate is recommended for a much more scalable solution.

On macOS, the poll(2) implementation has problems when used with eg: pty descriptors, so this implementation of poll uses the select(2) interface under the covers. That places a limit on the maximum file descriptor value that can be passed to poll. If a file descriptor is out of range then an error will returned. This limitation could potentially be lifted in the future.

On Windows, WSAPoll is used to implement readiness checking, which has the consequence that it can only be used with sockets.

If duration is None, then poll will block until any of the requested events are ready. Otherwise, duration specifies how long to wait for readiness before giving up.

The return value is the number of entries that were satisfied; 0 means that none were ready after waiting for the specified duration.

The pfd array is mutated and the revents field is updated to indicate which of the events were received.