pollfd_t.revents is marked private

[pwaller]

This is a field you need to be able to read/write to use poll.

nc/src/platform/linux-types/uapi/asm_generic/poll.rs

Lines 31 to 37 in ac659c6

	#[repr(C)]
	#[derive(Debug, Default, Clone)]
	pub struct pollfd_t {
	pub fd: i32,
	pub events: i16,
	revents: i16,
	}

[pwaller]

Additionally the poll types have a type of i32, but the fields on pollfd_t which use those bits are an i16, so you have to cast the constants unnecessarily currently:

nc/src/platform/linux-types/uapi/asm_generic/poll.rs

Lines 9 to 24 in ac659c6

	/// These are specified by `iBCS2`
	pub const POLLIN: i32 = 0x0001;
	pub const POLLPRI: i32 = 0x0002;
	pub const POLLOUT: i32 = 0x0004;
	pub const POLLERR: i32 = 0x0008;
	pub const POLLHUP: i32 = 0x0010;
	pub const POLLNVAL: i32 = 0x0020;
	/// The rest seem to be more-or-less nonstandard. Check them!
	pub const POLLRDNORM: i32 = 0x0040;
	pub const POLLRDBAND: i32 = 0x0080;
	pub const POLLWRNORM: i32 = 0x0100;
	pub const POLLWRBAND: i32 = 0x0200;
	pub const POLLMSG: i32 = 0x0400;
	pub const POLLREMOVE: i32 = 0x1000;
	pub const POLLRDHUP: i32 = 0x2000;

[pwaller]

And the poll function returns a useful integer:

nc/src/platform/linux-x86_64/call.rs

Line 4619 in 6da9f75

pub unsafe fn poll(fds: &mut [pollfd_t], timeout: i32) -> Result<(), Errno> {

Manpage:

Upon successful completion, poll() shall return a non-negative value. A positive value indicates the total number of pollfd structures that have selected events (that is, those for which the revents member is non-zero). A value of 0 indicates that the call timed out and no file descriptors have been selected.