Function poll [src]

Prototype

pub fn poll(fds: []pollfd, timeout: i32) PollError!usize

Parameters

fds: []pollfdtimeout: i32

Possible Errors

NetworkSubsystemFailed

The network subsystem has failed.

SystemResources

The kernel had no space to allocate file descriptor tables.

Unexpected UnexpectedError

The Operating System returned an undocumented error code.

This error is in theory not possible, but it would be better to handle this error than to invoke undefined behavior.

When this error code is observed, it usually means the Zig Standard Library needs a small patch to add the error code to the error set for the respective function.

Source

  pub fn poll(fds: []pollfd, timeout: i32) PollError!usize {
    if (native_os == .windows) {
        switch (windows.poll(fds.ptr, @intCast(fds.len), timeout)) {
            windows.ws2_32.SOCKET_ERROR => switch (windows.ws2_32.WSAGetLastError()) {
                .WSANOTINITIALISED => unreachable,
                .WSAENETDOWN => return error.NetworkSubsystemFailed,
                .WSAENOBUFS => return error.SystemResources,
                // TODO: handle more errors
                else => |err| return windows.unexpectedWSAError(err),
            },
            else => |rc| return @intCast(rc),
        }
    }
    while (true) {
        const fds_count = cast(nfds_t, fds.len) orelse return error.SystemResources;
        const rc = system.poll(fds.ptr, fds_count, timeout);
        switch (errno(rc)) {
            .SUCCESS => return @intCast(rc),
            .FAULT => unreachable,
            .INTR => continue,
            .INVAL => unreachable,
            .NOMEM => return error.SystemResources,
            else => |err| return unexpectedErrno(err),
        }
    }
    unreachable;
}  