// std/net/epoll (the linux twin of std/net/kqueue): the raw bindings lower for
// a linux target with a byte-exact `epoll_event` layout — 12-byte stride on
// x86_64 (packed), modelled as an arch-branched `{events, data_lo, data_hi}`
// struct of u32 fields (no packed attribute, no unaligned access). Exercises
// create / ctl / wait + the readiness accessors so the IR covers the surface.
//
// Imports ONLY epoll.sx (libc-only — no std/build) so the .ir snapshot stays
// small and churns only when the bindings change. ir-only on the aarch64-macOS
// dev host (target x86_64-linux mismatches host arch+os → the runner asserts
// .exit + .ir + .stderr from `sx ir --target`); runtime behavior validates on a
// linux runner (see the module header's VALIDATION NOTE). The `inline if ARCH`
// in epoll.sx is resolved by the compiler's flatten pre-pass, so no build.sx.
ep :: #import "modules/std/net/epoll.sx";

main :: () -> i32 {
    epfd := ep.ep_create();
    // register read + peer-close interest on a fd, then drain readiness
    if !ep.ep_ctl(epfd, ep.EPOLL_CTL_ADD, 1, ep.EPOLLIN | ep.EPOLLRDHUP) { return 2; }
    ep.ep_ctl(epfd, ep.EPOLL_CTL_MOD, 1, ep.EPOLLIN | ep.EPOLLOUT);

    evs : [8]ep.EpollEvent = ---;
    sl : []ep.EpollEvent = .{ ptr = @evs[0], len = 8 };
    n := ep.ep_wait(epfd, sl, 8, 100);
    if n > 0 {
        if ep.ev_readable(evs[0]) { return ep.ev_fd(evs[0]); }
        if ep.ev_writable(evs[0]) { return 4; }
        if ep.ev_eof(evs[0]) { return 9; }
        if ep.ev_err(evs[0]) { return 8; }
    }
    ep.ep_ctl(epfd, ep.EPOLL_CTL_DEL, 1, 0);
    return xx size_of(ep.EpollEvent);   // 12 on x86_64
}