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Update use of libc::timespec to prepare for future libc version #55

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Merged
taiki-e merged 1 commit into from
Dec 3, 2022
Merged

Update use of libc::timespec to prepare for future libc version #55

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19 changes: 9 additions & 10 deletions src/epoll.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -116,15 +116,16 @@ impl Poller {
it_interval: TS_ZERO,
it_value: match timeout {
None => TS_ZERO,
Some(t) => libc::timespec {
tv_sec: t.as_secs() as libc::time_t,
tv_nsec: (t.subsec_nanos() as libc::c_long).into(),
},
Some(t) => {
let mut ts = TS_ZERO;
ts.tv_sec = t.as_secs() as libc::time_t;
ts.tv_nsec = (t.subsec_nanos() as libc::c_long).into();
ts
}
},
};

syscall!(syscall(
libc::SYS_timerfd_settime,
syscall!(timerfd_settime(
timer_fd as libc::c_int,
0 as libc::c_int,
&new_val as *const libc::itimerspec,
Expand Down Expand Up @@ -262,10 +263,8 @@ impl Drop for Poller {
}

/// `timespec` value that equals zero.
const TS_ZERO: libc::timespec = libc::timespec {
tv_sec: 0,
tv_nsec: 0,
};
const TS_ZERO: libc::timespec =
unsafe { std::mem::transmute([0u8; std::mem::size_of::<libc::timespec>()]) };
Comment on lines +266 to +267
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@taiki-e taiki-e Dec 3, 2022

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Hmm, I thought const transmute was stable at 1.56, but it seems to compile successfully at 1.47?

https://doc.rust-lang.org/stable/std/intrinsics/fn.transmute.html

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@notgull notgull Dec 3, 2022

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I saw that too, is that some kind of compiler magic?

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@wesleywiser wesleywiser Dec 3, 2022

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Yeah, I think it was special cased in the compiler for 1.46 and that special casing was removed in 1.56 when reading union fields in const contexts was stabilized.


/// Epoll flags for all possible readability events.
fn read_flags() -> libc::c_int {
Expand Down