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//+private
//+build linux
package sync
import "core:c"
import "core:time"
import "core:intrinsics"
import "core:sys/unix"
FUTEX_WAIT :: 0
FUTEX_WAKE :: 1
FUTEX_PRIVATE_FLAG :: 128
FUTEX_WAIT_PRIVATE :: (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
FUTEX_WAKE_PRIVATE :: (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
ESUCCESS :: 0
EINTR :: -4
EAGAIN :: -11
EFAULT :: -14
EINVAL :: -22
ETIMEDOUT :: -110
get_errno :: proc "contextless" (r: int) -> int {
if -4096 < r && r < 0 {
return r
}
return 0
}
internal_futex :: proc "contextless" (f: ^Futex, op: c.int, val: u32, timeout: rawptr) -> int {
code := int(intrinsics.syscall(unix.SYS_futex, uintptr(f), uintptr(op), uintptr(val), uintptr(timeout), 0, 0))
return get_errno(code)
}
_futex_wait :: proc "contextless" (f: ^Futex, expected: u32) -> bool {
err := internal_futex(f, FUTEX_WAIT_PRIVATE | FUTEX_WAIT, expected, nil)
switch err {
case ESUCCESS, EINTR, EAGAIN, EINVAL:
// okay
case ETIMEDOUT:
return false
case EFAULT:
fallthrough
case:
_panic("futex_wait failure")
}
return true
}
_futex_wait_with_timeout :: proc "contextless" (f: ^Futex, expected: u32, duration: time.Duration) -> bool {
if duration <= 0 {
return false
}
timespec_t :: struct {
tv_sec: c.long,
tv_nsec: c.long,
}
err := internal_futex(f, FUTEX_WAIT_PRIVATE | FUTEX_WAIT, expected, ×pec_t{
tv_sec = (c.long)(duration/1e9),
tv_nsec = (c.long)(duration%1e9),
})
switch err {
case ESUCCESS, EINTR, EAGAIN, EINVAL:
// okay
case ETIMEDOUT:
return false
case EFAULT:
fallthrough
case:
_panic("futex_wait_with_timeout failure")
}
return true
}
_futex_signal :: proc "contextless" (f: ^Futex) {
err := internal_futex(f, FUTEX_WAKE_PRIVATE | FUTEX_WAKE, 1, nil)
switch err {
case ESUCCESS, EINVAL, EFAULT:
// okay
case:
_panic("futex_wake_single failure")
}
}
_futex_broadcast :: proc "contextless" (f: ^Futex) {
err := internal_futex(f, FUTEX_WAKE_PRIVATE | FUTEX_WAKE, u32(max(i32)), nil)
switch err {
case ESUCCESS, EINVAL, EFAULT:
// okay
case:
_panic("_futex_wake_all failure")
}
}
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