Module futex

Available on crate feature thread only.

Linux futex.

Futex is a very low-level mechanism for implementing concurrency primitives such as mutexes, rwlocks, and condvars. For a higher-level API that provides those abstractions, see rustix-futex-sync.

Examples

use rustix::thread::futex;
use std::sync::atomic::AtomicU32;

// Wake up one waiter.
futex::wake(futex, futex::Flags::PRIVATE, 1)?;

References

• Linux futex system call
• Linux futex feature

Structs

Flags

FUTEX_* flags for use with the functions in futex.

Timespec

struct timespec—A quantity of time in seconds plus nanoseconds.

Wait

For use with waitv.

WaitFlags

FUTEX2_* flags for use with the functions in Waitv.

WaitPtr

A pointer in the Wait struct.

WaitvFlags

Flags for use with the flags argument in waitv.

Enums

ClockId

CLOCK_* constants for use with clock_gettime.

WakeOp

FUTEX_OP_* operations for use with wake_op.

WakeOpCmp

FUTEX_OP_CMP_* operations for use with wake_op.

Constants

OWNER_DIED

FUTEX_OWNER_DIED

WAITERS

FUTEX_WAITERS

Functions

cmp_requeue

syscall(SYS_futex, uaddr, FUTEX_CMP_REQUEUE, val, val2, uaddr2, val3)

cmp_requeue_pi

syscall(SYS_futex, uaddr, FUTEX_CMP_REQUEUE_PI, 1, val2, uaddr2, val3)

fd

syscall(SYS_futex, uaddr, FUTEX_FD, val, NULL, NULL, 0)

lock_pi

syscall(SYS_futex, uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0)

lock_pi2

syscall(SYS_futex, uaddr, FUTEX_LOCK_PI2, 0, timeout, NULL, 0)

requeue

syscall(SYS_futex, uaddr, FUTEX_REQUEUE, val, val2, uaddr2, 0)

trylock_pi

syscall(SYS_futex, uaddr, FUTEX_TRYLOCK_PI, 0, NULL, NULL, 0)

unlock_pi

syscall(SYS_futex, uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0)

wait

syscall(SYS_futex, uaddr, FUTEX_WAIT, val, timeout, NULL, 0)

wait_bitset

syscall(SYS_futex, uaddr, FUTEX_WAIT_BITSET, val, timeout, NULL, val3)

wait_requeue_pi

syscall(SYS_futex, uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0)

waitv

futex_waitv(waiters.as_ptr(), waiters.len(), flags, timeout, clockd)— Wait on an array of futexes, wake on any.

wake

syscall(SYS_futex, uaddr, FUTEX_WAKE, val, NULL, NULL, 0)

wake_bitset

syscall(SYS_futex, uaddr, FUTEX_WAKE_BITSET, val, NULL, NULL, val3)

wake_op

syscall(SYS_futex, uaddr, FUTEX_WAKE_OP, val, val2, uaddr2, val3)

Type Aliases

Nsecs

A type for the tv_nsec field of Timespec.

Secs

A type for the tv_sec field of Timespec.