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   futex    ( 2 )

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Ошибки (Error)

EACCES No read access to the memory of a futex word.

EAGAIN (FUTEX_WAIT, FUTEX_WAIT_BITSET, FUTEX_WAIT_REQUEUE_PI) The value pointed to by uaddr was not equal to the expected value val at the time of the call.

Note: on Linux, the symbolic names EAGAIN and EWOULDBLOCK (both of which appear in different parts of the kernel futex code) have the same value.

EAGAIN (FUTEX_CMP_REQUEUE, FUTEX_CMP_REQUEUE_PI) The value pointed to by uaddr is not equal to the expected value val3.

EAGAIN (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_CMP_REQUEUE_PI) The futex owner thread ID of uaddr (for FUTEX_CMP_REQUEUE_PI: uaddr2) is about to exit, but has not yet handled the internal state cleanup. Try again.

EDEADLK (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_CMP_REQUEUE_PI) The futex word at uaddr is already locked by the caller.

EDEADLK (FUTEX_CMP_REQUEUE_PI) While requeueing a waiter to the PI futex for the futex word at uaddr2, the kernel detected a deadlock.

EFAULT A required pointer argument (i.e., uaddr, uaddr2, or timeout) did not point to a valid user-space address.

EINTR A FUTEX_WAIT or FUTEX_WAIT_BITSET operation was interrupted by a signal (see signal(7)). In kernels before Linux 2.6.22, this error could also be returned for a spurious wakeup; since Linux 2.6.22, this no longer happens.

EINVAL The operation in futex_op is one of those that employs a timeout, but the supplied timeout argument was invalid (tv_sec was less than zero, or tv_nsec was not less than 1,000,000,000).

EINVAL The operation specified in futex_op employs one or both of the pointers uaddr and uaddr2, but one of these does not point to a valid object—that is, the address is not four- byte-aligned.

EINVAL (FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET) The bit mask supplied in val3 is zero.

EINVAL (FUTEX_CMP_REQUEUE_PI) uaddr equals uaddr2 (i.e., an attempt was made to requeue to the same futex).

EINVAL (FUTEX_FD) The signal number supplied in val is invalid.

EINVAL (FUTEX_WAKE, FUTEX_WAKE_OP, FUTEX_WAKE_BITSET, FUTEX_REQUEUE, FUTEX_CMP_REQUEUE) The kernel detected an inconsistency between the user-space state at uaddr and the kernel state—that is, it detected a waiter which waits in FUTEX_LOCK_PI or FUTEX_LOCK_PI2 on uaddr.

EINVAL (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_UNLOCK_PI) The kernel detected an inconsistency between the user-space state at uaddr and the kernel state. This indicates either state corruption or that the kernel found a waiter on uaddr which is waiting via FUTEX_WAIT or FUTEX_WAIT_BITSET.

EINVAL (FUTEX_CMP_REQUEUE_PI) The kernel detected an inconsistency between the user-space state at uaddr2 and the kernel state; that is, the kernel detected a waiter which waits via FUTEX_WAIT or FUTEX_WAIT_BITSET on uaddr2.

EINVAL (FUTEX_CMP_REQUEUE_PI) The kernel detected an inconsistency between the user-space state at uaddr and the kernel state; that is, the kernel detected a waiter which waits via FUTEX_WAIT or FUTEX_WAIT_BITSET on uaddr.

EINVAL (FUTEX_CMP_REQUEUE_PI) The kernel detected an inconsistency between the user-space state at uaddr and the kernel state; that is, the kernel detected a waiter which waits on uaddr via FUTEX_LOCK_PI or FUTEX_LOCK_PI2 (instead of FUTEX_WAIT_REQUEUE_PI).

EINVAL (FUTEX_CMP_REQUEUE_PI) An attempt was made to requeue a waiter to a futex other than that specified by the matching FUTEX_WAIT_REQUEUE_PI call for that waiter.

EINVAL (FUTEX_CMP_REQUEUE_PI) The val argument is not 1.

EINVAL Invalid argument.

ENFILE (FUTEX_FD) The system-wide limit on the total number of open files has been reached.

ENOMEM (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_CMP_REQUEUE_PI) The kernel could not allocate memory to hold state information.

ENOSYS Invalid operation specified in futex_op.

ENOSYS The FUTEX_CLOCK_REALTIME option was specified in futex_op, but the accompanying operation was neither FUTEX_WAIT, FUTEX_WAIT_BITSET, FUTEX_WAIT_REQUEUE_PI, nor FUTEX_LOCK_PI2.

ENOSYS (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_UNLOCK_PI, FUTEX_CMP_REQUEUE_PI, FUTEX_WAIT_REQUEUE_PI) A run-time check determined that the operation is not available. The PI-futex operations are not implemented on all architectures and are not supported on some CPU variants.

EPERM (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_CMP_REQUEUE_PI) The caller is not allowed to attach itself to the futex at uaddr (for FUTEX_CMP_REQUEUE_PI: the futex at uaddr2). (This may be caused by a state corruption in user space.)

EPERM (FUTEX_UNLOCK_PI) The caller does not own the lock represented by the futex word.

ESRCH (FUTEX_LOCK_PI, FUTEX_LOCK_PI2, FUTEX_TRYLOCK_PI, FUTEX_CMP_REQUEUE_PI) The thread ID in the futex word at uaddr does not exist.

ESRCH (FUTEX_CMP_REQUEUE_PI) The thread ID in the futex word at uaddr2 does not exist.

ETIMEDOUT The operation in futex_op employed the timeout specified in timeout, and the timeout expired before the operation completed.