NAME

       io_uring_prep_futex_wake - prepare a futex wake request

SYNOPSIS

       #include <linux/futex.h>
       #include <unistd.h>
       #include <liburing.h>

       void io_uring_prep_futex_wake(struct io_uring_sqe *sqe,
                                     uint32_t *futex,
                                     uint64_t val,
                                     uint64_t mask,
                                     uint32_t futex_flags,
                                     unsigned int flags);

DESCRIPTION

       The io_uring_prep_futex_wake(3) function prepares a futex wake request. The submission queue entry sqe is
       setup  for  waking  any  waiters  on  the  futex indicated by futex and at most val futexes.  futex_flags
       indicates the futex2(2) modifier flags, and io_uring futex flags of flags .

       If a given bitset for who to wake is desired, then that must be set in mask .  Use FUTEX_BITSET_MATCH_ANY
       to match any waiter on the given futex.

       flags are currently unused and hence 0 must be passed.

       This function prepares an async futex(2) wake request. See that man  page  for  details.  Note  that  the
       io_uring  futex  wake  request  is  similar to the FUTEX_WAKE_BITSET operation, as FUTEX_WAKE is a strict
       subset of that.

       Available since kernel 6.7.

RETURN VALUE

       None

ERRORS

       The CQE res field will contain the result of the operation. On success, the value will be the index  into
       futexv  which received a wakeup. See the related man page for details on possible values for errors. Note
       that where synchronous system calls will return -1 on failure and set errno to the  actual  error  value,
       io_uring never uses errno.  Instead it returns the negated errno directly in the CQE res field.

SEE ALSO

       io_uring_get_sqe(3),   io_uring_submit(3),   io_uring_prep_futex_wait(3),   io_uring_prep_futex_waitv(3),
       futex(2) futex2(2)

liburing-2.5                                      Sep 29, 2023                       io_uring_prep_futex_wake(3)