NAME

io_uring_prep_futex_waitv - prepare a futex waitv request

SYNOPSIS

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

void io_uring_prep_futex_waitv(struct io_uring_sqe *sqe,
                               struct futex_waitv *futexv,
                               uint32_t nr_futex,
                               unsigned int flags);

DESCRIPTION

The io_uring_prep_futex_waitv(3) function prepares a futex wait request for multiple futexes at the same time. The submission queue entry sqe is setup for waiting on all futexes given by futexv and nr_futex is the number of futexes in that array. flags must be set to the io_uring specific futex flags.

Unlike io_uring_prep_futex_wait(3), the desired bitset mask and values are passed in futexv.

flags are currently unused and hence 0 must be passed.

This function prepares an async futex(2) waitv request. See that man page for details.

Available since kernel 6.7.

RETURN VALUE

None

ERRORS

The CQE res field will contain the result of the operation. See the related man page for details on possible values. 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.

NOTES

Unlike the sync futex syscalls that wait on a futex, io_uring does not support passing in a timeout for the request. Instead, applications are encouraged to use a linked timeout to abort the futex request at a given time, if desired.