| .\" Copyright (C) 2021 Stefan Roesch <shr@fb.com> |
| .\" |
| .\" SPDX-License-Identifier: LGPL-2.0-or-later |
| .\" |
| .TH io_uring_sqe_set_data 3 "November 15, 2021" "liburing-2.1" "liburing Manual" |
| .SH NAME |
| io_uring_sqe_set_data \- set user data for submission queue event |
| .SH SYNOPSIS |
| .nf |
| .B #include <liburing.h> |
| .PP |
| .BI "void io_uring_sqe_set_data(struct io_uring_sqe *" sqe "," |
| .BI " void *" user_data ");" |
| .BI " |
| .BI "void io_uring_sqe_set_data64(struct io_uring_sqe *" sqe "," |
| .BI " __u64 " data ");" |
| .fi |
| .SH DESCRIPTION |
| .PP |
| The |
| .BR io_uring_sqe_set_data (3) |
| function stores a |
| .I user_data |
| pointer with the submission queue entry |
| .IR sqe . |
| |
| The |
| .BR io_uring_sqe_set_data64 (3) |
| function stores a 64-bit |
| .I data |
| value with the submission queue entry |
| .IR sqe . |
| |
| After the caller has requested a submission queue entry (SQE) with |
| .BR io_uring_get_sqe (3) , |
| they can associate a data pointer or value with the SQE. Once the completion |
| arrives, the function |
| .BR io_uring_cqe_get_data (3) |
| or |
| .BR io_uring_cqe_get_data64 (3) |
| can be called to retrieve the data pointer or value associated with the |
| submitted request. |
| |
| Note that if neither of these functions are called, or the |
| .I user_data |
| field in the |
| .IR sqe |
| isn't set manually either, then the field may contain a value from a previous |
| use of this sqe. If an application relies on always having a valid |
| .I user_data |
| value present, it must always assign one to each sqe. |
| |
| .SH RETURN VALUE |
| None |
| .SH SEE ALSO |
| .BR io_uring_get_sqe (3), |
| .BR io_uring_cqe_get_data (3) |
