'\" t
.\"     Title: futex_wait_setup
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: Futex API reference
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "FUTEX_WAIT_SETUP" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Futex API reference"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
futex_wait_setup \- Prepare to wait on a futex
.SH "SYNOPSIS"
.HP \w'int\ futex_wait_setup('u
.BI "int futex_wait_setup(u32\ __user\ *\ " "uaddr" ", u32\ " "val" ", unsigned\ int\ " "flags" ", struct\ futex_q\ *\ " "q" ", struct\ futex_hash_bucket\ **\ " "hb" ");"
.SH "ARGUMENTS"
.PP
\fIuaddr\fR
.RS 4
the futex userspace address
.RE
.PP
\fIval\fR
.RS 4
the expected value
.RE
.PP
\fIflags\fR
.RS 4
futex flags (FLAGS_SHARED, etc\&.)
.RE
.PP
\fIq\fR
.RS 4
the associated futex_q
.RE
.PP
\fIhb\fR
.RS 4
storage for hash_bucket pointer to be returned to caller
.RE
.SH "DESCRIPTION"
.PP
Setup the futex_q and locate the hash_bucket\&. Get the futex value and compare it with the expected value\&. Handle atomic faults internally\&. Return with the hb lock held and a q\&.key reference on success, and unlocked with no q\&.key reference on failure\&.
.SH "RETURN"
.PP
0 \- uaddr contains val and hb has been locked; <1 \- \-EFAULT or \-EWOULDBLOCK (uaddr does not contain val) and hb is unlocked
.SH "AUTHOR"
.PP
\fBRusty Russell\fR <\&rusty@rustcorp.com.au\&>
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br