'\" t
.\"     Title: eventfd_signal
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: Events based on file descriptors
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "EVENTFD_SIGNAL" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Events based on file descripto"
.\" -----------------------------------------------------------------
.\" * 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"
eventfd_signal \- Adds \fIn\fR to the eventfd counter\&.
.SH "SYNOPSIS"
.HP \w'__u64\ eventfd_signal('u
.BI "__u64 eventfd_signal(struct\ eventfd_ctx\ *\ " "ctx" ", __u64\ " "n" ");"
.SH "ARGUMENTS"
.PP
\fIctx\fR
.RS 4
[in] Pointer to the eventfd context\&.
.RE
.PP
\fIn\fR
.RS 4
[in] Value of the counter to be added to the eventfd internal counter\&. The value cannot be negative\&.
.RE
.SH "DESCRIPTION"
.PP
This function is supposed to be called by the kernel in paths that do not allow sleeping\&. In this function we allow the counter to reach the ULLONG_MAX value, and we signal this as overflow condition by returning a POLLERR to poll(2)\&.
.PP
Returns the amount by which the counter was incremented\&. This will be less than
\fIn\fR
if the counter has overflowed\&.
.SH "COPYRIGHT"
.br