'\" t
.\"     Title: eventfd_ctx_read
.\"    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_CTX_READ" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Events based on file descripto"
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.SH "NAME"
eventfd_ctx_read \- Reads the eventfd counter or wait if it is zero\&.
.SH "SYNOPSIS"
.HP \w'ssize_t\ eventfd_ctx_read('u
.BI "ssize_t eventfd_ctx_read(struct\ eventfd_ctx\ *\ " "ctx" ", int\ " "no_wait" ", __u64\ *\ " "cnt" ");"
.SH "ARGUMENTS"
.PP
\fIctx\fR
.RS 4
[in] Pointer to eventfd context\&.
.RE
.PP
\fIno_wait\fR
.RS 4
[in] Different from zero if the operation should not block\&.
.RE
.PP
\fIcnt\fR
.RS 4
[out] Pointer to the 64\-bit counter value\&.
.RE
.SH "DESCRIPTION"
.PP
Returns
\fB0\fR
if successful, or the following error codes:
.PP
\-EAGAIN : The operation would have blocked but
\fIno_wait\fR
was non\-zero\&. \-ERESTARTSYS : A signal interrupted the wait operation\&.
.PP
If
\fIno_wait\fR
is zero, the function might sleep until the eventfd internal counter becomes greater than zero\&.
.SH "COPYRIGHT"
.br