man-pages/man2/inotify_init.2

.\" man2/inotify_init.2 - inotify_init man page
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.\" Copyright (C) 2005 Robert Love
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.\" 2005-07-19 Robert Love <rlove@rlove.org> - initial version
.\" 2006-02-07 mtk, minor changes
.\" 2008-10-10 mtk: add description of inotify_init1()
.\"
.TH INOTIFY_INIT 2 2008-10-10 "Linux" "Linux Programmer's Manual"
.SH NAME
inotify_init, inotify_init1 \- initialize an inotify instance
.SH SYNOPSIS
.nf
.B #include <sys/inotify.h>
.sp
.B "int inotify_init(void);"
.BI "int inotify_init1(int " flags );
.fi
.SH DESCRIPTION
.BR inotify_init ()
initializes a new inotify instance and returns a file descriptor associated
with a new inotify event queue.

If
.I flags
is 0, then
.BR inotify_init1 ()
is the same as
.BR inotify_init ().
The following values can be bitwise ORed in
.IR flags
to obtain different behavior:
.TP 12
.B IN_NONBLOCK
Set the
.BR O_NONBLOCK
file status flag on the new open file description.
Using this flag saves extra calls to
.BR fcntl ()
to achieve the same result.
.TP
.B IN_CLOEXEC
Set the close-on-exec
.RB ( FD_CLOEXEC)
flag on the new file descriptor.
See the description of the 
.B O_CLOEXEC
flag in
.BR open (2)
for reasons why this may be useful.
.SH "RETURN VALUE"
On success, these system calls return a new file descriptor.
On error, \-1 is returned, and
.I errno
is set to indicate the error.
.SH ERRORS
.TP
.B EINVAL
.RB ( inotify_init1 ())
An invalid value was specified in
.IR flags .
.TP
.B EMFILE
The user limit on the total number of inotify instances has been reached.
.TP
.B ENFILE
The system limit on the total number of file descriptors has been reached.
.TP
.B ENOMEM
Insufficient kernel memory is available.
.SH VERSIONS
.BR inotify_init ()
first appeared in Linux 2.6.13.
.BR inotify_init1 ()
was added in Linux 2.6.27.
.SH "CONFORMING TO"
These system calls are Linux-specific.
.SH "SEE ALSO"
.BR inotify_add_watch (2),
.BR inotify_rm_watch (2),
.BR inotify (7)