INOTIFY_INIT(2) Linux Programmer's Manual INOTIFY_INIT(2)

inotify_init, inotify_init1 - initialize an inotify instance

#include <sys/inotify.h>
int inotify_init(void);
int inotify_init1(int flags);

For an overview of the inotify API, see inotify(7).
inotify_init() initializes a new inotify instance and returns a file descriptor associated with a new inotify event queue.
If flags is 0, then inotify_init1() is the same as inotify_init(). The following values can be bitwise ORed in flags to obtain different behavior:
IN_NONBLOCK
Set the O_NONBLOCK file status flag on the open file description (see open(2)) referred to by the new file descriptor. Using this flag saves extra calls to fcntl(2) to achieve the same result.
IN_CLOEXEC
Set the close-on-exec (FD_CLOEXEC) flag on the new file descriptor. See the description of the O_CLOEXEC flag in open(2) for reasons why this may be useful.

On success, these system calls return a new file descriptor. On error, -1 is returned, and errno is set to indicate the error.

EINVAL
(inotify_init1()) An invalid value was specified in flags.
EMFILE
The user limit on the total number of inotify instances has been reached.
EMFILE
The per-process limit on the number of open file descriptors has been reached.
ENFILE
The system-wide limit on the total number of open files has been reached.
ENOMEM
Insufficient kernel memory is available.

inotify_init() first appeared in Linux 2.6.13; library support was added to glibc in version 2.4. inotify_init1() was added in Linux 2.6.27; library support was added to glibc in version 2.9.

These system calls are Linux-specific.

inotify_add_watch(2), inotify_rm_watch(2), inotify(7)
2019-03-06 Linux