inotify_add_watch
Section: System Calls (2)
Updated: 202-0-08
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NAME
inotify_add_watch - add a watch to an initialized inotify instance
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <sys/inotify.h>
int inotify_add_watch(int fd, const char *path, uint32_t mask);
DESCRIPTION
inotify_add_watch()
adds a new watch, or modifies an existing watch,
for the file whose location is specified in
path;
the caller must have read permission for this file.
The
fd
argument is a file descriptor referring to the
inotify instance whose watch list is to be modified.
The events to be monitored for
path
are specified in the
mask
bi-mask argument.
See
inotify(7)
for a description of the bits that can be set in
mask.
A successful call to
inotify_add_watch()
returns a unique watch descriptor for this inotify instance,
for the filesystem object (inode) that corresponds to
path.
If the filesystem object
was not previously being watched by this inotify instance,
then the watch descriptor is newly allocated.
If the filesystem object was already being watched
(perhaps via a different link to the same object), then the descriptor
for the existing watch is returned.
The watch descriptor is returned by later
read(2)s
from the inotify file descriptor.
These reads fetch
inotify_event
structures (see
inotify(7))
indicating filesystem events;
the watch descriptor inside this structure identifies
the object for which the event occurred.
RETURN VALUE
On success,
inotify_add_watch()
returns a watch descriptor (a nonnegative integer).
On error, -1 is returned and
errno
is set to indicate the error.
ERRORS
- EACCES
-
Read access to the given file is not permitted.
- EBADF
-
The given file descriptor is not valid.
- EEXIST
-
mask
contains
IN_MASK_CREATE
and
path
refers to a file already being watched by the same
fd.
- EFAULT
-
path
points outside of the process's accessible address space.
- EINVAL
-
The given event mask contains no valid events;
or
mask
contains both
IN_MASK_ADD
and
IN_MASK_CREATE;
or
fd
is not an inotify file descriptor.
- ENAMETOOLONG
-
path
is too long.
- ENOENT
-
A directory component in
path
does not exist or is a dangling symbolic link.
- ENOMEM
-
Insufficient kernel memory was available.
- ENOSPC
-
The user limit on the total number of inotify watches was reached or the
kernel failed to allocate a needed resource.
- ENOTDIR
-
mask
contains
IN_ONLYDIR
and
path
is not a directory.
STANDARDS
Linux.
HISTORY
Linux 2.6.13.
EXAMPLES
See
inotify(7).
SEE ALSO
inotify_init(2),
inotify_rm_watch(2),
inotify(7)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- STANDARDS
-
- HISTORY
-
- EXAMPLES
-
- SEE ALSO
-
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