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

NAME

       inotify_add_watch - add a watch to an initialized inotify instance

SYNOPSIS

       #include <sys/inotify.h>

       int inotify_add_watch(int fd, const char *pathname, uint32_t mask);

DESCRIPTION

       inotify_add_watch()  adds a new watch, or modifies an existing watch, for the file whose location is specified in pathname; 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 modi-
       fied.   The  events to be monitored for pathname are specified in the mask bit-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 pathname.  If the filesystem object was not previously being watched by this inotify instance, then the watch descrip-
       tor 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 ino-
       tify(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 nonnegative watch descriptor.	On error, -1 is returned and errno is set appropriately.

ERRORS

       EACCES Read access to the given file is not permitted.

       EBADF  The given file descriptor is not valid.

       EFAULT pathname points outside of the process's accessible address space.

       EINVAL The given event mask contains no valid events; or fd is not an inotify file descriptor.

       ENAMETOOLONG
	      pathname is too long.

       ENOENT A directory component in pathname 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.

VERSIONS

       Inotify was merged into the 2.6.13 Linux kernel.

CONFORMING TO

       This system call is Linux-specific.

SEE ALSO

       inotify_init(2), inotify_rm_watch(2), inotify(7)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15						      INOTIFY_ADD_WATCH(2)