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 path-
       name; 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 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 the unique watch descriptor associated with pathname  for  this  inotify
       instance.   If  pathname  was  not  previously being watched by this inotify instance, then the watch descriptor is newly
       allocated.  If pathname was already being watched, 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  file  system 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  appro-
       priately.

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.

       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 3.25 of the Linux man-pages project.  A description of the project,  and  information  about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2006-02-07                                       INOTIFY_ADD_WATCH(2)