man2/inotify_add_watch.2

   1 .\" man2/inotify_add_watch.2 - inotify_add_watch man page
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   3 .\" Copyright (C) 2005 Robert Love
   4 .\" and Copyright, 2006 Michael Kerrisk
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  26 .\" 2005-07-19 Robert Love <rlove@rlove.org> - initial version
  27 .\" 2006-02-07 mtk, various changes
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  29 .TH INOTIFY_ADD_WATCH 2 2006-02-07 "Linux" "Linux Programmer's Manual"
  30 .SH NAME
  31 inotify_add_watch \- add a watch to an initialized inotify instance
  32 .SH SYNOPSIS
  33 .B #include <inotify.h>
  34 .sp
  35 .BI "int inotify_add_watch(int " fd ", const char *" path ", uint32_t " mask );
  36 .SH DESCRIPTION
  37 .BR inotify_add_watch ()
  38 adds a watch on the file at pathname
  39 .I path
  40 to the inotify instance mapped by the file descriptor
  41 .I fd
  42 with the event mask given by the bitmask
  43 .IR mask .
  44 See
  45 .BR inotify (7)
  46 for a description of the bits that can be set in
  47 .IR mask .
  48
  49 A successful call to
  50 .BR inotify_add_watch ()
  51 returns the unique watch descriptor associated with
  52 .I path
  53 for this inotify instance.
  54 If
  55 .I path
  56 was not previously being watched by this inotify instance,
  57 then the watch descriptor is newly allocated.
  58 If
  59 .I path
  60 was already being watched, then the descriptor
  61 for the existing watch is returned.
  62
  63 The watch descriptor is returned by later
  64 .BR read (2)s
  65 from the inotify file descriptor.
  66 These reads fetch
  67 .I inotify_event
  68 structures indicating file system events;
  69 the returned watch descriptor identifies
  70 the object for which the event occurred.
  71 .SH "RETURN VALUE"
  72 On success,
  73 .BR inotify_add_watch ()
  74 returns a non-negative watch descriptor.
  75 On error \-1 is returned and
  76 .I errno
  77 is set appropriately.
  78 .SH ERRORS
  79 .TP
  80 .B EACCESS
  81 Read access to the given file is not permitted.
  82 .TP
  83 .B EBADF
  84 The given file descriptor is not valid.
  85 .TP
  86 .B EFAULT
  87 .I path
  88 points outside of the process's accessible address space.
  89 .TP
  90 .B EINVAL
  91 The given event mask contains no legal events.
  92 .TP
  93 .B ENOMEM
  94 Insufficient kernel memory was available.
  95 .TP
  96 .B ENOSPC
  97 The user limit on the total number of inotify watches was reached or the
  98 kernel failed to allocate a needed resource.
  99 .SH "HISTORY"
 100 Inotify was merged into the 2.6.13 Linux kernel.
 101 .SH "CONFORMING TO"
 102 This system call is Linux specific.
 103 .SH "BUGS"
 104 In kernels before 2.6.16, the
 105 .B IN_ONESHOT
 106 .I mask
 107 flag does not work.
 108 .SH "SEE ALSO"
 109 .BR inotify_init (2),
 110 .BR inotify_rm_watch (2),
 111 .BR inotify (7).