pnotify

   pnotify is an event notification framework for monitoring files and
   directories. It is designed to be portable across different Unix-like
   operating systems, and currently supports Linux and BSD. The [1]pnotify
   API is very similar to the [2]inotify API under Linux.
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              [3]Download | [4]Documentation | [5]Mailing list
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Rationale

   Kernel-based filesystem event notification is a relatively new
   phenonemon, and several different approaches have been taken by various
   operating systems. Linux uses inotify, BSD uses kqueue, Apple has
   kqueue and it's own Spotlight system calls, Solaris has FEM, Windows
   has the NTFS Change Journal and the ReadDirectoryChangesW function, and
   so forth.

   The goal of pnotify is to provide a simple, cross-platform API for
   monitoring filesystem events. The library will conceal all of the messy
   implementation-specific details from the user and help them to write
   more portable programs.

History

   pnotify was born out of an effort to port the inotify API from Linux to
   BSD. This initial effort took the form of a userspace library that
   would translate inotify requests into their kqueue(4) equivalent. After
   some time, it became clear that kqueue was not sophisticated enough to
   support all of the functionality of inotify. There was also the problem
   of threadsafety; inotify relies on shared global data structures, which
   is normal within the kernel but complicates the design of a userspace
   library.

   Eventually, it became clear that a new API was needed to address these
   portability and threadsafety issues. This new API became 'pnotify', to
   indicate that it is a portable subset of the inotify API.

Supported Platforms

   pnotify has been ported to the following platforms:
     * Linux 2.6
     * OpenBSD 4.0
     * NetBSD 3.1
     * FreeBSD 6.2
     * MacOS/X 10.4

   There are platforms that are not supported due to lack of developer
   resources. Interested parties with access to these platforms are
   encouraged to port the library to their platform. For example:

     * Sun OpenSolaris will soon get a similar API called FEM that could
       be supported.
     * Microsoft Windows has a filesystem event notification mechanism

   At the current time, there is no generic polling mechanism to use as a
   fallback for systems that don't have a kernel event mechanism like
   inotify or kqueue.

Usage

   When you run './configure && make && make install', pnotify is built as
   a shared library and installed under the /usr/local prefix.

   Even though pnotify is built as a shared library by default, it is
   easier for application developers to include pnotify.c and pnotify.h in
   their source tree and not depend on the existence of a shared library.

Download

   The source code may be downloaded from the [6]download page. You may
   also check out a working copy of the latest development sources by
   issuing the following command:

   svn checkout http://pnotify.googlecode.com/svn/trunk/ pnotify

   If you just want a quick peek at the source code, you can browse the
   [7]webSVN repository

Documentation

     * The pnotify(3) manpage in the following formats:
          + [8]HTML
          + [9]PostScript
          + [10]PDF
     * Future development will include support for non-blocking I/O
       syscalls. To see what this will look like, check out [11]nio.h
     * Doxygen-generated [12]annotated data structures and function
       reference.

Mailing List

   There is a mailing list for discussion about the pnotify library. Click
   [13]here to sign up, post a question or comment, or browse through the
   archives.

Contact the Author

   For more information, contact Mark Heily at [14]devel@heily.com

Related Links

     * [15]FAM - the original, unmaintained monitoring utility from SGI.
     * [16]gamin - the modern FAM replacement. Part of the GNOME project.
     * [17]libevent - a library for building event-driven servers.
       Supports socket events, but not filesystem events.
     __________________________________________________________________

   (C) 2007 Mark Heily.

References

   1. file://localhost/usr/home/mheily/proj/pnotify/manpage.html
   2. http://linux.die.net/man/7/inotify
   3. file://localhost/usr/home/mheily/proj/pnotify/index.html#download
   4. file://localhost/usr/home/mheily/proj/pnotify/index.html#docs
   5. file://localhost/usr/home/mheily/proj/pnotify/index.html#mlist
   6. http://code.google.com/p/pnotify/downloads/list
   7. http://pnotify.googlecode.com/svn/trunk/
   8. file://localhost/usr/home/mheily/proj/pnotify/manpage.html
   9. file://localhost/usr/home/mheily/proj/pnotify/manpage.ps
  10. file://localhost/usr/home/mheily/proj/pnotify/manpage.pdf
  11. http://pnotify.googlecode.com/svn/trunk/nio.h
  12. file://localhost/usr/home/mheily/proj/pnotify/doxygen/html/files.html
  13. http://groups.google.com/group/pnotify/topics
  14. mailto:devel@heily.com
  15. http://oss.sgi.com/projects/fam/
  16. http://www.gnome.org/~veillard/gamin/
  17. http://monkey.org/~provos/libevent/