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Config::Watch(3pm) User Contributed Perl Documentation Config::Watch(3pm)
NAME
Log::Log4perl::Config::Watch - Detect file changes
SYNOPSIS
use Log::Log4perl::Config::Watch;
my $watcher = Log::Log4perl::Config::Watch->new(
file => "/data/my.conf",
check_interval => 30,
);
while(1) {
if($watcher->change_detected()) {
print "Change detected!\n";
}
sleep(1);
}
DESCRIPTION
This module helps detecting changes in files. Although it comes with the "Log::Log4perl"
distribution, it can be used independly.
The constructor defines the file to be watched and the check interval in seconds.
Subsequent calls to "change_detected()" will
o return a false value immediately without doing physical file checks if
"check_interval" hasn't elapsed.
o perform a physical test on the specified file if the number of seconds specified in
"check_interval" have elapsed since the last physical check. If the file's
modification date has changed since the last physical check, it will return a true
value, otherwise a false value is returned.
Bottom line: "check_interval" allows you to call the function "change_detected()" as often
as you like, without paying the performing a significant performance penalty because file
system operations are being performed (however, you pay the price of not knowing about
file changes until "check_interval" seconds have elapsed).
The module clearly distinguishes system time from file system time. If your (e.g. NFS
mounted) file system is off by a constant amount of time compared to the executing
computer's clock, it'll just work fine.
To disable the resource-saving delay feature, just set "check_interval" to 0 and
"change_detected()" will run a physical file test on every call.
If you already have the current time available, you can pass it on to "change_detected()"
as an optional parameter, like in
change_detected($time)
which then won't trigger a call to "time()", but use the value provided.
SIGNAL MODE
Instead of polling time and file changes, "new()" can be instructed to set up a signal
handler. If you call the constructor like
my $watcher = Log::Log4perl::Config::Watch->new(
file => "/data/my.conf",
signal => 'HUP'
);
then a signal handler will be installed, setting the object's variable
"$self->{signal_caught}" to a true value when the signal arrives. Comes with all the
problems that signal handlers go along with.
SEE ALSO
AUTHOR
Mike Schilli, <log4perl AT perlmeister.com>
COPYRIGHT AND LICENSE
Copyright 2003 by Mike Schilli <m AT perlmeister.com> and Kevin Goess <cpan AT goess.org>.
This library is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
perl v5.10.0 2007-07-15 Config::Watch(3pm)
Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2012-05-24 16:03 @38.107.179.238 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)