phpMan > man > Log::Log4perl::MDC

NAME
    Log::Log4perl::MDC - Mapped Diagnostic Context

DESCRIPTION
    Log::Log4perl allows loggers to maintain global thread-specific data, called the Nested
    Diagnostic Context (NDC) and Mapped Diagnostic Context (MDC).

    The MDC is a simple thread-specific hash table, in which the application can stuff values under
    certain keys and retrieve them later via the "%X{key}" placeholder in
    "Log::Log4perl::Layout::PatternLayout"s.

    Log::Log4perl::MDC->put($key, $value);
        Store a value $value under key $key in the map.

    my $value = Log::Log4perl::MDC->get($key);
        Retrieve the content of the map under the specified key. Typically done by %X{key} in
        "Log::Log4perl::Layout::PatternLayout". If no value exists to the given key, "undef" is
        returned.

    my $text = Log::Log4perl::MDC->remove();
        Delete all entries from the map.

    Log::Log4perl::MDC->get_context();
        Returns a reference to the hash table.

    Please note that all of the methods above are class methods, there's no instances of this class.
    Since the thread model in perl 5.8.0 is "no shared data unless explicitly requested" the data
    structures used are just global (and therefore thread-specific).

LICENSE
    Copyright 2002-2013 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.

AUTHOR
    Please contribute patches to the project on Github:

        http://github.com/mschilli/log4perl

    Send bug reports or requests for enhancements to the authors via our

    MAILING LIST (questions, bug reports, suggestions/patches): log4perl-devel AT lists.net

    Authors (please contact them via the list above, not directly): Mike Schilli
    <m AT perlmeister.com>, Kevin Goess <cpan AT goess.org>

    Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy Bopp,
    Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, Anthony Foiani, James FitzGibbon,
    Carl Franks, Dennis Gregorovic, Andy Grundman, Paul Harrington, Alexander Hartmaier David Hull,
    Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett Rann, Peter Rabbitson, Erik
    Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac Yang.