/*
 * Copyright (c) 2009-2012 Zmanda, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 * Contact information: Zmanda Inc., 465 S. Mathilda Ave., Suite 300
 * Sunnyvale, CA 94085, USA, or: http://www.zmanda.com
 */

%perlcode %{

=head1 NAME

Amanda::Debug - support for debugging Amanda applications

=head1 SYNOPSIS

  use Amanda::Util qw( :constants );

  Amanda::Util::setup_application("amcooltool", "server", $CONTEXT_CMDLINE);

  debug("this is a debug message");
  die("Unable to frobnicate the ergonator");

See C<debug.h> for a more in-depth description of the logging
functionality of this module.

=head1 DEBUG LOGGING

Several debug logging functions, each taking a single string, are
available:

=over

=item C<error> - also aborts the program to produce a core dump

=item C<critical> - exits the program with C<$error_exit_status>

=item C<warning>

=item C<message>

=item C<info>

=item C<debug>

=back

Perl's built-in C<die> and C<warn> functions are patched to call
C<critical> and C<warning>, respectively.

All of the debug logging functions are available via the export tag
C<:logging>.

Applications can adjust the handling of log messages with
C<add_amanda_log_handler($hdlr)> where C<$hdlr> is a predefined log
destination.  The following destinations are available in this
package.  See L<Amanda::Logfile> for C<$amanda_log_trace_log>.

  $amanda_log_null
  $amanda_log_stderr
  $amanda_log_syslog

=head1 ADVANCED USAGE

Most applications should use L<Amanda::Util>'s C<setup_application> to
initialize the debug libraries.  The initialization functions
available from this module are thus considered "advanced", and the
reader is advised to consult the C header, C<debug.h>, for details.

Briefly, the functions C<dbopen> and C<dbrename> are used to open a
debug file whose pathname includes all of the relevant
information. C<dbclose> and C<dbreopen> are used to close that debug
file before transferring control to another process.

C<$error_exit_status> is the exit status with which C<critical> will
exit.

All of the initialization functions and variables are available via
the export tag C<:init>.

The current debug file's integer file descriptor (I<not> a Perl
filehandle) is available from C<dbfd()>.  Likewise, C<dbfn()> returns
the filename of the current debug file.

C<debug_dup_stderr_to_debug()> redirects, at the file-descriptor
level, C<STDERR> into the debug file.  This is useful when running
external applications which may produce error output.

=cut


%}
