=head1 NAME

Coro::BDB - truly asynchronous bdb access

=head1 SYNOPSIS

   use Coro::BDB;
   use BDB;

   # can now use any of the bdb requests

=head1 DESCRIPTION

This module is an L<AnyEvent> user, you need to make sure that you use and
run a supported event loop.

This module implements a thin wrapper around the L<BDB> module: Each BDB
request that could block and doesn't get passed a callback will normally
block all coroutines. after loading this module, this will no longer be
the case (it provides a suitable sync prepare callback).

It will also register an AnyEvent watcher as soon as AnyEvent chooses an
event loop.

The AnyEvent watcher can be disabled by executing C<undef
$Coro::BDB::WATCHER>. Please notify the author of when and why you think
this was necessary.

This module does not export anything (unlike L<Coro::AIO>), as BDB already
supports leaving out the callback.

=over 4

=cut

package Coro::BDB;

no warnings;
use strict;

use Coro ();
use AnyEvent::BDB ();
use BDB ();

use base Exporter::;

our $VERSION = 4.749;
our $WATCHER;

BDB::set_sync_prepare {
   my $status;
   my $current = $Coro::current;
   (
      sub {
         $status = $!;
         $current->ready; undef $current;
      },
      sub {
         Coro::schedule while defined $current;
         $! = $status;
      },
   )
};

=back

=head1 SEE ALSO

L<BDB> of course.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

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