=head1 NAME

Coro::Specific - manage coroutine-specific variables.

=head1 SYNOPSIS

 use Coro::Specific;

 my $ref = new Coro::Specific;

 $$ref = 5;
 print $$ref;

=head1 DESCRIPTION

This module can be used to create variables (or better: references to
them) that are specific to the currently executing coroutine. This module
does not automatically load the Coro module (so the overhead will be small
when no coroutines are used).

A much faster method is to store extra keys into C<%$Coro::current>
- all you have to do is to make sure that the key is unique (e.g. by
prefixing it with your module name). You can even store data there before
loading the L<Coro> module - when Coro is loaded, the keys stored in
C<%$Coro::current> are automatically attached to the coro thread executing
the main program.

You don't have to load C<Coro::Specific> manually, it will be loaded
automatically when you C<use Coro> and call the C<new> constructor.

=over 4

=cut

package Coro::Specific;

use common::sense;

our $VERSION = 6.57;

=item new

Create a new coroutine-specific scalar and return a reference to it. The
scalar is guaranteed to be "undef". Once such a scalar has been allocated
you cannot deallocate it (yet), so allocate only when you must.

=cut

my $idx;

sub new {
   my $var;
   tie $var, Coro::Specific::;
   \$var;
}

sub TIESCALAR {
   my $idx = $idx++;
   bless \$idx, $_[0];
}

sub FETCH {
   $Coro::current->{_specific}[${$_[0]}];
}

sub STORE {
   $Coro::current->{_specific}[${$_[0]}] = $_[1];
}

#sub DESTROY {
#   push @idx, $$_[0];
#}

1;

=back

=head1 BUGS

The actual coroutine specific values do not automatically get destroyed
when the Coro::Specific object gets destroyed.

=head1 AUTHOR/SUPPORT/CONTACT

   Marc A. Lehmann <schmorp@schmorp.de>
   http://software.schmorp.de/pkg/Coro.html

=cut