=head1 NAME

overload::open - Hooks the native open function

=head1 SYNOPSIS

  use overload::open;
  my %opened_files;
  sub my_callback { return if !@_; $opened_files{shift}++ }
  overload::open->prehook_open(\&my_callback);
  open my $fh, '>', "foo.txt";

=head1 DESCRIPTION

This module hooks the native C<open()> and/or C<sysopen()> functions and passes the
arguments first to your function and then calls sends it
to the provided subroutine functions instead.
It does this using XS and replacing the OP_OPEN/OP_SYSOPEN opcode's with an XS
function. This function will call your provided sub, then once that returns
it will run the original OP.

=head1 FEATURES

This function will work fine if you call C<open> or C<sysopen> inside the callback
due to it detecting recursive calls and not calling the callback for recursive calls.

You are not allowed to pass XS subs as the callback because then this could result
in a recursive loop. If you need to do this, wrap the XS function in a native Perl
function.

=head1 METHODS

=over

=item prehook_open

  use overload::open
  overload::open->prehook_open(\&my_sub)

Runs a hook before C<open> by hooking C<OP_OPEN>. The provided sub reference
will be passed the same arguments as open.

=item prehook_sysopen

  use overload::open;
  overload::open->prehook_sysopen(\&my_sub)

Runs a hook before C<sysopen> by hooking C<OP_SYSOPEN>. Passes the same arguments
to the provided sub reference as provided to sysopen.

=back

=head1 AUTHOR

Samantha McVey <samantham@posteo.net>

=head1 LICENSE

This module is available under the same licences as perl, the Artistic license and the GPL.
