NAME
IO::Handle::Record - IO::Handle extension to pass perl data structures
SYNOPSIS
use IO::Socket::UNIX;
use IO::Handle::Record;
($p, $c)=IO::Socket::UNIX->socketpair( AF_UNIX,
SOCK_STREAM,
PF_UNSPEC );
while( !defined( $pid=fork ) ) {sleep 1}
if( $pid ) {
close $c; undef $c;
$p->record_opts={send_CODE=>1};
$p->write_record( {a=>'b', c=>'d'},
sub { $_[0]+$_[1] },
[qw/this is a test/] );
} else {
close $p; undef $p;
$c->record_opts={receive_CODE=>sub {eval $_[0]}};
($hashref, $coderef, $arrayref)=$c->read_record;
}
DESCRIPTION
IO::Handle::Record
extends the IO::Handle
class. Since many classes derive from IO::Handle
these extensions can be used with IO::File
, IO::Socket
, IO::Pipe
, etc.
The methods provided read and write lists of perl data structures. They can pass anything that can be serialized with Storable
even subroutines between processes.
The following methods are added:
- $handle->record_opts
-
This lvalue method expects a hash reference with options as parameter. The
send_CODE
andreceive_CODE
options are defined. They correspond to localized versions of$Storable::Deparse
and$Storable::Eval
respectively. See the Storable manpage for further information.Example:
$handle->record_opts={send_CODE=>1, receive_CODE=>1};
- $handle->write_record(@data)
-
writes a list of perl data structures.
write_record
returns 1 if the record has been transmitted.undef
is returned if$handle
is non blocking and a EAGAIN condition is met. In this case reinvoke the operation without parameters (just$handle->write_record
) when the handle becomes ready. Otherwise it throws an exceptionIO::Handle::Record: syswrite error
. Check$!
in this case.EINTR is handled internally.
Example:
$handle->write_record( [1,2], sub {$_[0]+$_[1]}, { list=>[1,2,3], hash=>{a=>'b'}, code=>sub {print "test\n";} } );
- @data=$handle->read_record
-
reads one record of perl data structures.
On success it returns the record as list. An empty list is returned if
$handle
is in non blocking mode and not enough data has been read. Check $!==EAGAIN to catch this condition. When the handle becomes ready just repeat the operation to read the next data chunk. If a complete record has arrived it is returned.On EOF an empty list is returned. To distinguish this from the non blocking empty list return set
$!=0
before the operation and check for$!==EAGAIN
after.EINTR is handled internally.
Example:
($array, $sub, $hash)=$handle->read_record;
- $handle->read_buffer =item $handle->expected =item $handle->write_buffer =item $handle->written
-
these methods are used internally to provide a read and write buffer for non blocking operations.
EXPORT
None.
SEE ALSO
IO::Handle
AUTHOR
Torsten Foertsch, <torsten.foertsch@gmx.net<gt>
COPYRIGHT AND LICENSE
Copyright (C) 2005 by Torsten Foertsch
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.