dynamic(3)						User Contributed Perl Documentation						dynamic(3)

NAME

       PerlIO::via::dynamic - dynamic PerlIO layers

SYNOPSIS

	open $fh, $fname;
	$p = PerlIO::via::dynamic->new
	 (translate =>
	   sub { $_[1] =~ s/$Filename[:ws-./\]*$/$Filename: $fname$/e},
	  untranslate =>
	   sub { $_[1] =~ s/$Filename[:ws-./\]*$/$Filename$/});
	$p->via ($fh);
	binmode $fh, $p->via; # deprecated

DESCRIPTION

       "PerlIO::via::dynamic" is used for creating dynamic PerlIO layers. It is useful when the behavior or the layer depends on variables. You
       should not use this module as via layer directly (ie :via(dynamic)).

       Use the constructor to create new layers, with two arguments: translate and untranslate. Then use "$p-"via ($fh)> to wrap the handle.  Once
       <$fh> is destroyed, the temporary namespace for the IO layer will be removed.

       Note that PerlIO::via::dynamic uses the scalar fields to reference to the object representing the dynamic namespace.

OPTIONS

       translate
	   A function that translate buffer upon write.

       untranslate
	   A function that translate buffer upon read.

       use_read
	   Use "READ" instead of "FILL" for the layer.	Useful when caller expect exact amount of data from read, and the "untranslate" function
	   might return different length.

	   By default "PerlIO::via::dynamic" creates line-based layer to make "translate" implementation easier.

AUTHORS

       Chia-liang Kao <clkao@clkao.org>

COPYRIGHT

       Copyright 2004 by Chia-liang Kao <clkao@clkao.org>.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

       See <http://www.perl.com/perl/misc/Artistic.html>

perl v5.16.2							    2008-05-31								dynamic(3)