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String(3)	      User Contributed Perl Documentation	     String(3)

       IO::String - Emulate file interface for in-core strings

	use IO::String;
	$io = IO::String->new;
	$io = IO::String->new($var);
	tie *IO, 'IO::String';

	# read data
	read($io, $buf,	100);

	# write	data
	print $io "string\n";
	syswrite($io, $buf, 100);

	select $io;
	printf "Some text %s\n", $str;

	# seek
	$pos = $io->getpos;
	$io->setpos(0);	       # rewind
	$io->seek(-30, -1);
	seek($io, 0, 0);

       The "IO::String"	module provides	the "IO::File" interface for in-core
       strings.	 An "IO::String" object	can be attached	to a string, and makes
       it possible to use the normal file operations for reading or writing
       data, as	well as	for seeking to various locations of the	string.	 This
       is useful when you want to use a	library	module that only provides an
       interface to file handles on data that you have in a string variable.

       Note that perl-5.8 and better has built-in support for "in memory"
       files, which are	set up by passing a reference instead of a filename to
       the open() call.	The reason for using this module is that it makes the
       code backwards compatible with older versions of	Perl.

       The "IO::String"	module provides	an interface compatible	with
       "IO::File" as distributed with IO-1.20, but the following methods are
       not available: new_from_fd, fdopen, format_write, format_page_number,
       format_lines_per_page, format_lines_left, format_name, format_top_name.

       The following methods are specific to the "IO::String" class:

       $io = IO::String->new
       $io = IO::String->new( $string )
	   The constructor returns a newly-created "IO::String"	object.	 It
	   takes an optional argument, which is	the string to read from	or
	   write into.	If no $string argument is given, then an internal
	   buffer (initially empty) is allocated.

	   The "IO::String" object returned is tied to itself.	This means
	   that	you can	use most Perl I/O built-ins on it too: readline, <>,
	   getc, print,	printf,	syswrite, sysread, close.

       $io->open( $string )
	   Attaches an existing	IO::String object to some other	$string, or
	   allocates a new internal buffer (if no argument is given).  The
	   position is reset to	0.

	   Returns a reference to the string that is attached to the
	   "IO::String"	object.	 Most useful when you let the "IO::String"
	   create an internal buffer to	write into.

       $io->pad( $char )
	   Specifies the padding to use	if the string is extended by either
	   the seek() or truncate() methods.  It is a single character and
	   defaults to "\0".

       $io->pos( $newpos )
	   Yet another interface for reading and setting the current
	   read/write position within the string (the normal
	   getpos/setpos/tell/seek methods are also available).	 The pos()
	   method always returns the old position, and if you pass it an
	   argument it sets the	new position.

	   There is (deliberately) a difference	between	the setpos() and
	   seek() methods in that seek() extends the string (with the
	   specified padding) if you go	to a location past the end, whereas
	   setpos() just snaps back to the end.	 If truncate() is used to
	   extend the string, then it works as seek().

       In Perl versions	< 5.6, the TIEHANDLE interface was incomplete.	If you
       use such	a Perl,	then seek(), tell(), eof(), fileno(), binmode()	will
       not do anything on an "IO::String" handle.  See perltie for details.

       IO::File, IO::Stringy, "open" in	perlfunc

       Copyright 1998-2005 Gisle Aas.

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

perl v5.32.1			  2005-12-05			     String(3)


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