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

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

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

	# read data
	<$io>;
	$io->getline;
	read($io, $buf, 100);

	# write data
	print $io "string\n";
	$io->print(@data);
	syswrite($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);

DESCRIPTION
       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
       $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.

       $io->string_ref
	   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
       $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
       $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().

BUGS
       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.

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

COPYRIGHT
       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 v5.16.3				    2005-12-05					String(3)
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