phpman > perldoc > IO::String(3pm)

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.