CONTENTS

• NAME
• SYNOPSIS
• DESCRIPTION
• CONSTRUCTOR
• METHODS
• NOTE
• SEE ALSO
• BUGS
• HISTORY

#NAME

IO::Handle - supply object methods for I/O handles

#SYNOPSIS

use IO::Handle;

$io = IO::Handle->new();
if ($io->fdopen(fileno(STDIN),"r")) {
    print $io->getline;
    $io->close;
}

$io = IO::Handle->new();
if ($io->fdopen(fileno(STDOUT),"w")) {
    $io->print("Some text\n");
}

# setvbuf is not available by default on Perls 5.8.0 and later.
use IO::Handle '_IOLBF';
$io->setvbuf($buffer_var, _IOLBF, 1024);

undef $io;       # automatically closes the file if it's open

autoflush STDOUT 1;

#DESCRIPTION

IO::Handle is the base class for all other IO handle classes. It is not intended that objects of IO::Handle would be created directly, but instead IO::Handle is inherited from by several other classes in the IO hierarchy.

If you are reading this documentation, looking for a replacement for the FileHandle package, then I suggest you read the documentation for IO::File too.

#CONSTRUCTOR

#new ()

Creates a new IO::Handle object.

#new_from_fd ( FD, MODE )

Creates an IO::Handle like new does. It requires two parameters, which are passed to the method fdopen; if the fdopen fails, the object is destroyed. Otherwise, it is returned to the caller.

#METHODS

See perlfunc for complete descriptions of each of the following supported IO::Handle methods, which are just front ends for the corresponding built-in functions:

$io->close
$io->eof
$io->fcntl( FUNCTION, SCALAR )
$io->fileno
$io->format_write( [FORMAT_NAME] )
$io->getc
$io->ioctl( FUNCTION, SCALAR )
$io->read ( BUF, LEN, [OFFSET] )
$io->print ( ARGS )
$io->printf ( FMT, [ARGS] )
$io->say ( ARGS )
$io->stat
$io->sysread ( BUF, LEN, [OFFSET] )
$io->syswrite ( BUF, [LEN, [OFFSET]] )
$io->truncate ( LEN )

See perlvar for complete descriptions of each of the following supported IO::Handle methods. All of them return the previous value of the attribute and takes an optional single argument that when given will set the value. If no argument is given the previous value is unchanged (except for $io->autoflush will actually turn ON autoflush by default).

$io->autoflush ( [BOOL] )                         $|
$io->format_page_number( [NUM] )                  $%
$io->format_lines_per_page( [NUM] )               $=
$io->format_lines_left( [NUM] )                   $-
$io->format_name( [STR] )                         $~
$io->format_top_name( [STR] )                     $^
$io->input_line_number( [NUM])                    $.

The following methods are not supported on a per-filehandle basis.

IO::Handle->format_line_break_characters( [STR] ) $:
IO::Handle->format_formfeed( [STR])               $^L
IO::Handle->output_field_separator( [STR] )       $,
IO::Handle->output_record_separator( [STR] )      $\

IO::Handle->input_record_separator( [STR] )       $/

Furthermore, for doing normal I/O you might need these:

#$io->fdopen ( FD, MODE )

fdopen is like an ordinary open except that its first parameter is not a filename but rather a file handle name, an IO::Handle object, or a file descriptor number. (For the documentation of the open method, see