our($VERSION, @ISA, @EXPORT, @EXPORT_OK);
@EXPORT = qw(_IOFBF _IOLBF _IONBF);
format_line_break_characters
# Everything we're willing to export, we must first import.
import IO
::Handle
grep { !defined(&$_) } @EXPORT, @EXPORT_OK;
# Some people call "FileHandle::function", so all the functions
# that were in the old FileHandle class must be imported, too.
[qw(DESTROY new_from_fd fdopen close fileno getc ungetc gets
eof flush error clearerr setbuf setvbuf _open_mode_string)],
[qw(seek tell getpos setpos)],
[qw(new new_tmpfile open)]
for my $pkg (keys %import) {
for my $func (@
{$import{$pkg}}) {
my $c = *{"${pkg}::$func"}{CODE
}
or die "${pkg}::$func missing";
# Specialized importer for Fcntl magic.
Exporter
::export
($pkg, $callpkg, @_);
# If the Fcntl extension is available,
Exporter
::export
('Fcntl', $callpkg);
################################################
# This is the only exported function we define;
# the rest come from other classes.
CORE
::pipe($r, $w) or return undef;
# Rebless standard file handles
bless *STDIN
{IO
}, "FileHandle" if ref *STDIN
{IO
} eq "IO::Handle";
bless *STDOUT
{IO
}, "FileHandle" if ref *STDOUT
{IO
} eq "IO::Handle";
bless *STDERR
{IO
}, "FileHandle" if ref *STDERR
{IO
} eq "IO::Handle";
FileHandle - supply object methods for filehandles
if ($fh->open("< file")) {
$fh = new FileHandle "> FOO";
$fh = new FileHandle "file", "r";
undef $fh; # automatically closes the file
$fh = new FileHandle "file", O_WRONLY|O_APPEND;
undef $fh; # automatically closes the file
$fh->setvbuf($buffer_var, _IOLBF, 1024);
($readfh, $writefh) = FileHandle::pipe;
NOTE: This class is now a front-end to the IO::* classes.
C<FileHandle::new> creates a C<FileHandle>, which is a reference to a
newly created symbol (see the C<Symbol> package). If it receives any
parameters, they are passed to C<FileHandle::open>; if the open fails,
the C<FileHandle> object is destroyed. Otherwise, it is returned to
C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does.
It requires two parameters, which are passed to C<FileHandle::fdopen>;
if the fdopen fails, the C<FileHandle> object is destroyed.
Otherwise, it is returned to the caller.
C<FileHandle::open> accepts one parameter or two. With one parameter,
it is just a front end for the built-in C<open> function. With two
parameters, the first parameter is a filename that may include
whitespace or other special characters, and the second parameter is
the open mode, optionally followed by a file permission value.
If C<FileHandle::open> receives a Perl mode string (">", "+<", etc.)
or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
If C<FileHandle::open> is given a numeric mode, it passes that mode
and the optional permissions value to the Perl C<sysopen> operator.
For convenience, C<FileHandle::import> tries to import the O_XXX
constants from the Fcntl module. If dynamic loading is not available,
this may fail, but the rest of FileHandle will still work.
C<FileHandle::fdopen> is like C<open> except that its first parameter
is not a filename but rather a file handle name, a FileHandle object,
or a file descriptor number.
If the C functions fgetpos() and fsetpos() are available, then
C<FileHandle::getpos> returns an opaque value that represents the
current position of the FileHandle, and C<FileHandle::setpos> uses
that value to return to a previously visited position.
If the C function setvbuf() is available, then C<FileHandle::setvbuf>
sets the buffering policy for the FileHandle. The calling sequence
for the Perl function is the same as its C counterpart, including the
macros C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer
parameter specifies a scalar variable to use as a buffer. WARNING: A
variable used as a buffer by C<FileHandle::setvbuf> must not be
modified in any way until the FileHandle is closed or until
C<FileHandle::setvbuf> is called again, or memory corruption may
See L<perlfunc> for complete descriptions of each of the following
supported C<FileHandle> methods, which are just front ends for the
corresponding built-in functions:
See L<perlvar> for complete descriptions of each of the following
supported C<FileHandle> methods:
format_line_break_characters
Furthermore, for doing normal I/O you might need these:
This works like <$fh> described in L<perlop/"I/O Operators">
except that it's more readable and can be safely called in a
list context but still returns just one line.
This works like <$fh> when called in a list context to
read all the remaining lines in a file, except that it's more readable.
It will also croak() if accidentally called in a scalar context.
There are many other functions available since FileHandle is descended
from IO::File, IO::Seekable, and IO::Handle. Please see those
respective pages for documentation on more functions.
L<perlop/"I/O Operators">.