FileHandle(3pm)

💖 FileHandle(3pm) 💖

okay bestie, so this is the manual page for FileHandle — supply object methods for filehandles. yes it's FileHandle(3pm), from the Perl Programmers Reference Guide, and yes we're gonna get through it together 🫶

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✨ SYNOPSIS ✨

like, here's the vibe in code form, no notes:

use FileHandle;

my $fh = FileHandle->new;
if ($fh->open("< file")) {
    print <$fh>;
    $fh->close;
}

my $fh = FileHandle->new("> FOO");
if (defined $fh) {
    print $fh "bar\n";
    $fh->close;
}

my $fh = FileHandle->new("file", "r");
if (defined $fh) {
    print <$fh>;
    undef $fh;       # automatically closes the file
}

my $fh = FileHandle->new("file", O_WRONLY|O_APPEND);
if (defined $fh) {
    print $fh "corge\n";
    undef $fh;       # automatically closes the file
}

my $pos = $fh->getpos;
$fh->setpos($pos);

$fh->setvbuf(my $buffer_var, _IOLBF, 1024);

my ($readfh, $writefh) = FileHandle::pipe;

autoflush STDOUT 1;

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🦋 DESCRIPTION 🦋

💅 NOTE: This class is now a front-end to the IO::* classes.

FileHandle::new creates a FileHandle, which is a reference to a newly created symbol (see the Symbol package). If it receives any parameters, they are passed to FileHandle::open; if the open fails, the FileHandle object is destroyed. Otherwise, it is returned to the caller.

FileHandle::new_from_fd creates a FileHandle like new does. It requires two parameters, which are passed to FileHandle::fdopen; if the fdopen fails, the FileHandle object is destroyed. Otherwise, it is returned to the caller.

FileHandle::open accepts one parameter or two. With one parameter, it is just a front end for the built-in 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 FileHandle::open receives a Perl mode string (>, +<, etc.) or a POSIX fopen() mode string (w, r+, etc.), it uses the basic Perl open operator.

If FileHandle::open is given a numeric mode, it passes that mode and the optional permissions value to the Perl sysopen operator. For convenience, 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. (lowkey a little drama but we move 💀)

FileHandle::fdopen is like 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 FileHandle::getpos returns an opaque value that represents the current position of the FileHandle, and FileHandle::setpos uses that value to return to a previously visited position. bookmarking but make it posix ✨

If the C function setvbuf() is available, then 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 _IOFBF, _IOLBF, and _IONBF, except that the buffer parameter specifies a scalar variable to use as a buffer.

🚨 WARNING: A variable used as a buffer by FileHandle::setvbuf must not be modified in any way until the FileHandle is closed or until FileHandle::setvbuf is called again, or memory corruption may result! like for real for real, do not touch that buffer, it's giving haunted 👻

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🌸 the built-in front-ends 🌸

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

close
fileno
getc
gets
eof
clearerr
seek
tell

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🎀 the perlvar girlies 🎀

See perlvar for complete descriptions of each of the following supported FileHandle methods:

autoflush
output_field_separator
output_record_separator
input_record_separator
input_line_number
format_page_number
format_lines_per_page
format_lines_left
format_name
format_top_name
format_line_break_characters
format_formfeed

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💜 and for actual normal I/O, you might need these 💜

• $fh->print — See "print" in perlfunc.
• $fh->printf — See "printf" in perlfunc.
• $fh->getline — This works like <$fh> described in "I/O Operators" in perlop except that it's more readable and can be safely called in a list context but still returns just one line.
• $fh->getlines — This works like <$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. 😭 read the room, scalar context!

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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. it's giving family tree energy 👑

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🔥 SEE ALSO 🔥

The IO extension, perlfunc, "I/O Operators" in perlop.

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and that's the whole page, bestie — no cap, you ate that 🍓

mwah 💋 this was perl v5.42.3, dated 2026-11-03, and it's the FileHandle(3pm) page — go forth and handle files iconically ✨