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FileHandle(3pm)	       Perl Programmers Reference Guide	       FileHandle(3pm)

NAME
       FileHandle - supply object methods for filehandles

SYNOPSIS
	   use FileHandle;

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

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

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

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

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

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

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

	   autoflush STDOUT 1;

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 white‐
       space 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.

       "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 "File‐
       Handle::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.

       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 parame‐
       ter specifies a scalar variable to use as a buffer.  WARNING: A vari‐
       able 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!

       See perlfunc for complete descriptions of each of the following sup‐
       ported "FileHandle" methods, which are just front ends for the corre‐
       sponding built-in functions:

	   close
	   fileno
	   getc
	   gets
	   eof
	   clearerr
	   seek
	   tell

       See perlvar for complete descriptions of each of the following sup‐
       ported "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

       Furthermore, for doing 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.

       There are many other functions available since FileHandle is descended
       from IO::File, IO::Seekable, and IO::Handle.  Please see those respec‐
       tive pages for documentation on more functions.

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

perl v5.8.8			  2001-09-21		       FileHandle(3pm)
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