FileHandle man page on aLinux

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

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
       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.

       "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.

       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!

       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

       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

       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
       respective pages for documentation on more functions.

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

perl v5.10.0			  2007-12-18			 FileHandle(3)
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