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RedHat 9 (Linux i386) - man page for filehandle (redhat section 3pm)

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 "FileHan-
       dle::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 parame-
       ters, 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 file-
       name 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 per-
       missions 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 "File-
       Handle::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 buf-
       fer 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 v5.8.0				    2002-06-01				  FileHandle(3pm)


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