io::seekable(3pm) [centos man page]

IO::Seekable(3pm)					 Perl Programmers Reference Guide					 IO::Seekable(3pm)

NAME

       IO::Seekable - supply seek based methods for I/O objects

SYNOPSIS

	   use IO::Seekable;
	   package IO::Something;
	   @ISA = qw(IO::Seekable);

DESCRIPTION

       "IO::Seekable" does not have a constructor of its own as it is intended to be inherited by other "IO::Handle" based objects. It provides
       methods which allow seeking of the file descriptors.

       $io->getpos
	   Returns an opaque value that represents the current position of the IO::File, or "undef" if this is not possible (eg an unseekable
	   stream such as a terminal, pipe or socket). If the fgetpos() function is available in your C library it is used to implements getpos,
	   else perl emulates getpos using C's ftell() function.

       $io->setpos
	   Uses the value of a previous getpos call to return to a previously visited position. Returns "0 but true" on success, "undef" on
	   failure.

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

       $io->seek ( POS, WHENCE )
	   Seek the IO::File to position POS, relative to WHENCE:

	   WHENCE=0 (SEEK_SET)
		   POS is absolute position. (Seek relative to the start of the file)

	   WHENCE=1 (SEEK_CUR)
		   POS is an offset from the current position. (Seek relative to current)

	   WHENCE=2 (SEEK_END)
		   POS is an offset from the end of the file. (Seek relative to end)

	   The SEEK_* constants can be imported from the "Fcntl" module if you don't wish to use the numbers 0 1 or 2 in your code.

	   Returns 1 upon success, 0 otherwise.

       $io->sysseek( POS, WHENCE )
	   Similar to $io->seek, but sets the IO::File's position using the system call lseek(2) directly, so will confuse most perl IO operators
	   except sysread and syswrite (see perlfunc for full details)

	   Returns the new position, or "undef" on failure.  A position of zero is returned as the string "0 but true"

       $io->tell
	   Returns the IO::File's current position, or -1 on error.

SEE ALSO

       perlfunc, "I/O Operators" in perlop, IO::Handle IO::File

HISTORY

       Derived from FileHandle.pm by Graham Barr <gbarr@pobox.com>

perl v5.16.3							    2013-02-26							 IO::Seekable(3pm)

IO::File(3pm)						 Perl Programmers Reference Guide					     IO::File(3pm)

NAME

       IO::File - supply object methods for filehandles

SYNOPSIS

	   use IO::File;

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

	   $fh = IO::File->new("> file");
	   if (defined $fh) {
	       print $fh "bar
";
	       $fh->close;
	   }

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

	   $fh = IO::File->new("file", O_WRONLY|O_APPEND);
	   if (defined $fh) {
	       print $fh "corge
";

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

	       undef $fh;	# automatically closes the file
	   }

	   autoflush STDOUT 1;

DESCRIPTION

       "IO::File" inherits from "IO::Handle" and "IO::Seekable". It extends these classes with methods that are specific to file handles.

CONSTRUCTOR

       new ( FILENAME [,MODE [,PERMS]] )
	   Creates an "IO::File".  If it receives any parameters, they are passed to the method "open"; if the open fails, the object is
	   destroyed.  Otherwise, it is returned to the caller.

       new_tmpfile
	   Creates an "IO::File" opened for read/write on a newly created temporary file.  On systems where this is possible, the temporary file
	   is anonymous (i.e. it is unlinked after creation, but held open).  If the temporary file cannot be created or opened, the "IO::File"
	   object is destroyed.  Otherwise, it is returned to the caller.

METHODS

       open( FILENAME [,MODE [,PERMS]] )
       open( FILENAME, IOLAYERS )
	   "open" accepts one, two or three parameters.  With one parameter, it is just a front end for the built-in "open" function.  With two or
	   three 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 "IO::File::open" receives a Perl mode string (">", "+<", etc.)  or an ANSI C fopen() mode string ("w", "r+", etc.), it uses the
	   basic Perl "open" operator (but protects any special characters).

	   If "IO::File::open" is given a numeric mode, it passes that mode and the optional permissions value to the Perl "sysopen" operator.
	   The permissions default to 0666.

	   If "IO::File::open" is given a mode that includes the ":" character, it passes all the three arguments to the three-argument "open"
	   operator.

	   For convenience, "IO::File" exports the O_XXX constants from the Fcntl module, if this module is available.

       binmode( [LAYER] )
	   "binmode" sets "binmode" on the underlying "IO" object, as documented in "perldoc -f binmode".

	   "binmode" accepts one optional parameter, which is the layer to be passed on to the "binmode" call.

NOTE

       Some operating systems may perform  "IO::File::new()" or "IO::File::open()" on a directory without errors.  This behavior is not portable
       and not suggested for use.  Using "opendir()" and "readdir()" or "IO::Dir" are suggested instead.

SEE ALSO

       perlfunc, "I/O Operators" in perlop, IO::Handle, IO::Seekable, IO::Dir

HISTORY

       Derived from FileHandle.pm by Graham Barr <gbarr@pobox.com>.

perl v5.16.3							    2013-03-04							     IO::File(3pm)