io5.18(3pm) [mojave man page]

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

NAME

       IO - load various IO modules

SYNOPSIS

	  use IO qw(Handle File); # loads IO modules, here IO::Handle, IO::File
	  use IO;		  # DEPRECATED

DESCRIPTION

       "IO" provides a simple mechanism to load several of the IO modules in one go.  The IO modules belonging to the core are:

	     IO::Handle
	     IO::Seekable
	     IO::File
	     IO::Pipe
	     IO::Socket
	     IO::Dir
	     IO::Select
	     IO::Poll

       Some other IO modules don't belong to the perl core but can be loaded as well if they have been installed from CPAN.  You can discover
       which ones exist by searching for "^IO::" on http://search.cpan.org.

       For more information on any of these modules, please see its respective documentation.

DEPRECATED

	   use IO;		  # loads all the modules listed below

       The loaded modules are IO::Handle, IO::Seekable, IO::File, IO::Pipe, IO::Socket, IO::Dir.  You should instead explicitly import the IO
       modules you want.

perl v5.18.2							    2014-01-06								   IO(3pm)

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 v5.12.1							    2010-04-26							 IO::Seekable(3pm)