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

# [NAME](#NAME)

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

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#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)](#WHENCE=0)

POS is absolute position. (Seek relative to the start of the file)

[WHENCE=1 (SEEK\_CUR)](#WHENCE=1)

POS is an offset from the current position. (Seek relative to current)

[WHENCE=2 (SEEK\_END)](#WHENCE=2)

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)](/man/os/perl/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](#SEE_ALSO)

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

# [HISTORY](#HISTORY)

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

2026-10-21 perl v5.44.0

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Document: IO::Seekable(3pm) from perl 5.44.0-r2 (Chainguard OS)
Source: https://github.com/Perl/perl5.git