IO::Seekable - supply seek based methods for I/O objects
use IO::Seekable; package IO::Something; @ISA = qw(IO::Seekable);
Perl Programmers Reference Guide IO::Seekable(3) 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. ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+-----------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+-----------------------+ |Availability | runtime/perl-532 | +---------------+-----------------------+ |Stability | Pass-through volatile | +---------------+-----------------------+ SEE ALSO perlfunc, "I/O Operators" in perlop, IO::Handle IO::File HISTORY Derived from FileHandle.pm by Graham Barr <gbarr@pobox.com> NOTES Source code for open source software components in Oracle Solaris can be found at https://www.oracle.com/downloads/opensource/solaris-source- code-downloads.html. This software was built from source available at https://github.com/oracle/solaris-userland. The original community source was downloaded from http://www.cpan.org/src/5.0/perl-5.32.0.tar.gz. Further information about this software can be found on the open source community website at https://www.perl.org/. perl v5.32.0 2020-06-14 IO::Seekable(3)