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Perl Language Reference Manual
by Larry Wall and others
Paperback (6"x9"), 724 pages
ISBN 9781906966027
RRP £29.95 ($39.95)

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tell FILEHANDLE

tell

Returns the current position in bytes for FILEHANDLE, or -1 on error. FILEHANDLE may be an expression whose value gives the name of the actual filehandle. If FILEHANDLE is omitted, assumes the file last read.

Note the in bytes: even if the filehandle has been set to operate on characters (for example by using the :encoding(utf8) open layer), tell() will return byte offsets, not character offsets (because that would render seek() and tell() rather slow).

The return value of tell() for the standard streams like the STDIN depends on the operating system: it may return -1 or something else. tell() on pipes, fifos, and sockets usually returns -1.

There is no systell function. Use sysseek(FH, 0, 1) for that.

Do not use tell() (or other buffered I/O operations) on a filehandle that has been manipulated by sysread(), syswrite() or sysseek(). Those functions ignore the buffering, while tell() does not.

ISBN 9781906966027Perl Language Reference ManualSee the print edition