.TH LSEEK 2 
.UC
.SH NAME
lseek, tell \- move read/write pointer
.SH SYNOPSIS
.B #include <sys/types.h>
.br
.B #include <sys/file.h>
.sp
.B long lseek(fildes, offset, whence)
.br
.B long offset;
.PP
.B long tell(fildes)
.SH DESCRIPTION
The file
descriptor refers to a file open for reading or writing.
The read (resp. write) pointer for the file is set as follows:
.IP
If
.I whence
is FSEEK_ABSOLUTE, the pointer is set to
.I offset
bytes.
.IP
If
.I whence
is FSEEK_RELATIVE, the pointer is set to its current location plus
.IR offset .
.IP
If
.I whence
is FSEEK_EOF, the pointer is set to the size of the
file plus
.IR offset .
.PP
The returned value is the resulting pointer location.
.PP
The obsolete function
.IR tell ( fildes )
is identical to
.IR lseek ( "fildes, 0L, FSEEK_RELATIVE" ).
.PP
Seeking far beyond the end of a file, then writing,
creates a gap or `hole', which occupies no
physical space and reads as zeros.
.SH RETURN VALUE
Upon successful completion, the new file offset returned.  Otherwise, a
value of \-1 is returned and
.I errno
is set to indicate the error.
.SH ERRORS
.I Lseek
will fail and the file pointer will remain unchanged if:
.TP 20
[EBADF]
.I Fildes
is not an open file descriptor.
.TP 20
[ESPIPE]
.I Fildes
is associated with a pipe.
.SH "SEE ALSO"
creat(2), open(2), fseek(3S)
.SH BUGS
.I Lseek
is a no-op on character special files.
No bounds check is made on
.IR offset .
It is permissible to seek past the end of
a file open only for reading.
.SH ASSEMBLER
(lseek = 19.)
.br
(file descriptor in r0)
.br
.B sys lseek; offset1; offset2; whence
.PP
.I Offset1
and
.I offset2
are the high and low words of 
.IR offset ;
r0 and r1 contain
the pointer upon return.