.\" Modified 2003-08-21 by Andries Brouwer <aeb@cwi.nl>
.\" 2011-09-18, mtk, Added SEEK_DATA + SEEK_HOLE
.\"
-.TH LSEEK 2 2011-09-25 "Linux" "Linux Programmer's Manual"
+.TH LSEEK 2 2013-03-27 "Linux" "Linux Programmer's Manual"
.SH NAME
lseek \- reposition read/write file offset
.SH SYNOPSIS
.\" https://lkml.org/lkml/2011/4/22/79
.\" http://lwn.net/Articles/440255/
.\" http://blogs.oracle.com/bonwick/entry/seek_hole_and_seek_data
+
+The
+.BR _GNU_SOURCE
+feature test macro must be defined in order to obtain the definitions of
+.BR SEEK_DATA
+and
+.BR SEEK_HOLE
+from
+.IR <unistd.h> .
.SH RETURN VALUE
Upon successful completion,
.BR lseek ()