--- IO-AIO/AIO.pm	2010/01/10 23:10:58	1.178
+++ IO-AIO/AIO.pm	2010/01/10 23:44:01	1.179
@@ -1582,6 +1582,9 @@
 
 If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
 
+C<$offset> is the offset from the start of the file - it generally must be
+a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
+
 Example:
 
    use Digest::MD5;