-=item -B E<lt>capture buffer size (Win32 only)E<gt>
-
-Win32 only: set capture buffer size (in MB, default is 1MB). This is used by the
-the capture driver to buffer packet data until that data can be written to
-disk. If you encounter packet drops while capturing, try to increase this size.
+=item -B E<lt>capture buffer sizeE<gt>
+
+Set capture buffer size (in MB, default is 1MB). This is used by the
+the capture driver to buffer packet data until that data can be written
+to disk. If you encounter packet drops while capturing, try to increase
+this size. Note that, while B<Tshark> attempts to set the buffer size
+to 1MB by default, and can be told to set it to a larger value, the
+system or interface on which you're capturing might silently limit the
+capture buffer size to a lower value or raise it to a higher value.
+
+This is available on on UNIX systems with libpcap 1.0.0 or later and on
+Windows. It is not available on UNIX systems with earlier versions of
+libpcap.