docs: adjust description for --print-tos

Every IPv4 packet has a TOS byte.  Every IPv6 packet has a TC byte.
But fping can only read it when using raw sockets, and only for IPv4.

diff --git a/doc/fping.pod b/doc/fping.pod
index 4bc15762aa7a7a79bdd482fc5183e1c8b545be53..3f4ac5f2766c0edb598e0031ba17c01597f4f886 100644 (file)
--- a/doc/fping.pod
+++ b/doc/fping.pod
@@ -188,7 +188,8 @@ Set the typ of service flag (TOS). I<N> can be either decimal or hexadecimal
 
 =item B<--print-tos>
 
-Displays the TOS value in the output, if TOS is not present, "(TOS unknown)" is returned.
+Displays the TOS value in the output. If B<fping> cannot read the TOS value,
+"(TOS unknown)" is returned.
 IPv4 only, requires root privileges or cap_net_raw.
 
 =item B<-p>, B<--period>=I<MSEC>