The man page says:

     -c count
             Stop after sending count ECHO_REQUEST packets. With deadline
op-
             tion, ping waits for count ECHO_REPLY packets, until the
timeout
             expires.

However, if you mix the -f flag with -c, it appears to *not* count
ECHO_REQUEST, and only counts ECHO_REPLY. This is bad because if you use -f
and -c on a host that's unreachable, it doesn't stop at #count and keeps
flood pinging forever. It is as if it implies a -w with an infinite value.

Specifying the -w deadline option with a reasonable value works with -f and
-c fine.

Examples ->

This is fine:
# ping -c 50 -n www.microsoft.com
PING www.microsoft.akadns.net (207.46.230.229) from 64.22.132.134 : 56(84)
bytes of data.

--- www.microsoft.akadns.net ping statistics ---
50 packets transmitted, 0 packets received, 100% packet loss


This is ok, but it sent 53 packets though I asked to send only 50:
# ping -f -c 50 -n www.yahoo.com
PING www.yahoo.akadns.net (204.71.200.75) from 64.22.132.134 : 56(84) bytes
of data.
....
--- www.yahoo.akadns.net ping statistics ---
53 packets transmitted, 50 packets received, 5% packet loss
round-trip min/avg/max/mdev = 18.959/19.612/22.615/0.688 ms

But this is not fine:
# ping -f -c 5 -n www.microsoft.com
PING www.microsoft.akadns.net (207.46.230.229) from 64.22.132.134 : 56(84)
bytes of data.
...................................................................................................................................................................................................................................................................................................................................................................................................................................................^C
--- www.microsoft.akadns.net ping statistics ---
435 packets transmitted, 0 packets received, 100% packet loss

# ping -f -c 5 -n 10.50.1.10       
Warning: no SO_TIMESTAMP support, falling back to SIOCGSTAMP
PING 10.50.1.10 (10.50.1.10) from 24.130.93.25 : 56(84) bytes of data.
Warning: no SO_RCVTIMEO support, falling back to poll
.................E.................E..................................E.................E..................................E.................E.................E.................E.................E.................E.................E.................E.................E.................E.................E.................E..................................E.................E.................E.................E.................E.................E.................E.................E.................E.................E.................................E.................E.................E.................E...................E................................E................E.................E.................E.................E.................E.................E...................................................E.................E......................E..............................................E..................................E.................E.................E.................E.................E.................E.................E..................................E.................E...................................E................E.................E.................E.................E...................................................E...................................................E.................E...................................................E..................................E.................E.................E.................E..................................E.................E.................E..................E................E.................E.................E.................E.................E.................E.................E..................................E.................E.................E..................................E.................E.................E..................................E..................................E..................E...................................................................................E................E.................E.................................E...................................................E.................E.................E.................E..................................E.................E.................E..................................E.................E.................E.................E.................E..................................E..................................................E.................E.................E.................E.................E.................E.................E.................E..................................................E.................E.................E.................E.................E.................E..................E......................^C
--- 10.50.1.10 ping statistics ---
2750 packets transmitted, 0 packets received, +116 errors, 100% packet loss



This appears to have been broken for quite some time.