程序代码：

Function VfpPing
Lparameters tcWhere, tnWhichPort
Local lReturnValue

* [color=#0000FF]by josh@jassing.com[/color]
* [color=#0000FF]with LOTS of help from (actually; all the hard work by) Markus Voellmy[/color]
* wrapped up [color=#0000FF]as a big function by Lou Harris[/color]
*
* ? pingstate( pingx( "www.,[color=#800000]80 ) )[/color]
* would [color=#0000FF]check  to be sure it's running a web server
* NOTE: it does not do any dns lookups; so if you[/color]'re checking for a mail server, you need
* [color=#0000FF]to resolve the mx record yourself.[/color]

If Vartype(tnWhichPort) # "N"
   tnWhichPort = 80
Endif
*? pingstate( pingx( "www.,80 ) )
lReturnValue = pingstate( pingx( m.tcWhere, m.tnWhichPort ) )
Return m.lReturnValue

#Define sckClosed 0
#Define sckOpen 1
#Define sckListening 2
#Define sckConnectionPending 3
#Define sckResolvingHost 4
#Define sckHostResolved 5
#Define sckConnecting 6
#Define sckConnected 7
#Define sckClosing 8
#Define sckError 9
Endfunc

Function pingstate
Lparameters tnState
Local lcState
Do Case
Case tnState = sckClosed
   lcState = "Closed"
Case tnState = sckOpen
   lcState = "Open"
Case tnState = sckListening
   lcState = "Listening"
Case tnState = sckConnectionPending
   lcState = "Waiting"
Case tnState = sckResolvingHost
   lcState = "Resolving"
Case tnState = sckConnecting
   lcState = "Connecting"
Case tnState = sckConnected
   lcState = "Connected"
Case tnState = sckClosing
   lcState = "Closing"
Case tnState = sckError
   lcState = "Error"
Otherwise
   lcState = "Unknown"
Endcase
Return lcState
Endfunc

Function pingx
Lparameters tcServer, tnPort
Local lnState, loPing, lnLast
loPing=Createobject("mswinsck.winsock")
With loPing
   .remoteport = tnPort
   .remotehost = tcServer
   .Connect()
   lnLast = -1
   Do While .state < sckConnected
      If lnLast # .state
         lnLast = .state
      Endif
   Enddo
   lnState = .state
   .Close()
Endwith
Return lnState