Script Tips

Recycling: It's Good for the Script

Modularize your VBScripts with subs and functions.

• By Don Jones
• 05/08/2006

Function TestPing(sName)
Dim cPingResults, oPingResult
Set cPingResults = _
  GetObject("winmgmts://./root/cimv2").ExecQuery(_
  "SELECT * FROM Win32_PingStatus WHERE Address = '"_
  & sName & "'")
On Error Resume Next
For Each oPingResult In cPingResults
  If oPingResult Is Null Then
   TestPing = False
  ElseIf oPingResult.StatusCode = 0 Then
   TestPing = True
  Else
   TestPing = False
  End If
Next
End Function

Here what this function does:

• It declares an argument, strComputer, which will hold the function's input. The function doesn't rely on any data apart from this argument, thus making the function entirely self-contained.
• The function returns a result, either True or False, by setting the function's name equal to whatever value is to be returned.
• The function doesn't reference any variables apart from those declared within the function itself.
• The strComputer argument works like a variable, but doesn't need to be declared using the Dim keyword-it's declared as a part of the function itself.

By the way, this will only run on WinXP and Win2003 boxes, and it'll give you a True or False if the computer you specify that it's pingable or not. Use this function like this:

If TestPing("server1") Then
  'is available
Else
  'is not pingable
End If

By keeping the TestPing() function self-contained, it can be easily pasted into any script where you need to use it. That's the real goal of Subs and Functions: to modularize and encapsulate code so that it can be more easily reused. Reusing code saves time, so it's a good habit to practice.