Examples: Using environment variables

This button example increments the environment variable $SeqNo by one and prints the result. (This script would not be reliable on a server for maintaining a system of sequential numbers.)

Sub Click(Source As Button)
  Dim session As New NotesSession
  seqNo = session.GetEnvironmentValue("SeqNo")
  If Isempty(seqNo) Then
    Call session.SetEnvironmentVar("SeqNo", 1)
  Else
    seqNo = seqNo + 1
    Call session.SetEnvironmentVar _
    ("SeqNo", Cint(seqNo))
  End If
  Messagebox session.GetEnvironmentValue("SeqNo")
End Sub

This agent example prints the value of a system environment variable. GetEnvironmentString is used to accept an environment variable that is either a number or a string. The second argument to GetEnvironmentString is true so that a dollar sign is not prepended to the name of the environment variable.
```
Sub Initialize
  Dim session As New NotesSession
  envVarName = Inputbox$("Environment variable name")
  envVar = session.GetEnvironmentString(envVarName, _
  True)
  If envVar = "" Then
    Messagebox(envVarName & " not set")
  Else
    Messagebox(envVarName & " = " & envVar)
  End If
End Sub
```