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Environ Function

Returns the string associated with an operating system environment variable.

Overloads Function Environ(ByVal Expression As Integer) As String


Overloads Function Environ(ByVal Expression As String) As String


Required. Expression that evaluates to either a string containing the name of an environment variable, or an integer corresponding to the numeric order of an environment string in the environment-string table.


Exception type Error number Condition
ArgumentException 5 Expression is missing.


If Expression contains a string, the Environ function returns the text assigned to the specified environment string; that is, the text following the equal sign (=) in the environment-string table for that environment variable. If the string in Expression cannot be found in the environment-string table, a zero-length string ("") is returned.

If Expression contains an integer, the string occupying that numeric position in the environment-string table is returned. In this case, Environ returns all of the text, including the name of the environment variable. If there is no environment string in the specified position, Environ returns a zero-length string.


This example uses the Environ function to supply the entry number and length of the PATH statement from the environment-string table.

Sub tenv()
   Dim envString As String
   Dim found As Boolean = False
   Dim index As Integer = 1
   Dim pathLength As Integer
   Dim message As String

   envString = Environ(index)
   While Not found And (envString <> "")
      If (envString.Substring(0, 5) = "Path=") Then
         found = True
         index += 1
         envString = Environ(index)
      End If
   End While

   If found Then
      pathLength = Environ("PATH").Length
      message = "PATH entry = " & index & " and length = " & pathLength
      message = "No PATH environment variable exists."
   End If

End Sub

Smart Device Developer Notes

This function is not supported.


Namespace: Microsoft.VisualBasic

Module: Interaction

Assembly: Microsoft Visual Basic .NET Runtime (in MicrosoftVisualBasic.dll)

See Also

Visual Basic Run-Time Library Members | ArgumentException Class