Environ Function
Returns the string associated with an operating-system environment variable.
Overloads Function Environ(ByVal Expression As Integer) As String ' -or- Overloads Function Environ(ByVal Expression As String) As String
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Expression is missing. |
See the "Error number" column if you are upgrading Visual Basic 6.0 applications that use unstructured error handling. (You can compare the error number against the Number Property (Err Object).) However, when possible, you should consider replacing such error control with Structured Exception Handling Overview for Visual Basic.
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.
Security Note:
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The Environ function requires environment permission, which might affect its execution in partial-trust situations. For more information, see SecurityPermission and Code Access Permissions. |
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 Else index += 1 envString = Environ(index) End If End While If found Then pathLength = Environ("PATH").Length message = "PATH entry = " & index & " and length = " & pathLength Else message = "No PATH environment variable exists." End If MsgBox(message) End Sub
Namespace: Microsoft.VisualBasic
Module: Interaction
Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)
