Environ Function

Returns the String value associated with an operating system environment variable.

Syntax

Environ(envstring | number)

Parameters

• envstring: Optional (if number provided). String expression containing the name of an environment variable.
• number: Optional (if envstring provided). Numeric expression corresponding to the numeric order of an environment string in the environment-string table. The number argument can be any numeric expression, but is rounded to a whole number before it is evaluated.

Return Value

Returns a String containing the value assigned to envstring or the environment variable at position number. Returns a zero-length string ("") if envstring is not found or if there is no environment string at position number.

Remarks

The Environ function retrieves values from the operating system's environment variables. Environment variables are system-level or user-level settings that provide information about the operating system environment.

Important Characteristics:

• Reads environment variables from the operating system
• Can access by name (string) or position (number)
• Case-insensitive on Windows
• Returns empty string if variable not found
• Position-based access starts at 1 (not 0)
• Number of environment variables varies by system
• Environment changes during execution are not reflected
• Snapshot taken at application start
• Cannot modify environment variables (read-only)
• Different users may have different environment variables

Common Environment Variables

Windows: - PATH - Executable search path - TEMP or TMP - Temporary files directory - USERNAME - Current user name - USERPROFILE - User's profile directory - COMPUTERNAME - Computer name - SYSTEMROOT - Windows system directory - PROGRAMFILES - Program Files directory - HOMEDRIVE - User's home drive (e.g., C:) - HOMEPATH - User's home directory path - APPDATA - Application data directory - WINDIR - Windows directory - PROCESSOR_ARCHITECTURE - CPU architecture - NUMBER_OF_PROCESSORS - Number of CPU cores - OS - Operating system name

Examples

Basic Usage

' Get environment variable by name
Dim userName As String
userName = Environ("USERNAME")
MsgBox "Current user: " & userName

' Get temp directory
Dim tempDir As String
tempDir = Environ("TEMP")

' Get by position
Dim firstEnvVar As String
firstEnvVar = Environ(1)

Check if Variable Exists

Function EnvironVarExists(varName As String) As Boolean
EnvironVarExists = (Len(Environ(varName)) > 0)
End Function

' Usage
If EnvironVarExists("JAVA_HOME") Then
MsgBox "Java is configured"
Else
MsgBox "Java not found"
End If

Build File Paths

Function GetTempFilePath(fileName As String) As String
Dim tempDir As String
tempDir = Environ("TEMP")

If Right(tempDir, 1) <> "\" Then
tempDir = tempDir & "\"
End If

GetTempFilePath = tempDir & fileName
End Function

Common Patterns

Get User Directories

Function GetUserProfile() As String
GetUserProfile = Environ("USERPROFILE")
End Function

Function GetAppDataPath() As String
GetAppDataPath = Environ("APPDATA")
End Function

Function GetDesktopPath() As String
GetDesktopPath = Environ("USERPROFILE") & "\Desktop"
End Function

Function GetMyDocuments() As String
GetMyDocuments = Environ("USERPROFILE") & "\Documents"
End Function

System Information

Function GetComputerName() As String
GetComputerName = Environ("COMPUTERNAME")
End Function

Function GetProcessorCount() As Integer
Dim procCount As String
procCount = Environ("NUMBER_OF_PROCESSORS")

If IsNumeric(procCount) Then
GetProcessorCount = CInt(procCount)
Else
GetProcessorCount = 1
End If
End Function

Function GetSystemArchitecture() As String
GetSystemArchitecture = Environ("PROCESSOR_ARCHITECTURE")
End Function

List All Environment Variables

Sub ListAllEnvironmentVariables()
Dim i As Integer
Dim envVar As String

i = 1
Do
envVar = Environ(i)
If envVar = "" Then Exit Do

Debug.Print i & ": " & envVar
i = i + 1
Loop
End Sub

Parse Environment Variable

Function GetEnvironVarName(envString As String) As String
Dim equalPos As Integer
equalPos = InStr(envString, "=")

If equalPos > 0 Then
GetEnvironVarName = Left(envString, equalPos - 1)
Else
GetEnvironVarName = ""
End If
End Function

Function GetEnvironVarValue(envString As String) As String
Dim equalPos As Integer
equalPos = InStr(envString, "=")

If equalPos > 0 Then
GetEnvironVarValue = Mid(envString, equalPos + 1)
Else
GetEnvironVarValue = ""
End If
End Function

Safe Path Construction

Function BuildSafePath(envVar As String, subPath As String) As String
Dim basePath As String
basePath = Environ(envVar)

If basePath = "" Then
BuildSafePath = ""
Exit Function
End If

' Ensure path ends with backslash
If Right(basePath, 1) <> "\" Then
basePath = basePath & "\"
End If

' Remove leading backslash from subPath if present
If Left(subPath, 1) = "\" Then
subPath = Mid(subPath, 2)
End If

BuildSafePath = basePath & subPath
End Function

Configuration File Paths

Function GetConfigFilePath(appName As String, fileName As String) As String
Dim appDataPath As String
Dim configDir As String

appDataPath = Environ("APPDATA")
configDir = appDataPath & "\" & appName

' Create directory if it doesn't exist
If Dir(configDir, vbDirectory) = "" Then
MkDir configDir
End If

GetConfigFilePath = configDir & "\" & fileName
End Function

Search PATH Variable

Function FindInPath(executable As String) As String
Dim pathVar As String
Dim paths() As String
Dim i As Integer
Dim testPath As String

pathVar = Environ("PATH")
paths = Split(pathVar, ";")

For i = LBound(paths) To UBound(paths)
testPath = paths(i) & "\" & executable
If Dir(testPath) <> "" Then
FindInPath = testPath
Exit Function
End If
Next i

FindInPath = ""
End Function

Check Operating System

Function IsWindows() As Boolean
Dim osVar As String
osVar = UCase(Environ("OS"))
IsWindows = (InStr(osVar, "WINDOWS") > 0)
End Function

Function GetWindowsDirectory() As String
GetWindowsDirectory = Environ("WINDIR")
End Function

Function GetSystemRoot() As String
GetSystemRoot = Environ("SYSTEMROOT")
End Function

Program Files Paths

Function GetProgramFilesPath() As String
GetProgramFilesPath = Environ("PROGRAMFILES")
End Function

Function GetProgramFilesX86Path() As String
GetProgramFilesX86Path = Environ("PROGRAMFILES(X86)")
End Function

Function FindProgramPath(programName As String) As String
Dim progFiles As String
Dim testPath As String

' Check Program Files
progFiles = Environ("PROGRAMFILES")
testPath = progFiles & "\" & programName
If Dir(testPath, vbDirectory) <> "" Then
FindProgramPath = testPath
Exit Function
End If

' Check Program Files (x86)
progFiles = Environ("PROGRAMFILES(X86)")
If progFiles <> "" Then
testPath = progFiles & "\" & programName
If Dir(testPath, vbDirectory) <> "" Then
FindProgramPath = testPath
Exit Function
End If
End If

FindProgramPath = ""
End Function

Advanced Usage

Environment Variable Dictionary

Function GetEnvironmentDictionary() As Collection
Dim dict As New Collection
Dim i As Integer
Dim envVar As String
Dim varName As String
Dim varValue As String
Dim equalPos As Integer

i = 1
Do
envVar = Environ(i)
If envVar = "" Then Exit Do

equalPos = InStr(envVar, "=")
If equalPos > 0 Then
varName = Left(envVar, equalPos - 1)
varValue = Mid(envVar, equalPos + 1)

On Error Resume Next
dict.Add varValue, UCase(varName)
On Error GoTo 0
End If

i = i + 1
Loop

Set GetEnvironmentDictionary = dict
End Function

Expand Environment Variables in String

Function ExpandEnvironmentString(inputString As String) As String
Dim result As String
Dim startPos As Integer
Dim endPos As Integer
Dim varName As String
Dim varValue As String

result = inputString

' Find %VAR% patterns
Do
startPos = InStr(result, "%")
If startPos = 0 Then Exit Do

endPos = InStr(startPos + 1, result, "%")
If endPos = 0 Then Exit Do

varName = Mid(result, startPos + 1, endPos - startPos - 1)
varValue = Environ(varName)

result = Left(result, startPos - 1) & varValue & Mid(result, endPos + 1)
Loop

ExpandEnvironmentString = result
End Function

' Usage
expandedPath = ExpandEnvironmentString("%TEMP%\myfile.txt")

Create Application Log File

Function CreateLogFile(appName As String) As String
Dim logDir As String
Dim logFile As String
Dim dateStamp As String

logDir = Environ("TEMP") & "\Logs"

' Create logs directory
If Dir(logDir, vbDirectory) = "" Then
MkDir logDir
End If

dateStamp = Format(Date, "yyyy-mm-dd")
logFile = logDir & "\" & appName & "_" & dateStamp & ".log"

CreateLogFile = logFile
End Function

Check Development Environment

Function IsDevelopmentEnvironment() As Boolean
' Check for common development environment variables
IsDevelopmentEnvironment = (Len(Environ("VSCODE_PID")) > 0) Or _
(Len(Environ("TERM_PROGRAM")) > 0) Or _
(Len(Environ("VSAPPIDDIR")) > 0)
End Function

Function GetJavaHome() As String
GetJavaHome = Environ("JAVA_HOME")
End Function

Function GetPythonPath() As String
GetPythonPath = Environ("PYTHONPATH")
End Function

Build Connection String

Function BuildConnectionString() As String
Dim server As String
Dim database As String

server = Environ("DB_SERVER")
database = Environ("DB_NAME")

If server = "" Then server = "localhost"
If database = "" Then database = "default"

BuildConnectionString = "Server=" & server & ";Database=" & database
End Function

Export Environment to File

Sub ExportEnvironmentToFile(filePath As String)
Dim fileNum As Integer
Dim i As Integer
Dim envVar As String

fileNum = FreeFile
Open filePath For Output As #fileNum

Print #fileNum, "Environment Variables"
Print #fileNum, "Generated: " & Now
Print #fileNum, String(80, "-")

i = 1
Do
envVar = Environ(i)
If envVar = "" Then Exit Do

Print #fileNum, envVar
i = i + 1
Loop

Close #fileNum
End Sub

Portable Path Builder

Function GetPortableAppPath(relativePath As String) As String
Dim basePath As String

' Try to get from environment first
basePath = Environ("APP_BASE_PATH")

' Fall back to current directory
If basePath = "" Then
basePath = App.Path
End If

If Right(basePath, 1) <> "\" Then
basePath = basePath & "\"
End If

GetPortableAppPath = basePath & relativePath
End Function

Error Handling

Function SafeEnviron(varName As String, Optional defaultValue As String = "") As String
On Error Resume Next
SafeEnviron = Environ(varName)

If Err.Number <> 0 Or SafeEnviron = "" Then
SafeEnviron = defaultValue
End If
End Function

Function GetEnvironWithFallback(preferredVar As String, fallbackVar As String) As String
GetEnvironWithFallback = Environ(preferredVar)

If GetEnvironWithFallback = "" Then
GetEnvironWithFallback = Environ(fallbackVar)
End If
End Function

Common Errors

• Error 5 (Invalid procedure call): Invalid number argument (< 1)
• No error for missing variables (returns empty string)

Performance Considerations

• Environ is relatively fast (direct OS call)
• Environment snapshot taken at application start
• Cache frequently used values to avoid repeated calls
• Position-based enumeration stops at first empty string
• String comparison is case-insensitive on Windows

Best Practices

Always Check for Empty String

' Good - Check before using
tempDir = Environ("TEMP")
If tempDir = "" Then
tempDir = "C:\Temp"  ' Fallback
End If

' Avoid - Assuming variable exists
tempDir = Environ("TEMP")  ' May be empty!

Use Constants for Variable Names

' Good - Constants for maintainability
Const ENV_TEMP = "TEMP"
Const ENV_USERNAME = "USERNAME"

tempDir = Environ(ENV_TEMP)
userName = Environ(ENV_USERNAME)

Provide Defaults

Function GetTempDir() As String
GetTempDir = Environ("TEMP")
If GetTempDir = "" Then GetTempDir = Environ("TMP")
If GetTempDir = "" Then GetTempDir = "C:\Temp"
End Function

Case Insensitive on Windows

' All equivalent on Windows
userName = Environ("USERNAME")
userName = Environ("username")
userName = Environ("UserName")

Comparison with Other Methods

Environ vs Registry

' Environ - Quick, read-only access to environment
tempDir = Environ("TEMP")

' Registry - More control, can read/write, more complex
' (Requires Windows API or Registry object)

Environ vs Command Line

' Environ - Environment variables
userName = Environ("USERNAME")

' Command - Command line arguments
args = Command()

Limitations

• Read-only access (cannot modify environment variables)
• Snapshot at application start (changes not reflected)
• Position-based enumeration order not guaranteed
• Cannot create or delete environment variables
• Limited to process environment (not system-wide)
• No wildcard or pattern matching
• Case-sensitive on Unix/Linux (VB6 primarily Windows)

Related Functions

• Command: Returns command-line arguments
• CurDir: Returns current directory
• ChDir: Changes current directory
• App.Path: Returns application path
• Shell: Executes external programs (can set environment)
• GetSetting: Reads application settings from registry
• SaveSetting: Writes application settings to registry