Microsoft KB Archive/82002

= Using ENVIRON$ to Detect Whether Running Under Windows =

Article ID: 82002

Article Last Modified on 8/16/2005

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APPLIES TO


 * Microsoft QuickBasic 4.0
 * Microsoft QuickBASIC 4.0b
 * Microsoft QuickBasic 4.5 for MS-DOS
 * Microsoft BASIC Professional Development System 7.0
 * Microsoft BASIC Professional Development System 7.1
 * Microsoft Cinemania 97 Standard Edition
 * Microsoft Windows 3.0 Standard Edition
 * Microsoft Windows 3.1 Standard Edition
 * Microsoft GW-BASIC Interpreter 3.20
 * Microsoft GW-BASIC Interpreter 3.23
 * Microsoft GW-BASIC Interpreter 3.22
 * Microsoft GW-BASIC Interpreter 3.23

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This article was previously published under Q82002



SUMMARY
A Microsoft Basic program can detect whether it is running under Microsoft Windows by checking for the existence of the environment variable &quot;windir&quot; with the function ENVIRON$.

This information applies to Microsoft QuickBasic versions 4.0, 4.0b, and 4.5 for MS-DOS; Microsoft Basic Professional Development System (PDS) versions 7.0 and 7.1 for MS-DOS; Microsoft Basic Compiler versions 6.0 and 6.0b for MS-DOS; Microsoft GW-Basic Interpreter versions 3.2, 3.22, and 3.23 for MS-DOS; and Microsoft Windows versions 3.0 and 3.1.



MORE INFORMATION
When Windows runs a program, it supplies the environment variable named &quot;windir&quot; that specifies the full path of the directory where Windows is installed. Note that this environment variable name is spelled with lowercase letters.

If a Basic program is running under Microsoft Windows, the expression ENVIRON$(&quot;windir&quot;) returns a non-null string, otherwise it returns a null string.

Example Code
IF ENVIRON$(&quot;windir&quot;) <> &quot;&quot; THEN PRINT &quot;running under Windows&quot; ELSE PRINT &quot;not running under Windows&quot; END IF

Additional query words: QuickBas BasicCom 3.00 3.10 4.00 4.00b 4.50 6.00 6.00b 7.00 7.10

Keywords: KB82002

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