## INFO: Which Windows NT (Server or Workstation) Is Running?

Q124305

The information in this article applies to:

- Microsoft Win32 Application Programming Interface (API), used with:
  - the operating system: Microsoft Windows NT, versions 3.51, 4.0

## SUMMARY

You can determine which variant of Windows NT (Windows NT Server or Windows NT Workstation) is running by using the technique described in this article. Then you can use this information to execute code based on which variant is running.

## MORE INFORMATION

To find out which product is currently running, you need to determine the value of the following registry entry:

    HKEY_LOCAL_MACHINE\SYSTEM\
    CurrentControlSet\
    Control\
    ProductOptions

Use the following table to determine which product is running:

    ProductType   Product
    ----------------------------------------------------
    WINNT         Windows NT Workstation is running
    SERVERNT      Windows NT Server is running
    LANMANNT      Windows NT Advanced Server is running (Server as Domain
                  controller)

The sample code creates a WhichNTProduct() function to indicate whether Windows NT Server or Windows NT Workstation in currently running. The following table gives the meaning for each return value:

    Return Value       Meaning
    ---------------------------------------------------------
    RTN_SERVER         Windows NT Server is running
    RTN_WORKSTATION    Windows NT Workstation is running
    RTN_NTAS           Windows NT Advanced Server is running
    RTN_UNKNOWN        Unknown product type was encountered
    RTN_ERROR          Error occurred

To get extended error information, call GetLastError(). Some error checking is omitted, for brevity.

### Sample Code

       #define RTN_UNKNOWN 0
       #define RTN_SERVER 1
       #define RTN_WORKSTATION 2
       #define RTN_NTAS 3
       #define RTN_ERROR 13

       unsigned int WhichNTProduct(void)

       DWORD
       WhichNTProduct(
           void
           )
       {
           #define MY_BUFSIZE 32 // arbitrary. Use dynamic allocation
           HKEY hKey;
           TCHAR szProductType[MY_BUFSIZE];
           DWORD dwBufLen=MY_BUFSIZE;
           LONG lRet;

           if(RegOpenKeyEx(HKEY_LOCAL_MACHINE,

       TEXT("SYSTEM\\CurrentControlSet\\Control\\ProductOptions"),
                           0,
                           KEY_QUERY_VALUE,
                           &hKey) != ERROR_SUCCESS) return RTN_ERROR;

           lRet = RegQueryValueEx(hKey,
                           TEXT("ProductType"),
                           NULL,
                           NULL,
                           (LPBYTE)szProductType,
                           &dwBufLen);

           RegCloseKey(hKey);

           if(lRet != ERROR_SUCCESS) return RTN_ERROR;

           // check product options, in order of likelihood
           if (lstrcmpi(TEXT("WINNT"), szProductType) == 0)
              return RTN_WORKSTATION;
           if(lstrcmpi(TEXT("SERVERNT"), szProductType) == 0)
              return RTN_SERVER;
           if(lstrcmpi(TEXT("LANMANNT"), szProductType) == 0) return RTN_NTAS;

           // else return Unknown
           return RTN_UNKNOWN;
       }

Additional query words:

Keywords : _IK kbnokeyword kbKernBase kbRegistry kbDSupport kbGrpDSKernBase
Issue type : kbinfo
Technology : kbAudDeveloper kbWin32sSearch kbWin32API

Last Reviewed: October 22, 2000 © 2001 Microsoft Corporation. All rights reserved. Terms of Use.