BUG: WNetGetUniversalName Fails Under Windows 95

RESOLUTION

The functionality provided by WNetGetUniversalName can be implemented using the Win32 network enumeration functions WNetOpenEnum and WNetEnumResource. Here is an example of how to use these functions to implement similar functionality:

   #include <windows.h>
   #include <stdio.h>

   // Function Name:  GetUniversalName
   // 
   // Parameters:     szUniv  - Contains the UNC equivalent of szDrive
   //                           upon completion.
   // 
   //                 szDrive - Contains a drive-based path.
   // 
   // Return value:   TRUE if successful; otherwise, FALSE.
   // 
   // Comments:       This function assumes that szDrive contains a
   //                 valid drive-based path.
   // 
   //                 For simplicity, this code assumes szUniv points
   //                 to a buffer large enough to accommodate the UNC
   //                 equivalent of szDrive.

   BOOL GetUniversalName( char szUniv[], char szDrive[] )
   {

      // Get the local drive letter.
      char chLocal = toupper( szDrive[0] );

      // Cursory validation.
      if ( chLocal < 'A' || chLocal > 'Z' )
         return FALSE;

      if ( szDrive[1] != ':' || szDrive[2] != '\\' )
         return FALSE;

      HANDLE hEnum;
      DWORD dwResult = WNetOpenEnum( RESOURCE_CONNECTED, RESOURCETYPE_DISK,
                                     0, NULL, &hEnum );

      if ( dwResult != NO_ERROR )
         return FALSE;

      // Request all available entries.
      const int    c_cEntries   = 0xFFFFFFFF;
      // Start with a reasonable buffer size.
      DWORD        cbBuffer     = 50 * sizeof( NETRESOURCE );
      NETRESOURCE *pNetResource = (NETRESOURCE*) malloc( cbBuffer );

      BOOL fResult = FALSE;

      while ( TRUE )
      {
         DWORD dwSize   = cbBuffer,
               cEntries = c_cEntries;

         dwResult = WNetEnumResource( hEnum, &cEntries, pNetResource,
                                      &dwSize );

         if ( dwResult == ERROR_MORE_DATA )
         {
            // The buffer was too small, enlarge.
            cbBuffer = dwSize;
            pNetResource = (NETRESOURCE*) realloc(pNetResource, cbBuffer);
            continue;
         }

         if ( dwResult != NO_ERROR )
            goto done;

         // Search for the specified drive letter.
         for ( int i = 0; i < (int) cEntries; i++ )
            if ( pNetResource[i].lpLocalName &&
                 chLocal == toupper(pNetResource[i].lpLocalName[0]) )
            {
               // Match.
               fResult = TRUE;

               // Build a UNC name.
               strcpy( szUniv, pNetResource[i].lpRemoteName );
               strcat( szUniv, szDrive + 2 );
               _strupr( szUniv );
               goto done;
            }
      }

   done:

      // Clean up.
      WNetCloseEnum( hEnum );
      free( pNetResource );

      return fResult;

   }
				

An alternative workaround to using WNetOpenEnum and WNetEnumResource is to use WnetGetConnection, which, when provided the drive letter of a shared drive, returns the UNC name that is mapped to that drive.