Universal Naming Convention (UNC)

Problem/Question/Abstract:

For file-based applications, how is the Universal Naming Convention obtained for path names?

Answer:

To get the UNC name of a drive-based path, use the Windows API call WNetGetUniversalName. This function takes a drive-based path (i.e., fully qualified file name) and returns its UNC equivalent.

Be forewarned, though: This call is not supported by Windows 95. Here's something that should work if you're in NT:

function GetUNCName(PathStr: string): string;
var
  bufSize: DWord;
  buf: TUniversalNameInfo;
  msg: string;
begin
  bufSize := SizeOf(TUniversalNameInfo);
  if (WNetGetUniversalName(PChar(PathStr), UNIVERSAL_NAME_INFO_LEVEL,
    buf, bufSize) > 0) then
    case GetLastError of
      ERROR_BAD_DEVICE: msg := 'ERROR_BAD_DEVICE';
      ERROR_CONNECTION_UNAVAIL: msg := 'ERROR_CONNECTION_UNAVAIL';
      ERROR_EXTENDED_ERROR: msg := 'ERROR_EXTENDED_ERROR';
      ERROR_MORE_DATA: msg := 'ERROR_MORE_DATA';
      ERROR_NOT_SUPPORTED: msg := 'ERROR_NOT_SUPPORTED';
      ERROR_NO_NET_OR_BAD_PATH: msg := 'ERROR_NO_NET_OR_BAD_PATH';
      ERROR_NO_NETWORK: msg := 'ERROR_NO_NETWORK';
      ERROR_NOT_CONNECTED: msg := 'ERROR_NOT_CONNECTED';
    end
  else
    msg := buf.lpUniversalName;

  Result := msg;
end;