-- Copyright (C) 1980, 1982, 1985  by Xerox Corporation. All rights reserved. 
-- TTYPortHeadNIL.mesa, HGM, 18-Nov-85 19:19:04

DIRECTORY
  TTYPortFace;

TTYPortHeadNIL: PROGRAM
  EXPORTS TTYPortFace =
  BEGIN

  GetCommand: PUBLIC PROC [CARDINAL]
    RETURNS [data: CHARACTER, stat: TTYPortFace.TransferStatus] =
    BEGIN
    RETURN[NULL, notReady];
    END;

  GetLineCount: PUBLIC PROC RETURNS [CARDINAL] = {RETURN[1]};

  GetStatus: PUBLIC PROC [CARDINAL] RETURNS [TTYPortFace.DeviceStatus] =
    BEGIN
    RETURN[[
      readyToPut: TRUE,
      readyToGet: FALSE,
      dataTerminalReady: TRUE,
      requestToSend: TRUE]];
    END;

  PutCommand: PUBLIC PROC [lineNumber: CARDINAL, data: CHARACTER]
    RETURNS [TTYPortFace.TransferStatus] =
    BEGIN
    RETURN[success];
    END;

  SendBreak: PUBLIC PROC [lineNumber: CARDINAL] =
    BEGIN
    END;

  SetParameter: PUBLIC PROC [lineNumber: CARDINAL, parameter: TTYPortFace.Parameter] =
    BEGIN
    END;

  On: PUBLIC PROC [lineNumber: CARDINAL, mask: UNSPECIFIED] =
    BEGIN
    END;

  Off: PUBLIC PROC [CARDINAL] =
    BEGIN
    END;

  END....