前言部分
大家可以關注我的公眾號，公眾號里的排版更好，閱讀更舒適。
正文部分
關於系統的消息類型：
寫MESSAGE一定要加上TYPE
那么消息類型有幾種呢
message types： "A", "E", "I", "S", "W", or "X"
One of the possible message types "A", "E", "I", "S", "W", or "X" must be specified
For messages displayed in a dialog box by default, the short text is still displayed as a dialog box.
Messages with the type "E" or "W" (except those for PBO and LOAD-OF-PROGRAM) are displayed as a dialog window if dtype contains "A" or "I".
Messages with the type "S" are always displayed in the status bar, regardless of the dtype.
The latter also applies to messages of the type "I" for PBO and LOAD-OF-PROGRAM.
Messages of the type "X" always cause a runtime error.
按照上面的順序分析一下
A：Abend 異常終止 終止當前操作
E：Error 錯誤 系統等待 新輸入數據
I： Infor 信息 處理回車之后 系統繼續處理
S：Success成功 消息出現 在下一屏上
W：Warning警告 可以更改 輸入數據或 通過按回車繼續
X：EXIT 退出 退出操作 或返回上一層操作 通常是運行時錯誤
matinal