An overview of the message types, with a brief explanation
| I | Information message, report temporarily interrupted (except when run in background) |
| W | Warning message, program temporarily interrupted |
| E | Error message, program stops running untill error is corrected |
| S | Success or Skip message is reported on next screen |
| A | Abnormal program termination, program stops immediately |
| X | eXit Transaction terminated with short dump |
Note that if it is runtime progress indicating you want to use the MESSAGE statement for, there is a nice alternative to the "S", in function module SAPGUI_PROGRESS_INDICATOR,