| 0 | The run-time system uses the signal sig if it needs to. By default, the run-time system sets up signal handlers for all signals whose operating system default action would cause termination. The run-time system can thus catch these signals and tidy up (for example, close any open files to prevent file corruption) before exiting. |
| 1 | The run-time system uses the signal sig if, and only if, a handler was not already posted for this signal. This is useful if the third-party software is invoked before your COBOL system and sets up a handler for signal sig. If this tunable is not set for this signal, the run-time system overwrites the third-party software's handler with its own; this leads to unpredictable behavior, such as run-time system error 115 ("Unexpected signal") being produced. If a handler was posted, the run-time system will not post any handlers for this signal and so any run-time system functionality which relies on this signal will not work. |
| 2 | The run-time system never uses the signal sig. This is only of use if the third-party software is invoked after the run-time system and sets up a handler for signal sig. Use of this setting is strongly discouraged for any signal whose operating system default action is to cause termination; if this signal is received between the run-time system being invoked and the third-party software setting up its handler, the default action of the operating system occurs, and the process exits without the run-time system being able to tidy up. This could lead to problems such as file corruption. Any run-time system functionality which relies on this signal will not work. |
Comments:
If you use the alternative syntax (set signal_regime=1), the signal regime for all signals is set to 1.