If you are using third party software that posts a signal handler using a C library signal routine, such as signal() or sigaction(), unexpected results may occur. For example, if the third party software posts its handler before COBOL has been invoked, then when COBOL is invoked the third party's handler might be overridden by a run-time system or COBOL handler. If the third party subsequently raises a signal, then a 115 error may occur.
To overcome this, you can use the run-time tunable signal_regime. This tunable prevents handlers from being posted for the specified signal if a signal handler is posted before the first COBOL invocation.
If handlers are prevented from being posted for a signal, due to this tunable, the cobpostsighandler() routine returns NULL. Hence, the default run-time system handlers and any additional COBOL functionality achieved using the signal is not available. It also means that you should check the value returned from any cobpostsighandler() routine calls for NULL.
We recommend that you use the signal_regime tunable only with third party software. You should always use the cobpostsighandler() routine in your own code.