Thank you for your response.

It could also be that you should not exit() within the signal handler, but instead should set a flag which causes the main loop of the child process to end as-soon as-possible.

When this is done, then, no matter what the process was doing at the unpredictable instant in which the termination-signal arrived, you know that it will end at a predictable point and in a predictable state

Yes, that's often good idea to just set flag in signal handler.

However, I was hoping that Perl is kinda high-level language, so there can be nothing unpredictible in termination in random point of program (with Safe-signals).

Another problem, that my child processes have several possible places where they can spend significant amount of time. Inserting check for flag in all of those places is inconvenient.