Marcin is right. We must be very cautious, what a signal handler does.The list in the sigaction manpage is nice finding. Thank you! In screen it prooved to be fatal, if a signal handler does malloc()/free(). That easily leads to invalid pointers in the rest of the code.
take care, Jürgen- Marcin Cieślak <invalid.nore...@gnu.org> schrieb am Sa., 28. Dez. 2019 20:35: > Follow-up Comment #12, bug #25089 (project screen): > > The reason for this is that in the C language only some very narrow set of > library functions can be invoked from the signal handler > > FreeBSD sigaction(2) manpage lists them and adds: > > > https://www.freebsd.org/cgi/man.cgi?query=sigaction&apropos=0&sektion=2&manpath=FreeBSD+12.1-RELEASE+and+Ports&arch=default&format=html > > > All functions not in the above lists are considered to be unsafe with > > respect to signals. That is to say, the behaviour of such functions is > > undefined when they are called from a signal handler that interrupted an > > unsafe function. In general though, signal handlers should do little > > more than set a flag; most other actions are not safe. > > Therefore it was the best practice in the signal handlers only to set the > variable and deal with the actual handling later. > > _______________________________________________________ > > Reply to this item at: > > <https://savannah.gnu.org/bugs/?25089> > > _______________________________________________ > Message sent via Savannah > https://savannah.gnu.org/ > > >
