It’s not quite as simple as setting a flag - if the signal is SIGBUS/SIGSEGV then returning from the handler normally will retry the faulting instruction. So, y

It’s not quite as simple as setting a flag - if the signal is SIGBUS/SIGSEGV then returning from the handler normally will retry the faulting instruction. So, you either have to map dummy memory into place so the fault doesn’t reoccur, or use sigsetjmp/siglongjmp to jump out to a previously configured exception handler (as Sublime Text did here. I think you’ve mixed up synchronous signals - SEGV, BUS, ABRT - with asynchronous signals like QUIT, INT, USR1. Asynchronous signals can be handled easily with a flag and a loop as you mentioned; synchronous signals are much trickier and much more complicated.