The following signals can be handled by Factor programs:

•	SIGWINCH
•	SIGCONT
•	SIGURG
•	SIGIO
•	SIGPROF
•	SIGALRM
•	SIGVTALRM
•	SIGINFO (if available on the host platform)
•	SIGUSR1

Synchronous signals such as SIGILL, SIGFPE, SIGBUS, and SIGSEGV are handled by the Factor implementation and reported as exceptions when appropriate. SIGUSR2 is used by Factor internally. SIGALRM is used by the sampling profiler while profiling is active. SIGINT pauses the VM and enters the low-level debugger (like the die word); it cannot yet be handled reliably by Factor code. Factor does not install a handler for SIGQUIT.