D3 uses only UNIX System V.3 signals, which are common to more recent UNIX versions. Those systems that are not UNIX System V.3 signals are left to their default signal handler (such as, SIG_IGN) as set by the system.
Numerical values may vary between UNIX implementations. It is extremely important to use the correct include statement when writing in C and when writing in FlashBASIC programs using signals, for example, include dm,bp,unix.h, signal.h.