.SH WARNINGS
Signals raised by any instruction in the instruction stream, including 
\f3\s-1SIGFPE\s+1\f1, \f3\s-1SIGILL\s+1\f1, \f3\s-1SIGEMT\s+1\f1, 
\f3\s-1SIGBUS\s+1\f1, and \f3\s-1SIGSEGV\s+1\f1, will cause infinite loops 
if their handler returns, or the action is set to 
.B \s-1SIG_IGN\s+1.
This is because the exception PC at the time of the signal points to the 
instruction that raised the exception or signal, and resuming the process 
will re-execute that same instruction.
.sp
The 
.SM POSIX
signal routines (\f2sigaction\f1(2), \f2sigpending\f1(2),
\f2sigprocmask\f1(2), \f2sigsuspend\f1(2), \f2sigsetjmp\f1(3)), 
and the 4.3\c
.SM BSD
signal routines (\f2sigvec\f1(3B), \f2signal\f1(3B), \f2sigblock\f1(3B),
\f2sigpause\f1(3B), \f2sigsetmask\f1(3B))
must 
.SM NEVER
be used with \f2signal\f1(2) or \f2sigset\f1(2). 
