http://kor.i2p/books/The%20C%20Programming%20Language%20by%20K&R/appb.html
Valid signals include SIGABRT abnormal termination, e.g., from abort SIGFPE arithmetic error, e.g., zero divide or overflow SIGILL illegal function image, e.g., illegal instruction SIGINT interactive attention, e.g., interrupt SIGSEGV illegal storage access, e.g., access outside memory limits SIGTERM termination request sent to this program signal returns the previous value of handler for the specific
signal, or SIG_ERR if an error occurs.