Mastering Linux Kernel Development

Signals

Signals are short messages delivered to a process or a process group. The kernel uses signals to notify processes about the occurrence of a system event; signals are also used for communication between processes. Linux categorizes signals into two groups, namely general-purpose POSIX (classic Unix signals) and real-time signals. Each group consists of 32 distinct signals, identified by a unique ID:

#define _NSIG 64#define _NSIG_BPW __BITS_PER_LONG#define _NSIG_WORDS (_NSIG / _NSIG_BPW)#define SIGHUP 1#define SIGINT 2#define SIGQUIT 3#define SIGILL 4#define SIGTRAP 5#define SIGABRT 6#define SIGIOT 6#define SIGBUS 7#define SIGFPE 8#define SIGKILL 9#define SIGUSR1 10#define SIGSEGV 11#define SIGUSR2 12#define SIGPIPE 13#define SIGALRM ...