Linux中不同數值的signal有不同的含義，所包含的信息如下
#define SIG_ERR ((__sighandler_t) -1) /* Error return. */
#define SIG_DFL ((__sighandler_t) 0) /* Default action. */
#define SIG_IGN ((__sighandler_t) 1) /* Ignore signal. */
#ifdef __USE_UNIX98
# define SIG_HOLD ((__sighandler_t) 2) /* Add signal to hold mask. */
#endif
/* Signals. */
#define SIGHUP 1 /* Hangup (POSIX). */
#define SIGINT 2 /* Interrupt (ANSI). */
#define SIGQUIT 3 /* Quit (POSIX). */
#define SIGILL 4 /* Illegal instruction (ANSI). */
#define SIGTRAP 5 /* Trace trap (POSIX). */
#define SIGABRT 6 /* Abort (ANSI). */
#define SIGIOT 6 /* IOT trap (4.2 BSD). */
#define SIGBUS 7 /* BUS error (4.2 BSD). */
#define SIGFPE 8 /* Floating-point exception (ANSI). */
#define SIGKILL 9 /* Kill, unblockable (POSIX). */
#define SIGUSR1 10 /* User-defined signal 1 (POSIX). */
#define SIGSEGV 11 /* Segmentation violation (ANSI). */
#define SIGUSR2 12 /* User-defined signal 2 (POSIX). */
#define SIGPIPE 13 /* Broken pipe (POSIX). */
#define SIGALRM 14 /* Alarm clock (POSIX). */
#define SIGTERM 15 /* Termination (ANSI). */
#define SIGSTKFLT 16 /* Stack fault. */
#define SIGCLD SIGCHLD /* Same as SIGCHLD (System V). */
#define SIGCHLD 17 /* Child status has changed (POSIX). */
#define SIGCONT 18 /* Continue (POSIX). */
#define SIGSTOP 19 /* Stop, unblockable (POSIX). */
#define SIGTSTP 20 /* Keyboard stop (POSIX). */
#define SIGTTIN 21 /* Background read from tty (POSIX). */
#define SIGTTOU 22 /* Background write to tty (POSIX). */
#define SIGURG 23 /* Urgent condition on socket (4.2 BSD). */
#define SIGXCPU 24 /* CPU limit exceeded (4.2 BSD). */
#define SIGXFSZ 25 /* File size limit exceeded (4.2 BSD). */
#define SIGVTALRM 26 /* Virtual alarm clock (4.2 BSD). */
#define SIGPROF 27 /* Profiling alarm clock (4.2 BSD). */
#define SIGWINCH 28 /* Window size change (4.3 BSD, Sun). */
#define SIGPOLL SIGIO /* Pollable event occurred (System V). */
#define SIGIO 29 /* I/O now possible (4.2 BSD). */
#define SIGPWR 30 /* Power failure restart (System V). */
#define SIGSYS 31 /* Bad system call. */
#define SIGUNUSED 31
#define _NSIG 65 /* Biggest signal number + 1
(including real-time signals). */
#define SIGRTMIN (__libc_current_sigrtmin ())
#define SIGRTMAX (__libc_current_sigrtmax ())
/* These are the hard limits of the kernel. These values should not be
used directly at user level. */
#define __SIGRTMIN 32
#define __SIGRTMAX (_NSIG - 1)
另外可以參考博客
https://blog.csdn.net/wesleyluo/article/details/5279482
