Linux 信号表 signals

Linux支持POSIX reliable signals和POSIX real-time signals。

信号处理

进程接受到信号之后会有一些默认的处理方式，如下为5种处理方式：

type	description
Term	Default action is to terminate the process.
Ign	Default action is to ignore the signal.
Core	Default action is to terminate the process and dump core (see core(5)).
Stop	Default action is to stop the process.
Cont	Default action is to continue the process if it is currently stopped.

若想改变signal的默认处理方式，可以看signal函数和sigaction函数。

发送信号

下面是一些系统调用或者库函数可以用于发送信号给某进程：

系统调用或库函数	描述
raise	Sends a signal to the calling thread.
kill	Sends a signal to a specified process, to all members of a specified process group, or to all processes on the system.
killpg	Sends a signal to all of the members of a specified process group.
pthread_kill	Sends a signal to a specified POSIX thread in the same process as the caller.
tgkill	Sends a signal to a specified thread within a specific process. (This is the system call used to implement pthread_kill(3).)
sigqueue	Sends a real-time signal with accompanying data to a specified process.

信号类型

Linux支持的信号很多，常用的有如下这些：

Signal	Value	Action	Comment
SIGHUP	1	Term	Hangup detected on controlling terminal or death of controlling process
SIGINT	2	Term	Interrupt from keyboard
SIGQUIT	3	Core	Quit from keyboard
SIGILL	4	Core	Illegal Instruction
SIGABRT	6	Core	Abort signal from abort(3)
SIGFPE	8	Core	Floating point exception
SIGKILL	9	Term	Kill signal
SIGSEGV	11	Core	Invalid memory reference
SIGPIPE	13	Term	Broken pipe: write to pipe with no readers
SIGALRM	14	Term	Timer signal from alarm(2)
SIGTERM	15	Term	Termination signal
SIGUSR1	30,10,16	Term	User-defined signal 1
SIGUSR2	31,12,17	Term	User-defined signal 2
SIGCHLD	20,17,18	Ign	Child stopped or terminated
SIGCONT	19,18,25	Cont	Continue if stopped
SIGSTOP	17,19,23	Stop	Stop process
SIGTSTP	18,20,24	Stop	Stop typed at terminal
SIGTTIN	21,21,26	Stop	Terminal input for background process
SIGTTOU	22,22,27	Stop	Terminal output for background process

其中value是可能的取值，因为在不同的系统上它的值不一样，最好使用宏进行操作比较安全，移植性也需要考虑。