Linux訊號處理

訊號是一種軟體中斷，程式收到訊號時，就會調用相應的處理函數（如果有註冊）。

void (*signal(int signum,void(* handler)(int)))(int); -- 設定訊號處理方式訊號處理函數原型void   foo(int arg); 系統定義的訊號有：/* Signals.  */#define SIGHUP1/* Hangup (POSIX).  */#define SIGINT2/* Interrupt (ANSI).  */#define SIGQUIT3/* Quit (POSIX).  */#define SIGILL4/* Illegal instruction (ANSI).  */#define SIGTRAP5/* Trace trap (POSIX).  */#define SIGABRT6/* Abort (ANSI).  */#define SIGIOT6/* IOT trap (4.2 BSD).  */#define SIGBUS7/* BUS error (4.2 BSD).  */#define SIGFPE8/* Floating-point exception (ANSI).  */#define SIGKILL9/* Kill, unblockable (POSIX).  */#define SIGUSR110/* User-defined signal 1 (POSIX).  */#define SIGSEGV11/* Segmentation violation (ANSI).  */#define SIGUSR212/* User-defined signal 2 (POSIX).  */#define SIGPIPE13/* Broken pipe (POSIX).  */#define SIGALRM14/* Alarm clock (POSIX).  */#define SIGTERM15/* Termination (ANSI).  */#define SIGSTKFLT16/* Stack fault.  */#define SIGCLDSIGCHLD/* Same as SIGCHLD (System V).  */#define SIGCHLD17/* Child status has changed (POSIX).  */#define SIGCONT18/* Continue (POSIX).  */#define SIGSTOP19/* Stop, unblockable (POSIX).  */#define SIGTSTP20/* Keyboard stop (POSIX).  */#define SIGTTIN21/* Background read from tty (POSIX).  */#define SIGTTOU22/* Background write to tty (POSIX).  */#define SIGURG23/* Urgent condition on socket (4.2 BSD).  */#define SIGXCPU24/* CPU limit exceeded (4.2 BSD).  */#define SIGXFSZ25/* File size limit exceeded (4.2 BSD).  */#define SIGVTALRM26/* Virtual alarm clock (4.2 BSD).  */#define SIGPROF27/* Profiling alarm clock (4.2 BSD).  */#define SIGWINCH28/* Window size change (4.3 BSD, Sun).  */#define SIGPOLLSIGIO/* Pollable event occurred (System V).  */#define SIGIO29/* I/O now possible (4.2 BSD).  */#define SIGPWR30/* Power failure restart (System V).  */#define SIGSYS31/* Bad system call.  */#define SIGUNUSED31 #define_NSIG65/* Biggest signal number + 1   (including real-time signals).  */ #define SIGRTMIN        (__libc_current_sigrtmin ())#define SIGRTMAX        (__libc_current_sigrtmax ())  向進程發送訊號（在終端）kill -s signal pid  -- signal的值是上面列表中的合法值kill -s 9 pid  -- 該命令會結束指定的進程 下面的例子顯示進程接收到的訊號

#include <unistd.h>#include <stdio.h>#include <signal.h>void handler(int arg){    printf("get signal %d\n", arg);    }int main(){    int i;    for (i=0; i<SIGRTMAX; i++)        signal(i, handler);    while(1)    {        pause();    }    return 0;}

 

可以用kill -s 9 pid結束它 kill也是一個可調用的APIint kill(pid_t pid,int sig); kill()可以用來送參數 sig指定的訊號給參數pid指定的進程。參數pid有幾種情況： pid>0 將訊號傳給進程識別碼為 pid的進程。 pid=0 將訊號傳給和目前進程相同進程組的所有進程 pid=-1 將訊號廣播傳送給系統內所有的進程pid<0 將訊號傳給進程組識別碼pid絕對值的所有進程