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代码： 全选

#include<stdio.h>
#include<signal.h>
#include<assert.h>

int main(int argc,char *argv[])
{
	for(;;)system("date;sleep 1");
}

代码： 全选

$ ./a.out
$ pstree -p -g 462
bash(462)───a.out(1995)───sh(2001)───sleep(2003)
$ cat /proc/1995/status | grep Sig
SigQ:   0/15000
SigPnd: 0000000000000000
SigBlk: 0000000000010000
SigIgn: 0000000000000086
SigCgt: 0000000000000000
$ cat /proc/2001/status | grep Sig
SigQ:   0/15000
SigPnd: 0000000000000000
SigBlk: 0000000000010000
SigIgn: 0000000000000084
SigCgt: 0000000000010002
$ cat /proc/2003/status | grep Sig
SigQ:   0/15000
SigPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000080
SigCgt: 0000000000000000

代码： 全选

SYSTEM(3)                  Linux Programmer's Manual                 SYSTEM(3)

NAME
       system - execute a shell command

SYNOPSIS
       #include <stdlib.h>

       int system(const char *command);

DESCRIPTION
       The  system()  library  function uses fork(2) to create a child process
       that executes the shell command specified in command using execl(3)  as
       follows:

           execl("/bin/sh", "sh", "-c", command, (char *) 0);

       system() returns after the command has been completed.

       During  execution  of  the command, SIGCHLD will be blocked, and SIGINT
       and SIGQUIT will be ignored, in the process that calls system()  (these
       signals  will  be  handled according to their defaults inside the child
       process that executes command).

       If command is NULL, then system() returns a status indicating whether a
       shell is available on the system