1、例子1
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
void test(int sig)
{
printf("\n test: I got signal %d\n",sig);
(void)signal(SIGINT,SIG_DFL);//将SIGINT信号处理方式改成默认,即退出
}
int main()
{
(void) signal(SIGINT,test);
while(1){
printf("hello main\n");
sleep(1);
}
return 0;
}
[root@localhost home]# ./sigtest
hello main
hello main
hello main
test: I got signal 2
hello main
hello main
第一次按下终止命令(ctrl+c)时,进程并没有被终止,面是输出test:I got signal 2,因为SIGINT的默认行为被signal函数改变了,当进程接受到信号SIGINT时,它就去调用函数test去处理,注意test函数把信号SIGINT的处理方式改变成默认的方式,所以当你再按一次ctrl+c时,进程就像之前那样被终止了。
2、例子2
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
void test(int sig)
{
printf("\n test: I got signal %d\n",sig);
//(void)signal(SIGINT,SIG_DEL);
}
int main()
{
struct sigaction act;
act.sa_handler=test;
sigemptyset(&act.sa_mask);
act.sa_flags=SA_RESETHAND;
sigaction(SIGINT,&act,0);
while(1)
{
printf("hello main\n");
sleep(1);
}
return 0;
}
结果:
[root@localhost home]# ./sigt1
hello main
hello main
hello main
test: I got signal 2
hello main
hello main
3、关于信号集函数,参考
https://blog.csdn.net/ljianhui/article/details/10130539