sig_mask.c

LINUX C编程实战这本书附带光盘的原代码

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

/*自定义的错误处理函数*/
void my_err(const char * err_string, int line)
{
	fprintf(stderr, "line:%d  ", line);
	perror(err_string);
	exit(1);
}

/*SIGINT的处理函数*/
void hander_sigint(int signo)
{
	printf("recv SIGINT\n");
}

int main()
{
	sigset_t	newmask, oldmask, pendmask;	// 定义信号集

	/*安装信号处理函数*/
	if (signal(SIGINT, hander_sigint) == SIG_ERR) {
		my_err("signal", __LINE__);
	}
	
	/*睡眠10秒*/
	sleep(10); 

	/*初始化信号集newmask并将SIGINT添加进去*/
	sigemptyset(&newmask);
	sigaddset(&newmask, SIGINT);

	/*屏蔽信号SIGINT*/
	if (sigprocmask(SIG_BLOCK, &newmask, &oldmask) < 0) {
		my_err("sigprocmask", __LINE__);
	} else {
		printf("SIGINT blocked\n");
	}

	sleep(10);

	/*获取未决信号队列*/
	if (sigpending(&pendmask) < 0) {
		my_err("sigpending", __LINE__);
	}
	/*检查未决信号队列里面是否有SIGINT*/
	switch (sigismember(&pendmask, SIGINT)) {
		case 0:
			printf("SIGINT is not in pending queue\n");
			break;
		case 1:
			printf("SIGINT is in pending queue\n");
			break;
		case -1:
			my_err("sigismember", __LINE__);
			break;
		default:
			break;
	}
	
	/*解除对SIGINT的屏蔽*/
	if (sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0) {
		my_err("sigprocmask", __LINE__);
	} else {
		printf("SIGINT unblocked\n");
	}

	while(1)
		;

	return 0;
}