在下面代碼中，在SIGINT信號處理過程中，屏蔽SIGQUIT信號的發生，信號SIGQUIT直到SIGINT的信號處理函數完畢后才能被處理

#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <string.h>#include <signal.h>void sig_handle(int signo){	int i = 5;	PRintf("catch signal %d/n", (int)signo);	while(i--)	{		printf("wait another signal/n");		sleep(1);	}}int main(int argc, char *argv[]){	struct sigaction newact, oldact;		newact.sa_handler = sig_handle;	sigemptyset(&newact.sa_mask);	sigaddset(&newact.sa_mask, SIGQUIT);	newact.sa_flags = 0;		sigaction(SIGINT, &newact, &oldact);		while(1)	{		printf("main process/n");		sleep(1);	}		return 0;}