程序代码：

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

/* first, here is the signal handler */
void catch_int(int sig_num) {
    /* re-set the signal handler again to 
     * catch_int, for next time 
     */
    signal(SIGINT, catch_int);
    printf("Dont't do that\n");
    fflush(stdout);
}

int main(int argc, char *argv[]) {
    /* set the INT (Ctrl-C) signal handler to 
     * 'catch_int
     */
    signal(SIGINT, catch_int);

    /* now, lets get into an infinite loop of doing
     * nothing
     */
    for( ; ; )
        pause();
}