#include <stdio.h>
#include <signal.h>
#include <setjmp.h>
#include <unistd.h>
#include <sys/time.h>

?

sigjmp_buf jmp_env;

static void connect_alarm(int)
{
??? siglongjmp(jmp_env, 1);
}

int main()
{
??? // 當超時時間sec_timeout大于等于運行時間run_time時會跳過printf("running.../n");
??? int sec_timeout = 3;
??? int run_time = 2;

??? printf("timeout = %d, run time = %d/n", sec_timeout, run_time);
??? if (sec_timeout)
??? {
??????? // 超過用alarm函數設置的時間時產生此信號，調用connect_alarm函數
??????? signal(SIGALRM, connect_alarm);
??????? alarm(sec_timeout);
??????? printf("set timeout/n");
??????? if (sigsetjmp(jmp_env, 1))
??????? {
??????????? printf("timeout/n");
??????????? goto out;
??????? }
??? }

??? sleep(run_time);
??? printf("running.../n");

out:
??? if (sec_timeout)
??? {
??????? // 取消先前設置的鬧鐘
??????? alarm(0);
??????? printf("cancel timeout/n");
??? }

??? return 0;
}