35 lines
745 B
C
35 lines
745 B
C
#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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//!!! 不加volatile关键字，loop变量的值不会被修改，导致死循环!!!
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static volatile int loop = 1;
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static void alrm_handler(int sig)
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{
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loop = 0;
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}
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/***********************************************************************
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* @brief 用sig实现计时
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* @param argc
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* @param argv
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* @return int
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***********************************************************************/
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int main(int argc, char **argv)
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{
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long long count = 0;
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//!!!
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signal(SIGALRM, alrm_handler);
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alarm(5);
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//!!! signal注册时钟信号的行为需要在alarm之前
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while (loop)
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count++;
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printf("%lld \n", count);
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exit(0);
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} |