三者都是会受调时间的影响1#include struct timeval boottime;int mib[2] = {CTL_KERN, KERN_BOOTTIME};size_t size = sizeof(boottime);if(sysctl(mib,2,&boottime,&size,NULL,0) != -1 && boottime.tv_sec != 0){ struct tm * tm; time_t time_sec ; time_sec = boottime.tv_sec; tm = localtime(&time_sec); CCLog("the time str is %s",CCString::createWithFormat("%d.%d.%d %d:%d:%d",(tm->tm_year + 1900),(tm->tm_mon + 1),tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec)->getCString());}2#import unsigned int nRunTime = [[NSProcessInfo processInfo] systemUptime];// 自最后一次开机至现在的运行时间 timeval now;gettimeofday(&now, NULL);unsigned int nStartTime = now.tv_sec - nRunTime;time_t time_sec;time_sec = nStartTime;struct tm * tm;tm = localtime(&time_sec);CCLog("the str is %s",CCString::createWithFormat("%d.%d.%d %d:%d:%d",(tm->tm_year + 1900),(tm->tm_mon + 1),tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec)->getCString());// 不推荐使用这种写法，因为官方对systemUptime的解释是The amount of time the system has been awake since the last time it was restarted.所以如果你是1:00重启(关机时间和开机时间都是1:00)的，则使用该方法获取的是自1:00到现在的时间；但如果你是1:00关机的,3:00开机的，则使用该方法获取的是自1:00到现在的时间，即自关机到现在的时间3#include -(NSTimeInterval) systemUptime{ struct timeval t; size_t len=sizeof(struct timeval); if(sysctlbyname("kern.boottime",&t,&len,0,0)!=0) return 0.0; return t.tv_sec+t.tv_usec/USEC_PER_SEC;}// 返回的是上一次开机到现在经过的秒数参考https://www.jianshu.com/p/82475b5a7e19
