一、struct timespec 定義:
typedef long time_t;
#ifndef _TIMESPEC
#define _TIMESPEC
struct timespec {
time_t tv_sec; // seconds
long tv_nsec; // and nanoseconds
};
#endif
struct timespec有兩個成員,一個是秒,一個是納秒, 所以最高精確度是納秒。
一般由函數int clock_gettime(clockid_t, struct timespec *)獲取特定時鐘的時間,常用如下4種時鐘:
CLOCK_REALTIME 系統當前時間,從1970年1.1日算起
CLOCK_MONOTONIC 系統的啓動時間,不能被設置
CLOCK_PROCESS_CPUTIME_ID 本進程運行時間
CLOCK_THREAD_CPUTIME_ID 本線程運行時間
struct tm *localtime(const time_t *clock); //線程不安全
struct tm* localtime_r( const time_t* timer, struct tm* result );//線程安全
size_t strftime (char* ptr, size_t maxsize, const char* format,const struct tm* timeptr );
二、struct timeval 定義:
struct timeval {
time_t tv_sec; // seconds
long tv_usec; // microseconds
};
struct timezone{
int tz_minuteswest; //miniutes west of Greenwich
int tz_dsttime; //type of DST correction
};
struct timeval有兩個成員,一個是秒,一個是微秒, 所以最高精確度是微秒。
一般由函數int gettimeofday(struct timeval *tv, struct timezone *tz)獲取系統的時間
#include<stdio.h>
#include<time.h>
#include<sys/time.h>
void nowtime_ns()
{
printf("---------------------------struct timespec---------------------------------------\n");
printf("[time(NULL)] : %ld\n", time(NULL));
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
printf("clock_gettime : tv_sec=%ld, tv_nsec=%ld\n", ts.tv_sec, ts.tv_nsec);
struct tm t;
char date_time[64];
strftime(date_time, sizeof(date_time), "%Y-%m-%d %H:%M:%S", localtime_r(&ts.tv_sec, &t));
printf("clock_gettime : date_time=%s, tv_nsec=%ld\n", date_time, ts.tv_nsec);
}
void nowtime_us()
{
printf("---------------------------struct timeval----------------------------------------\n");
printf("[time(NULL)] : %ld\n", time(NULL));
struct timeval us;
gettimeofday(&us,NULL);
printf("gettimeofday: tv_sec=%ld, tv_usec=%ld\n", us.tv_sec, us.tv_usec);
struct tm t;
char date_time[64];
strftime(date_time, sizeof(date_time), "%Y-%m-%d %H:%M:%S", localtime_r(&us.tv_sec, &t));
printf("gettimeofday: date_time=%s, tv_usec=%ld\n", date_time, us.tv_usec);
}
int main(int argc, char* argv[])
{
nowtime_ns();
printf("\n");
nowtime_us();
printf("\n");
return 0;
}
#include <time.h>
// 返回自系統開機以來的毫秒數(tick)
unsigned long GetTickCount()
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return (ts.tv_sec * 1000 + ts.tv_nsec / 1000000);
}
int main()
{
struct timespec time1 = { 0, 0 };
clock_gettime(CLOCK_REALTIME, &time1);
printf("CLOCK_REALTIME: %d, %d\n", time1.tv_sec, time1.tv_nsec);
clock_gettime(CLOCK_MONOTONIC, &time1);
printf("CLOCK_MONOTONIC: %d, %d\n", time1.tv_sec, time1.tv_nsec);
clock_gettime(CLOCK_MONOTONIC_RAW, &time1);
printf("CLOCK_MONOTONIC_RAW: %d, %d\n", time1.tv_sec, time1.tv_nsec);
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time1);
printf("CLOCK_PROCESS_CPUTIME_ID: %d, %d\n", time1.tv_sec,
time1.tv_nsec);
clock_gettime(CLOCK_THREAD_CPUTIME_ID, &time1);
printf("CLOCK_THREAD_CPUTIME_ID: %d, %d\n", time1.tv_sec,
time1.tv_nsec);
printf("\n%d\n", time(NULL));
printf("tick count in ms: %ul\n", GetTickCount());
return 0;
}