C++获取系统毫秒级时间(自1970年1月1日至今的毫秒数)
//跟系统时间相关的
#ifdef _WIN32
#include <time.h>
#include <windows.h>
#else
#include <sys/time.h>
#endif
unsigned long long GetCurrentTimeMsec()
{
#ifdef _WIN32
struct timeval tv;
time_t clock;
struct tm tm;
SYSTEMTIME wtm;
GetLocalTime(&wtm);
tm.tm_year = wtm.wYear - 1900;
tm.tm_mon = wtm.wMonth - 1;
tm.tm_mday = wtm.wDay;
tm.tm_hour = wtm.wHour;
tm.tm_min = wtm.wMinute;
tm.tm_sec = wtm.wSecond;
tm.tm_isdst = -1;
clock = mktime(&tm);
tv.tv_sec = clock;
tv.tv_usec = wtm.wMilliseconds * 1000;
return ((unsigned long long)tv.tv_sec * 1000 + (unsigned long long)tv.tv_usec / 1000);
#else
struct timeval tv;
gettimeofday(&tv, NULL);
return ((unsigned long long)tv.tv_sec * 1000 + (unsigned long long)tv.tv_usec / 1000);
#endif
}