How can i get UTCTime in millisecond since January 1, 1970 in c language
For Unix and Linux you could use gettimeofday.
For Win32 you could use GetSystemTimeAsFileTime and then convert it to time_t + milliseconds:
void FileTimeToUnixTime(FILETIME ft, time_t* t, int* ms)
{
LONGLONG ll = ft.dwLowDateTime | (static_cast<LONGLONG>(ft.dwHighDateTime) << 32);
ll -= 116444736000000000;
*ms = (ll % 10000000) / 10000;
ll /= 10000000;
*t = static_cast<time_t>(ll);
}
If you want millisecond resolution, you can use gettimeofday() in Posix. For a Windows implementation see gettimeofday function for windows.
#include <sys/time.h>
...
struct timeval tp;
gettimeofday(&tp);
long int ms = tp.tv_sec * 1000 + tp.tv_usec / 1000;
It's not standard C, but gettimeofday()
is present in both SysV and BSD derived systems, and is in POSIX. It returns the time since the epoch in a struct timeval
:
struct timeval {
time_t tv_sec; /* seconds */
suseconds_t tv_usec; /* microseconds */
};
This works on Ubuntu Linux:
#include <sys/time.h>
...
struct timeval tv;
gettimeofday(&tv, NULL);
unsigned long long millisecondsSinceEpoch =
(unsigned long long)(tv.tv_sec) * 1000 +
(unsigned long long)(tv.tv_usec) / 1000;
printf("%llu\n", millisecondsSinceEpoch);
At the time of this writing, the printf() above is giving me 1338850197035. You can do a sanity check at the TimestampConvert.com website where you can enter the value to get back the equivalent human-readable time (albeit without millisecond precision).