How do I get the current time on Linux in milliseconds?
This can be achieved using the POSIX clock_gettime
function.
In the current version of POSIX, gettimeofday
is marked obsolete. This means it may be removed from a future version of the specification. Application writers are encouraged to use the clock_gettime
function instead of gettimeofday
.
Here is an example of how to use clock_gettime
:
#define _POSIX_C_SOURCE 200809L
#include <inttypes.h>
#include <math.h>
#include <stdio.h>
#include <time.h>
void print_current_time_with_ms (void)
{
long ms; // Milliseconds
time_t s; // Seconds
struct timespec spec;
clock_gettime(CLOCK_REALTIME, &spec);
s = spec.tv_sec;
ms = round(spec.tv_nsec / 1.0e6); // Convert nanoseconds to milliseconds
if (ms > 999) {
s++;
ms = 0;
}
printf("Current time: %"PRIdMAX".%03ld seconds since the Epoch\n",
(intmax_t)s, ms);
}
If your goal is to measure elapsed time, and your system supports the "monotonic clock" option, then you should consider using CLOCK_MONOTONIC
instead of CLOCK_REALTIME
.