How to get the current time in milliseconds from C in Linux?

Question

How do I get the current time on Linux in milliseconds?

Answer 1

This version need not math library and checked the return value of clock_gettime().

#include 
#include 
#include 

/**
 * @return milliseconds
 */
uint64_t get_now_time() {
  struct timespec spec;
  if (clock_gettime(1, &spec) == -1) { /* 1 is CLOCK_MONOTONIC */
    abort();
  }

  return spec.tv_sec * 1000 + spec.tv_nsec / 1e6;
}