Question

Using only ANSI C, is there any way to measure time with milliseconds precision or more? I was browsing time.h but I only found second precision functions.

Answer 1

There is no ANSI C function that provides better than 1 second time resolution but the POSIX function gettimeofday provides microsecond resolution. The clock function only measures the amount of time that a process has spent executing and is not accurate on many systems.

You can use this function like this:

struct timeval tval_before, tval_after, tval_result;  gettimeofday(&tval_before, NULL);  // Some code you want to time, for example: sleep(1);  gettimeofday(&tval_after, NULL);  timersub(&tval_after, &tval_before, &tval_result);  printf('Time elapsed: %ld.%06ld\n', (long int)tval_result.tv_sec, (long int)tval_result.tv_usec); 

This returns Time elapsed: 1.000870 on my machine.