Thread: Get time in nanoseconds

  1. #1
    Registered User
    Join Date
    Jun 2017
    Posts
    3

    Get time in nanoseconds

    Hello


    The following code calculates the values in nanoseconds:

    Code:
             for(int i=1; i<=39; i++){
                 long startTime = java.lang.System.nanoTime();         
                 System.out.println("Hello world");
                 long endTime = java.lang.System.nanoTime();
                 System.out.println((endTime - startTime)); 
             }
    I would like to do the same in C:
    There are some code examples in the internet such as:

    Code:
    #include <sys/time.h>
    #include <stdio.h>
    #include <unistd.h>
    int main()
    {
        struct timeval start, end;
        long mtime, seconds, useconds;
    
        for(int sx=1; sx<=39; sx++){
    
            gettimeofday(&start, NULL);
            printf("Hello world");
            gettimeofday(&end, NULL);
    
            printf("Elapsed time: %ld microsecons\n", end.tv_usec - start.tv_usec);
    
         }
    
        return 0;
    }
    Unfortunately this returns a 0 microseconds value. And a multiplication of 1000 doesn't change at all.

    Can anyone help please?

    Thx,
    Troix

  2. #2
    and the hat of int overfl Salem's Avatar
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    Calculate time in microseconds or nanoseconds
    No need to keep spamming the board just because your first post got put into a moderation queue.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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