wtime.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*   File:         wtime.c                                                   */
/*   Description:  a timer that reports the current wall time                */
/*                                                                           */
/*   Author:  Wei-keng Liao                                                  */
/*            ECE Department Northwestern University                         */
/*            email: wkliao@ece.northwestern.edu                             */
/*   Copyright, 2005, Wei-keng Liao                                          */
/*                                                                           */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>

double wtime(void) 
{
    double          now_time;
    struct timeval  etstart;
    struct timezone tzp;

    if (gettimeofday(&etstart, &tzp) == -1)
        perror("Error: calling gettimeofday() not successful.\n");

    now_time = ((double)etstart.tv_sec) +              /* in seconds */
               ((double)etstart.tv_usec) / 1000000.0;  /* in microseconds */
    return now_time;
}

#ifdef _TESTING_
int main(int argc, char **argv) {
    double time;

    time = wtime();
    printf("time of day = %10.4f\n", time);

    return 0;
}
#endif