Simple Function Timing for C/C++

gistfile1.cpp

//The includes required
#include "time.h"
#include "stdio.h"

FILE *logfile;

/*
 *  Compares two time intervals and returns the time
 *  difference in milliseconds.
 */
int getTimeDiff(timeval t1, timeval t2) {
    long elapsed_seconds = t2.tv_sec  - t1.tv_sec;
    long elapsed_useconds = t2.tv_usec - t1.tv_usec;

    //Return time difference in milliseconds
    return ((elapsed_seconds) * 1000 + elapsed_useconds / 1000.0) + 0.5;
}

/*
 *  Returns the current time in a timeval struct
 */
timeval getTime(void) {
    timeval currentTime;
    gettimeofday (&currentTime, NULL);
    return currentTime;
}

//...
//Initialization, most likely called in constructor or via onCreate
//we append to the log file, so be sure to delete it between runs
logfile = fopen("/sdcard/yourlog.log", "a");
//...

//...
//Cleanup, most likely in your destructor or via onPause.
//Don't forget to call this, if you do your log file won't
//be written.
fclose(logfile);
//...

void aFunctionToTime(){
    //The variables to store time and intervals
    timeval t1, t2, t3, t4, t5;
    int i1, i2, i3, i4;
    
    //Now spread your time variables like seeds in the wind...
    t1 = getTime();
    
    someLongRunningFunction();
    
    t2 = getTime();
    //... More stuff to time
    t3 = getTime(); //etc...
    
    //All done, time to calculate intervals and scribble to the log
    i1 = getTimeDiff(t1, t2);
    i2 = getTimeDiff(t2, t3);
    i3 = getTimeDiff(t3, t4);
    i4 = getTimeDiff(t4, t5);
    fprintf(logfile, "%d %d %d %d\n", i1, i2, i3, i4);
    
    //Import to excel as space delimited
}