GetTimeOfDay Question

[Suneel Kandru <suneel.kandru@xxxxxxxxxxxxxxxxxxx>]

I want to find the data transfer time

 

I have code like this 

 

  timeRetVal = gettimeofday(&tp,&tz);
  if(timeRetVal != -1)
        lStartTime = tp.tv_usec;

Transferdata();

  timeRetVal = gettimeofday(&tp,&tz);
  if(timeRetVal != -1)
  {
       lEndTime = tp.tv_usec;
       }

lTime = lEndTime - lStartTime;

 

How come some times lEndTime value is less than lStartTime value is there any other function to get the tick count.

Thanks