Lin George wrote: > I am not sure whether it is the correct place to ask a bug of gettimeofday here. It's not. The function is implemented by whatever C library your platform provides. gcc does not include a C library. Note that mentioning what platform you're using when posting to a mailing list is always a good idea, otherwise you can only expect nonspecific answers. gcc is used on dozens and dozens of platforms, so you cannot assume we have any idea what you're doing. > I found sometimes the time will not be increased, but will be decreased. It does not happen each time, but happens rarely. > > Here is my program and output, are there anything wrong. > > Output > -------------------- > begin second and micro-second is: 1155819609 -- 653911 > print begin time > 2006-08-17 13:00:09.653 > end second and micro-second is: 1155819609 -- 635116 > print end time > 2006-08-17 13:00:09.635 I suppose a daemon like ntp (or perhaps the kernel itself) might be adjusting for clock skew here by periodically subtracting small amounts of time. Brian
