clock, clock_t and GTK

["mauzil libero it" <mauzil libero it>]

Hi all.

I make an application that communicate via serial line at 19200,n,8,1
and has 3 idle functions.
One idle function get data for serial line and update a widget.
One update a widget. The latter control a process quering the system by
"clock" POSIX function e updating a label with the time value.

Why the time value in the label changes slower that real-time?

That is. I start countdown. After real 5 minutes the label display 3
minutes.

Why this difference? Is GTK lib that change time or is kernel linux that
makes wrong operations?

The kernel is 2.4.5.

Thanks to all.
	Mauro Ziliani