C :: Trigger Different Timers At The Same Time

The issue is that I am trying to run a code which can trigger different timers at the same time. That is, when 3 is typed by the user, the firstimer is triggered. If before expiration another 3 is introduced, the second timer will be launched, and the difference between both triggers will be shown. Under this circumstance, timer_gettime only works once. I tried all the things I could imagine but still, it_value_tv_sec and _nsec return zero after the first expiration.

-Theoretically, and following the manuals, once the timer is restarted the gettime function should work as it does the first time.
-I have also tried to removed the timer and start it again, but in this case the timers are still being triggered, but the gettime outputs(even the first time) are nonsense.

Here is the code I am testing: [CODE]#include<stdio.h>

Code:
#include<signal.h>
#include<time.h>
timer_t firstTimerID;
timer_t secondTimerID;
timer_t thirdTimerID;

[Code] ......