timers with pthread

Can somebody provide me example of starting and stop an userdefined timer on PTHREAD concepts ?

Basically, like this. one thread started TIMER1, now other thread on TIMER1 with value x need to stop the TIMER1 and start TIMER2.

Please help me.

for ex:

In the following program, can somebody suggest me to start another THREAD and cancel the the timer which i started currently when it is delayed for 3secs.

Code:

struct timeval tv; 

int set_timer(struct timeval &tv,time_t sec)
{
 gettimeofdat(&tv,NULL);
 tv.tv_sec += sec;
 return 1;
}

void* timer(void* arg)
{
   set_timer(tv,5);
}
  
int main(int argc, char* argv[])  
 {  
 
pthread_create (&thread_id, NULL,&timer,NULL);
pthread_join(&thread_id);

}