al_resume_timer - Allegro 5 API

       Resume  the  timer  specified.   From then, the timer’s counter will increment at a constant rate, and it
       will begin generating events.  Resuming a timer that is already started does nothing.  Resuming a stopped
       timer will not reset the timer’s counter (unlike al_start_timer(3alleg5)).

       al_resume_timer - Allegro 5 API

al_start_timer(3alleg5), al_stop_timer(3alleg5), al_get_timer_started(3alleg5)

Allegro reference manual                                                                al_resume_timer(3alleg5)

              #include <allegro5/allegro.h>

              void al_resume_timer(ALLEGRO_TIMER *timer)