Provided by: allegro5-doc_5.2.10.1+dfsg-1build1_all 

NAME
al_add_timer_count - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro.h>
void al_add_timer_count(ALLEGRO_TIMER *timer, int64_t diff)
DESCRIPTION
Add diff to the timer’s counter value. This is similar to writing:
al_set_timer_count(timer, al_get_timer_count(timer) + diff);
except that the addition is performed atomically, so no ticks will be lost.
SEE ALSO
al_set_timer_count(3alleg5)
Allegro reference manual al_add_timer_count(3alleg5)