SYNOPSIS
#include <allegro.h>
int install_int(void (*proc)(), int speed);
DESCRIPTION
Installs a user timer handler, with the speed given as the number of milliseconds between ticks. This is the same thing as install_int_ex(proc, MSEC_TO_TIMER(speed)). If you call this routine without having first installed the timer module, install_timer() will be called automatically. Calling again this routine with the same timer handler as parameter allows you to adjust its speed.RETURN VALUE
Returns zero on success, or a negative number if there is no room to add a new user timer.