install_int (3) - Linux Man Pages
install_int: Installs a user timer handler. Allegro game programming library.
install_int - Installs a user timer handler. Allegro game programming library.
int install_int(void (*proc)(), int speed);
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.
Returns zero on success, or a negative number if there is no room to add
a new user timer.