retrace_count(3) - Linux man page
Name
retrace_count - Retrace count simulator. Allegro game programming library.
Synopsis
#include <allegro.h>
extern volatile int retrace_count;
Description
If the retrace simulator is installed, this count is incremented on each vertical retrace; otherwise, if
the refresh rate is known, the count is incremented at the same rate (ignoring retraces); otherwise, it is incremented 70 times a second. This provides a way
of controlling the speed of your program without installing user timer functions.
See Also
ex3d(3), exblend(3), exdbuf(3), exflip(3),
exlights(3)