al_set_new_display_refresh_rate
void al_set_new_display_refresh_rate(int refresh_rate)
Sets the refresh rate to use when creating new displays on the calling thread. If the refresh rate is not available, al_create_display will fail. A list of modes with refresh rates can be found with al_get_num_display_modes and al_get_display_mode.
The default setting is zero (don't care).
See also: al_get_new_display_refresh_rate
Examples: ex_vsync
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