display_get_windows_alternate_sync();
Returns: Boolean
This Windows only function can be used to get the current vertical synchronisation method at runtime. It will return true if you have active the alternative method v-sync method, or false if you are using the regular v-sync option. Note that this does not report if v-sync is active or not (you can switch function display_reset()), and that you can set the v-sync method from the global game settings or using the function display_set_windows_alternate_sync().
if !display_get_windows_alternate_sync()
{
display_set_windows_alternate_sync(true);
}
The above code will check to see if the v-sync method is using the alternative or the default, and if it's the default it will switch to the alternative instead.