Function GetMonitorRedGreenOrBlueGain 

pub unsafe fn GetMonitorRedGreenOrBlueGain(
    hmonitor: HANDLE,
    gtgaintype: MC_GAIN_TYPE,
    pdwminimumgain: *mut u32,
    pdwcurrentgain: *mut u32,
    pdwmaximumgain: *mut u32,
) -> i32