Function libpng_sys::ffi::png_get_tRNS

pub unsafe extern "C" fn png_get_tRNS(
    png_ptr: &png_struct, 
    info_ptr: &mut png_info, 
    trans_alpha: *mut *mut u8, 
    num_trans: &mut c_int, 
    trans_color: *mut *mut png_color_16
) -> u32