Function CGGetDisplaysWithOpenGLDisplayMask 

pub unsafe extern "C-unwind" fn CGGetDisplaysWithOpenGLDisplayMask(
    mask: CGOpenGLDisplayMask,
    max_displays: u32,
    displays: *mut CGDirectDisplayID,
    matching_display_count: *mut u32,
) -> CGError

Available on crate features CGDirectDisplay and CGError only.

Safety

• displays must be a valid pointer or null.
• matching_display_count must be a valid pointer or null.