Function CMTextFormatDescriptionGetFontName 

pub unsafe extern "C-unwind" fn CMTextFormatDescriptionGetFontName(
    desc: &CMFormatDescription,
    local_font_id: u16,
    font_name_out: NonNull<*const CFString>,
) -> i32

Available on crate feature CMFormatDescription only.

Returns the font name for a local font ID.

Some format descriptions carry a mapping from local font IDs to font names. The function returns kCMFormatDescriptionError_ValueNotAvailable for format descriptions that do not carry such a font mapping table.

Safety

font_name_out must be a valid pointer.