Function CTFontManagerIsSupportedFont 

pub unsafe extern "C-unwind" fn CTFontManagerIsSupportedFont(
    font_url: &CFURL,
) -> bool

Available on crate feature CTFontManager only.

Determines whether a file is in a supported font format.

This function does not validate any font data, so clients using it must still be prepared to handle failed registration or font descriptor creation.

Parameter fontURL: A file URL.

Returns: This function returns true if the file is in a supported font format.