Function gdk_pixbuf_sys::gdk_pixbuf_save_utf8

pub unsafe extern "C" fn gdk_pixbuf_save_utf8(
    pixbuf: *mut GdkPixbuf, 
    filename: *const c_char, 
    type_: *const c_char, 
    error: *mut *mut GError,
     ...
) -> gboolean

This is supported on Windows only.