Function libxslt::bindings::xmlXPathRegisterFuncLookup

pub unsafe extern "C" fn xmlXPathRegisterFuncLookup(
    ctxt: *mut _xmlXPathContext, 
    f: Option<unsafe extern "C" fn(*mut c_void, *const u8, *const u8) -> Option<unsafe extern "C" fn(*mut _xmlXPathParserContext, i32)>>, 
    funcCtxt: *mut c_void
)