Re: EV_SET() better C++ compat with alternative implementations

[christos%astron.com@localhost (Christos Zoulas)]

In article <3ebcc5d1-a57d-a290-72d8-6efc73025985%gmx.com@localhost>,
Kamil Rytarowski  <n54%gmx.com@localhost> wrote:
>-=-=-=-=-=-
>-=-=-=-=-=-
>
>On 11.08.2019 02:56, Valery Ushakov wrote:
>> Kamil Rytarowski <n54%gmx.com@localhost> wrote:
>> 
>>> Cast of udata from void* to intptr_t shall be done with
>>> reinterpret_cast<> otherwise a C++ compiler errors.
>>>
>>> Defining __REINTERPRET_CAST [1] and using it, did not work as a compiler
>>> protested for NULL argument "warning: passing NULL to non-pointer argument".
>>>
>>> Using double cast __REINTERPRET_CAST(intptr_t, __CAST(void *, (udata)))
>>> pacified the warning/error about passing NULL in C++, but it created the
>>> problem of calling EV_SET using the native argument type intptr_t.
>> 
>> You are reporting quite an abstract summary that is not so easy to
>> follow for someone who hasn't done all the same experiments that you
>> already have done.
>
>
>$ cat /tmp/test.cpp
>
>
>#include <sys/types.h>
>#include <sys/event.h>
>
>int
>main(int argc, char **argv)
>{
>        struct kevent kv;
>
>        EV_SET(&kv, 0, 0, 0, 0, 0, 0);
>        EV_SET(&kv, 0, 0, 0, 0, 0, NULL);
>        EV_SET(&kv, 0, 0, 0, 0, 0, nullptr);
>        EV_SET(&kv, 0, 0, 0, 0, 0, 0L);
>        EV_SET(&kv, 0, 0, 0, 0, 0, 0LL);
>        EV_SET(&kv, 0, 0, 0, 0, 0, 0U);
>        EV_SET(&kv, 0, 0, 0, 0, 0, 0UL);
>        EV_SET(&kv, 0, 0, 0, 0, 0, 0ULL);
>        EV_SET(&kv, 0, 0, 0, 0, 0, (intptr_t)0);
>        EV_SET(&kv, 0, 0, 0, 0, 0, (uintptr_t)0);
>
>
>        return 0;
>}

How about:

        EV_SET(&kv, 0, 0, 0, 0, 0, 'a');
        EV_SET(&kv, 0, 0, 0, 0, 0, 0.0);

and all the other integral types not mentiones above?

So if we are going to go gung ho C++, why not do it as a template?
You could also possibly use std::is_integral (or the c++17 std::is_integral_v)
etc., and perhaps get rid of the diagnostic suppression :-)

christos