public inbox for [email protected]  

help / color / mirror / Atom feed

From: Jelte Fennema-Nio <[email protected]>
To: Thomas Munro <[email protected]>
Cc: Bertrand Drouvot <[email protected]>
Cc: [email protected]
Subject: Re: Safer hash table initialization macro
Date: Fri, 5 Dec 2025 15:32:32 +0100
Message-ID: <CAGECzQSnhom3wFnY6a7xepGfxzzVmwyNCcJQE=y8UYS-g2G=RQ@mail.gmail.com> (raw)
In-Reply-To: <CA+hUKG+TuQPXtfkaam6trfLrk+OXf89zUt7Jx27zEY-y8i1swA@mail.gmail.com>
References: <aS2b3LoUypW1/[email protected]>
	<CAGECzQSHb6FxuSdYNY7tt8SKFw2dianACvkExrWRmTBfy-CkjQ@mail.gmail.com>
	<aTAcV/[email protected]>
	<[email protected]>
	<CA+hUKG+TuQPXtfkaam6trfLrk+OXf89zUt7Jx27zEY-y8i1swA@mail.gmail.com>

On Fri, 5 Dec 2025 at 02:30, Thomas Munro <[email protected]> wrote:
> How much of our header stuff is supposed to work from C++ too?

I think it's nice if it works, but it doesn't seem the most important.
Especially since C++ has its own hashmaps. And if it really needs to
create a hashmap it's still possible to call the.

> I suppose you could
> write the typeof-based version you already hinted at, but only use it
> for __cplusplus__ (where typeof exists as decltype).

I tried to figure something out that would work in C++ (with help of
Claude), but I wasn't able to create a version of the macros without
also needing to add:

#ifdef __cplusplus
}
#include <type_traits>
extern "C" {
#endif

It seems quite ugly to escape the extern "C" from the parent like that
and then re-enter it. Overall it doesn't seem worth the hassle to me
to make these macros work in C++.

> Another consideration is what impact we have on the Rust world, and
> potentially other languages used for extensions that call C via FFI
> etc

FFI generally cannot call macros anyway, only actual symbols.

view thread (17+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Safer hash table initialization macro
  In-Reply-To: <CAGECzQSnhom3wFnY6a7xepGfxzzVmwyNCcJQE=y8UYS-g2G=RQ@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox