Re: Make copyObject work in C++

Peter Eisentraut <peter@eisentraut.org>

From: Peter Eisentraut <peter@eisentraut.org>

To: Jelte Fennema-Nio <postgres@jeltef.nl>

Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Thomas Munro <thomas.munro@gmail.com>, Andres Freund <andres@anarazel.de>

Date: 2026-03-23T09:27:51Z

Lists: pgsql-hackers

Attachments

nocfbot-0001-Try-test_cplusplusext-with-MSVC.patch (text/plain) patch 0001

On 13.02.26 11:28, Jelte Fennema-Nio wrote:
> After discussing the topic in-person with Peter at FOSDEM. We agreed
> that the best road forward was to not bother with MSVC for now. No-one
> has actually expressed an interest in being able to build C++ extension
> using MSVC, and the effort to support it is both non-trivial and not
> without downsides to the rest of the codebase. We can always come back
> to this later, possibly requiring C++20 on MSVC.

I checked what would currently be missing to get MSVC supported. 
Attached is the patch.

I think we should commit the pg_list.h changes, since the C-style 
compound literals are not a C++ feature at all, and so without this MSVC 
would never get supported.  (Or you couldn't use PostgreSQL lists, which 
would be very limiting.)

Here is a Compiler Explorer link that I used to check that the generated 
code doesn't change: https://godbolt.org/z/ovKKzEfs6

The other changes deal with designated initializers and flexible array 
members.  These are not a blocker, since extension authors could deal 
with them themselves by adding appropriate compiler options or similar.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Enable test_cplusplusext with MSVC
- c05ad248f99c 19 (unreleased) landed
Disable some C++ warnings in MSVC
- 82a7cbea747c 19 (unreleased) landed
meson: Make room for C++-only warning flags for MSVC
- 4c83f1253593 19 (unreleased) landed
Make fixed-length list building macros work in C++
- f8e7ca328510 19 (unreleased) landed
Make unconstify and unvolatize use StaticAssertVariableIsOfTypeMacro
- 258248d0bdbf 19 (unreleased) landed
Use typeof everywhere instead of compiler specific spellings
- e2308350c9b7 19 (unreleased) landed
Test List macros in C++ extensions
- 3d28ecb5ac76 19 (unreleased) landed
Test most StaticAssert macros in C++ extensions
- 451650eaacd5 19 (unreleased) landed
Revert "Change copyObject() to use typeof_unqual"
- 0af05b5dbb42 19 (unreleased) landed
Fix for C++ compatibility
- b4555cb070f1 19 (unreleased) landed
tests: Add a test C++ extension module
- 476b35d4e311 19 (unreleased) landed